Annual Meeting of the
SOUTHERN ONTA R IO N EU ROSC IEN C E ASSOCIA TION (SONA)
Michael G. DeGroote Centre for Learning and Discovery McMaster University – May 8, 2009 SONA is southern Ontario’s chapter of the Society for Neuroscience. Its aims are: first, to advance the understanding of the nervous system, including the part played in determining behaviour, by bringing together neuroscience researchers of various backgrounds; secondly, to promote neuroscience education; and thirdly, to inform the general public about current research. The SONA Annual Meeting provides a full day of research talks and posters in an informal, friendly atmosphere. The annual membership fee is $25 for faculty and $15 for trainees. Membership includes registration fee for SONA meeting, lunch, and refreshments. LOCAL ORGANIZING COMMITTEE: Jane A. Foster
Associate Professor, McMaster University
Psychiatry Resident, M.Sc. Candidate, MiNDS Graduate Program, McMaster University
Ph.D. Candidate, MiNDS Graduate Program, McMaster University
Michelle M. Sidor
Ph.D. Candidate, Medical Sciences Graduate Program, McMaster University
FOR MORE INFORMATION PLEASE CONTACT US: Email – email@example.com Website – firstname.lastname@example.org
Sign in and poster set-up
Francesco Leri, University of Guelph A "novel" method for assessing the reinforcing efficacy of drugs of abuse
Sid Segalowitz, Brock University Risk-taking and the anterior cingulate cortex: How the brain regulates our unwise behaviour (or doesn't !)
coffee/tea/sna cks Student Talks Michelle Sidor, PhD candidate, Medical Sciences Graduate Program, McMaster University The molecular signature of anxiety-like behaviour in mice exposed to a postnatal immune challenge
Vladimir Miskovic, PhD Candidate, MiNDS Graduate Program, McMaster University The neurobiological consequences of early life adversity in humans: central and autonomic concomitants
Ryan Van Lieshout, Psychiatry Resident, PhD Candidate, MiNDS Graduate Program, McMaster University Babies big and small: Exploring the impact of suboptimal intrauterine environments on mental health across the lifespan
walk to The Bistro on campus
LUNCH – meet the professor – an opportunity for trainee/faculty networking
POSTER SESSION – MDCL first floor
KEYNOTE ADDRESS – John Yeomans, University of Toronto From Brain Rewards to Human Disease Genes: Sex, Drugs and Singing Mice
SONA Business Meeting
Talks are in MDCL 1105.
Posters in south east corner.
Allen, CP Abadilla, R Ahmed, S Al-khatib, A Amting, JM Atkinson, L Aubie, B Bain, JR Baltazar, RM Bannon, DR Barnes, E Barsyte, D Basu, D Bateman, K Bawa, D Becker, S Belliveau, DJ Beltran, M Berger, RG Bernier, SM Bienenstock, J Bobeica, I Brown, E Brown, IR Brown, T Brudzynski, SM Buttigieg, J Cain, DP Chan, T Chen, L Chen, RHC Cheng, G Chiappetta, K Choleris, E Chow, AM Christenson, K Chrostowski, M Chung, C Clark, J Clark, MM Coolen, LM Crutchley, MC Cummins, E Cumyn, EM Cusi, A D'Cruz, J D'Cunha, TM
1 71 25 90 2 63 3 42 98 35 15 43 85 23 56 3, 10, 89 65 15 27 65 67 96 5 8, 37 6 41 79 12 59 99 97 81 7 35, 71 8, 37 9 10 11 62 71 4, 5, 16, 23, 44, 60, 72, 81, 87, 99 12 9 13 14 18 19
Davis, O Dawood, S de Oliverira, CVR deCatanzaro, D Derjean, D Di Sebastiano, AR Diez d'Aux, N Donoghue, DJPorter, LA Dubuc, R Erb, S Eubanks, J Euler, K Fahnestock, M Faure, PA Feng, Z Ferguson, CS Fernandes, A Fidalgo da Silva, E Fleming, AS Fong, J Foster, JA Francis, BM Frohmader, KS Frost, DO Galea, V Goldreich, D Good, D Good, D Goodman, RL Graham, D Green, WW Greene, B Greening, SG Grella, S Griffin, JK Gupta, V Guzzo, AC Hackett, A Hall, G Hastings, R Higgs, DM Hinds, A Ho, K Hui, Kwokyin Ioannou, M Jacklin, D Jackson, L Jamal, L Johnson, SA
15 54 4, 87 27 25 16 17 15 25 34, 43 18, 56, 73, 82, 84, 94 29 11, 28, 32, 42, 51, 77 3 31 20 31 15 19, 63 66 21, 40, 67, 76, 80, 83 22 23, 72 51 24 70, 93 7 68 44, 60 59, 90 25 90 2 26 45, 46 65 27 28 61, 64 29 53, 96 30 45, 46 31 11, 32 90 60 33 34
Jones, C Jung, H Katare, Y Kennedy, J Kereliuk, MR Khalouei, S Khokhar, JY King, M Kolozsi, E Komadoski, MD Korol, A Kraemer, GW Kupferschmidt, Da Ladha, Z Laframboise, A Lam, E Lee, A Lee, E Lee, TM Lehman, MN Leri, F Leung, LS Levine, B Levy, F Limbeer, CL Loeb, SJ Lomanowska, AM Lopez, JP Lougheed, RE Lovejoy, SA Low, J Lubanska, D Lumani, A Ma, J Ma, K Mac, J MacDougall, A MacKenzie, R MacKenzie, RN MacQueen, G Maimaiti, J Maliszewska-Cyna, E Mancini, C Market, B Mann, A Masoudi, R Matthews, S May, HY McKinnon, MC
65 35 36 63 36 37 38 39 21, 40 41 42 49, 50 43 44 36 46 48 47 5 5, 44, 60, 81, 98 1, 9, 26, 48, 91 12 39 19 91 36 49, 50 51 52 43 53 99 54 12 55 46 39 40 21, 80 14, 21, 39, 40, 61, 64, 83 15 56 30 99 57 77 63 58 14, 39, 61
McLaurin, J McMurran, T Meaney, M Mercier, AJ Merkley, C Meusel, L Michalski, B Miksys, S Milakovic, M Mileva-Seitz, V Mills, LR Milne, AMB Mishra. RK Mitchell, DGV Mobin, S Mong, JA Mooney, SJ Morley, M Mount, HTJ Mutabdzic, D Nahirny, AP Nailey, A Nelson, AJ Nestler, EJ Neufeld, KM Niles, LP Noseworthy, MD Nurse, CA Ormerod, K Orth, C Padmanabhan, V Parker, LA Peters, RM Phan, A Piacenza, FM Pitchers, KK Popescu, A Porter, LA Raheleh, M Reyes, R Rilett, KC Roberts, JC Roberts, VM Robinson, BH Rothwell, CM Rotzinger, S Rzeczkowska, PA Safir, A Salman, S
46, 55 59 63 58, 62, 69, 86, 88 60 61 51 20, 38 62 63 66, 82 64 85 2 15 71 50 65 13, 22, 45, 46, 55, 97 84 66 4 17, 95 72 67 74 92 79 69 35 5, 81 91 70 71 34 72 73 99 32 75 76 77 71 13 78 43 74 94 79
Sankar, A Schmid, S Scott, AP Sediqzadah, S Senzel, A Sharma, R Shen, B Sheppard, KM Shulyakova, N Sidhu, M Sidor, M Sidorova, E Sokolowski, MB Sookram, C Spencer, GE Spong, K St채mpfli, MR Stanciu, M Staudt, MD Steidl, S Steier, M Szechtman, H Tandon, A Tenk, C Thomas, N Tierney, K Torontali, Z Toulouse, T Truitt, WA Tsai, ML Tucci, MC Tuerke, KJ Turnbull, J Tyndale, RF Van Amerigan, M van Noordt, S Vialou, V Visanji, N Wasserman, D Webb, IC Wong, M Wong, OL Wong, R Woody, E Yang, J Yeomans, J Yonekura, N Yong-Yow, S Yucel, K
80 6 36 34 31 90 12 81 82 65 83 84 63 85 78 86 76 97 87 47 63 30, 97 4 85 36 88 89 4 12 90 91 52 20, 30 68 72 97 47 98 93 92 92 30 13, 29, 94 16 21
59, 89, 90
Zavalishina, L Zhang, G Zhang, H Zhang, L Zielinski, BS Ziluk, A
94 73 33, 54 94 25, 36 95
POSTER INDEX 1. Craig P. Allen and Francesco Leri. Perseveration in sucrose seeking following cocaine sensitization in rats. 2. Jayna M. Amting, Steven G. Greening, and Derek G.V. Mitchell. Dominant versus suppressed representations of fear and disgust: The neural correlates of emotional awareness. 3. Brandon Aubie, Sue Becker, and Paul A. Faure. Millisecond Level Temporal Selectivity in Neural Circuits. 4. Allisha Bailey, Cleusa V.R. de Oliveira, William A. Truitt, Christine Tenk, and Lique M. Coolen. The role of galanin in a spinothalamic pathway regulating sexual reward and satiety in the male rat. 5. Erinna Brown, Theresa M. Lee, Vasantha Padmanabhan, Michael N. Lehman, and Lique M. Coolen. Sex differences and the effect of prenatal testosterone on dopamine cells of the ventral tegmental area in sheep. 6. Tyler Brown and Susanne Schmid. Prepulse inhibition of startle: involvement of brainstem nicotine receptors. 7. Katie Chiappetta and Dawn Good. Social decision making in university students with mild head injury. 8. Ari M. Chow and Ian R. Brown. Interaction of heat shock protein 70 (HSP70) family members. 9. Kayla Christenson, Erin Cummins, and Francesco Leri. Effect of acute methadone on a reference memory task. 10. Michael Chrostowski and Suzanna Becker. Modeling adaptation in the auditory cortex to causally link neural synchrony to tinnitus. 11. Crystal Chung, Maria Ioannou, and Margaret Fahnestock. Activation of AKT survival signal by ProNGF in PC12 cells. 12. Crutchley, M.C., Tsai, M.L., Ma, J., Shen, B., Cain, D.P., and Leung, L.S. Long-term deficits in auditory gating after a model of immature rat seizures induced by GABAB receptor blockade. 13. Elizabeth M. Cumyn, Jimao Yang, Brian H. Robinson, and Howard T. J. Altered affect and disrupted bioenergetic homeostasis in mice expressing human A30P !-synuclein. 14. A Cusi, G MacQueen, and MC McKinnon. Theory of mind and empathy deficits in bipolar disorder. 15. Davis O., Fidalgo da Silva E., Maimaiti J., Barnes E., Beltran M., Mobin S., Donoghue D.J. and Porter L.A. The role of Tuberin and Cyclin B1 interaction in the developing embryonic brain. 16. Andrea R. Di Sebastiano, Sabrina Yong-Yow, and Lique M. Coolen. The role of orexin in sexual behavior and sexual reward of the male rat.
17. Natalie Diez d’Aux and Aimee J. Nelson. Area 5 to primary motor cortex projection during rest and tonic contraction: a TMS study. 18. Jennifer D'Cruz and James Eubanks. Alterations of cortical and hippocampal network activity In MeCP2-deficient mice. 19. Tracey M. D’Cunha, Frederic Lévy, and Alison S. Fleming. The effects of microinfusions of oxytocin into the nucleus accumbens shell on maternal memory in female spraguedawley rats. 20. Charmaine S. Ferguson, Sharon Miksys, and Rachel F. Tyndale. The effect of nicotine and ethanol on CYP2B6 in African Green monkeys. 21. Jane A. Foster, Kaan Yucel, Edith Kolozsi, Robyn N. MacKenzie, and Glenda MacQueen. Risk alleles of the serotonin transporter polymorphism predict small hippocampal volumes in major depression. 22. Beverly M. Francis, Jimao Yang, and Howard T.J. Mount. Dexefaroxan reverses cognitive and affective phenotypes in TgCRND8 mice. 23. Karla S. Frohmader, Katherine Bateman, and Lique M. Coolen. Taking the risk: effects of Methamphetamine on sexual behavior in male rats. 24. Victoria Galea. Altered Perception affects action in hypnoticomotor tasks. 25. Warren W. Green, Sana Ahmed, Dominique Derjean, Réjean Dubuc, Barbara S. Zielinski. Spatial analysis of olfactory bulb activity in the sea lamprey. 26. Stephanie Grella and Francesco Leri. The effect of acute stress on reacquisition of heroin self-administration in rats. 27. Adam C. Guzzo, Robert G. Berger, and Denys deCatanzaro. Tritium-labelled estradiol in male urine binds in the uterus and brain of inseminated female mice (Mus Musculus): Implications for the Bruce effect. 28. Aaron Hackett and Margaret Fahnestock. Brain derived neurotrophic factor-opposite strand expression and its potential regulatory role in cognitive impairment: work in progress. 29. Robert Hastings, Ken Euler, and John Yeomans. Ethanol preference in B6 strain mice Is reduced by M5 muscarinic receptor knockout or naltrexone, but reversed by food deprivation or long-term ethanol exposure. 30. Andrea Hinds, Henry Szechtman, Michael Van Ameringen, Catherine Mancini, and Erik Woody. Obsessive-compulsive disorder as a dysfunction of security motivation. 31. Kwokyin Hui, Abigail Fernandes, Anthony Senzel, and Zhong-Ping Feng. Method of analysis of real-time PCR that is independent of efficiency determination. 32. Maria S. Ioannou, Raheleh Masoudi, and Margaret Fahnestock. The biological activity of ProNGF is determined by the relative levels of TrkA and P75NTR receptors.
33. Lina Jamal and Huiming Zhang. Auditory corticofugal projections to the auditory thalamus and the auditory midbrain in the rat. 34. Sarah A. Johnson, Saadia Sediqzadah, Franca M. Placenza, and Suzanne Erb. Conditioned locomotion and structural plasticity in the amygdala after repeated cocaine administration: assessment after brief and extended drug-free periods. 35. Jung, H., Orth, C., Bannon, D. R., and Choleris, E. The effects of an indirect cannabinoid agonist on social approach and object placement in male CD-1 mice. 36. Kereliuk, M.R., Katare, Y., Tierney, K., Laframboise, A., Scott, A.P., Loeb, S.J., and Zielinski. Attraction of female round gobies to steroids released by males. 37. Sam Khalouei, Ari M. Chow, and Ian R. Brown. Expression of HSP70 family members in cultured neuronal cells. 38. Jibran Y. Khokhar, Sharon Miksys, and Rachel F. Tyndale. CYP2B Is induced in the rat brain by chronic nicotine treatment: Induction time course. 39. Matthew King, Arlene MacDougall, Brain Levine, Glenda MacQueen, and Margaret C. McKinnon. Autobiographical memory in recurrent major depressive disorder and bipolar disorder: Moderating effects of emotion and mood state. 40. Edith Kolozsi, Robyn MacKenzie, Glenda MacQueen, and Jane A. Foster. Cytokine polymorphisms in people with major depression. 41. Melanie D. Komadoski, Stefan M. Brudzynski, Effect of quinpirole on production of 50 kHz ultrasonic calls in wistar rats. 42. Anna Korol, James R. Bain, and Margaret Fahnestock. Regulation of GDNF mRNA in rat myotubues. 43. Kupferschmidt DA, Barsyte D, Rotzinger S, Lovejoy DA, and Erb S. Effects of teneurin cterminal associated peptide-1 (TCAP-1) on stress-induced reinstatement of cocaine seeking. 44. Zamin Ladha, Lique M. Coolen, Robert L. Goodman, and Michael N. Lehman. The effects of thyroid hormone on neurotrophin expression during seasonal transitions in the ewe. 45. Keith Ho, Jennifer K. Griffin, and Howard T.J. Mount. Is there a cytoprotective role for DJ-1 in a mouse model of ataxia-telangiectasia? 46. Emily Lam, Keith Ho, Jennifer Griffin, Jennifer Mac, Mary Brown, JoAnne McLaurin, and Howard T.J. Mount. Behavioural phenotypes of DJ-1-deficient mice implicate altered transmission in multiple brain areas and are differentially affected by Atm expression. 47. Esther Lee, Stephan Steidl, David Wasserman, and John S. Yeomans. Opiate-induced locomotion deficits in M5 muscarinic receptor knockout mice are reversed after food deprivation.
48. AnneMarie Levy and Francesco Leri. Oreo cookies = cocaine? 49. A.M. Lomanowska and G.W. Kraemer. Social deprivation of infant rats differentially alters responding to a conditioned cue depending on its predictive value. 50. S. J. Mooney, A. M. Lomanowska, and G. W. Kraemer. Social isolation of infant rats followed by resocialization in a complex environment results in perseverative reversal learning deficits. 51. Juan Pablo Lopez, Bernadeta Michalski, Douglas O. Frost, and Margaret Fahnestock. Decreased processing of ProBDNF to BDNF in visual cortex of dark-reared mice. 52. Rosamond E. Lougheed and John Turnbull. The effects of a novel drug combination and voluntary exercise in a survival study using an ALS mouse model. 53. Jennifer Low and Dennis M. Higgs. Acute effects of cadmium on octavolateralis structure and function in the fathead (Pimephales promelas) and bluntnose minnows (Pimephales notatus). 54. Ariana Lumani, Sara Dawood, and Huiming Zhang. Novelty detection neurons in the ratâ€™s dorsal cortex of the inferior colliculus. 55. Keran Ma, JoAnne McLaurin, and Howard T.J. Mount. Analysis of A" and neuroinflammation as a function of brain region and disease progression in the TgCRND8 brain. 56. Ewelina Maliszewska-Cyna, Damanpreet Bawa, and James Eubanks. Altered NMDAR expression and localization in an animal model of rett syndrome â€“ possible role in rett syndrome pathophysiology? 57. Mann, Amandeep and Tyndale, F. Rachel. A role of CYP2D6 in protection against MPP+ neurotoxicity in SH-SY5Y human neuroblastoma cells. 58. Holly Y. May and A. Joffre Mercier. Social experience influences responses to reflection in Drosophila melanogaster. 59. Thomas McMurran, Derek Ng, Tiffany Chan, Dawn Graham, and Henry Szechtman. Role of the lateral orbitofrontal cortex in the development and expression of quinpiroleinduced compulsive checking in rats. 60. Christina Merkley, Lique M. Coolen, Leslie Jackson, Robert Goodman, and Michael N. Lehman. Transcriptional activation of kisspeptin neurons and glutamatergic inputs to kisspeptin during the preovulatory GnRH surge of the sheep. 61. Liesel-Ann Meusel, Margaret McKinnon, Geoffrey Hall, and Glenda MacQueen. Evidence for sustained improvement in memory deficits following computer-assisted cognitive remediation in patients with a mood disorder. 62. Maja Milakovic, Julie Clark, and A. Joffre Mercier. Mechanisms underlying modulation of muscle contraction by a Drosophila neuropeptide.
63. Viara Mileva-Seitz, James Kennedy, Leslie Atkinson, Marla B Sokolowski, Meir Steiner, and Alison Fleming, PIs: Michael Meaney, Stephen Matthews. Genes, environment, and maternal behaviour. 64. Andrea M.B. Milne, Geoffrey B.C. Hall, and Glenda M. MacQueen. Abnormal hippocampal activation in patients with minimal or extensive past history of major depression: An fMRI study. 65. Melissa Morley, Claire Jones, Vishal Gupta, Mandeep Sidhu, Suzanne M. Bernier, Walter J. Rushlow, and Daniel J. Belliveau. PKC Inhibition Increases gap junction intercellular communication and cell adhesion in human neuroblastoma. 66. Adrian P. Nahirny, Jamie Fong, and Linda R. Mills. Elevated intracellular calcium upregulates mitochondrial protein import in differentiated PC12 cells and in rat cortical neurons. 67. Karen-Anne M. Neufeld, John Bienenstock, and Jane A. Foster. The impact of intestinal microbiota on anxiety-like behaviour. 68. van Noordt, S. and Good. D. Mild head injury in university students: physiological anticipation, decision-making, and contemplation in social dilemmas. 69. Kiel Ormerod and A. Joffre Mercier. Does thermal acclimatization alter effects of a cholesterol chelator on synaptic transmission and impulse propagation? 70. Ryan M. Peters and Daniel Goldreich. Finger size, not sex, determines tactile spatial acuity. 71. Phan, A., Roberts, V.M., Abadilla, R., Mong, J.A., Choleris, E., and Clark, M.M. Correlation of male Mongolian gerbil social behaviours with estrogen receptor alpha and oxytocin expression in the brain. 72. Kyle K. Pitchers, Karla S. Frohmader, Vincent Vialou, Eric J. Nestler, and Lique M. Coolen. DeltaFosB in the nucleus accumbens regulates sexual experience. 73. Andreea Popescu, G. Zhang, and J. Eubanks. Pharmacological rescue of nonsense mutations in rett syndrome. 74. Paulina A. Rzeczkowska and Lennard P. Niles. Mechanisms involved in melatonininduced histone H3 hyperacetylation in cultured neural cells. 75. Ricardo Reyes. Language processed as music and the role of the left inferior frontal cortex beyond phonological processing. 76. Kelly C. Rilett, Martin R. StĂ¤mpfli, and Jane A. Foster. Maternal smoke exposure results in hyperactivity. 77. Jillian C. Roberts, Raheleh Masoudi, and Margaret Fahnestock. Altered brain-derived neurotrophic factor mRNA in post mortem brain tissue of subjects with non-alzheimerâ€™s disease tauopathies suggests a novel role for pathologically modified tau.
78. Cailin M. Rothwell and Gaynor E. Spencer. The role of retinoic acid in long-term memory consolidation following operant conditioning. 79. Shaima Salman, Josef Buttigieg, and Colin A. Nurse. Molecular mechanisms involved in the postnatal loss of hypoxic sensitivity in adrenomedullary chromaffin cells: Role of Opioid receptor stimulation. 80. Ashwin Sankar, Robyn MacKenzie, and Jane A. Foster. Role of class I immune molecules in mediating sickness behaviour. 81. Kayla M. Sheppard, Lique M. Coolen, Guanliang Cheng, Vasantha Padmanabhan, and Michael N. Lehman. Prenatal programming by excess testosterone of appetite regulatory peptides in the arcuate nucleus of the female sheep. 82. Natalya Shulyakova, James H. Eubanks, and Linda R. Mills. SIRT3 overexpression protects differentiated PC12 cells from glucose deprivation or oxygen-glucose deprivation. 83. Michelle M. Sidor, Glenda MacQueen, and Jane A. Foster. The molecular signature of anxiety-like behaviour in mice exposed to a postnatal immune challenge. 84. Elena Sidorova, Dorotea Mutabdzic, and James Eubanks. Sirtuins 1 and 3 are expressed throughout development in central nervous system, and their levels decrease with age. 85. Christal Sookram, Nancy Thomas, Dipa Basu, and Ram K Mishra. Investigating the changes in Bcl2 and Bcl11b expression in the lymphocytes of individuals with schizophrenia. 86. Kristin Spong and A. Joffre Mercier. Detection of crayfish urine using fluorimetry. 87. Michael D. Staudt, Cleusa V.R. de Oliveira, and Lique M. Coolen. Activation of the MAP kinase signaling pathway and glutamate receptors in lumbar spinothalamic cells with ejaculation. 88. Zoltan Torontali and A. Joffre Mercier. Effects of testosterone on agonistic behaviour in crayfish. 89. Trent Toulouse and Henry Szechtman. TD learning versus motivational salience accounts of dopamine in animal models of OCD. 90. Tucci MC, Graham D, Jacklin D, Sharma R, Greene B, Al-khatib A, Kafil T, Beerepoot P, and Szechtman H. Comorbidity of depressive-like behaviour in the quinpirole model of obsessive-compulsive disorder. 91. Katharine J. Tuerke, Cheryl L. Limebeer, Francesco Leri, and Linda A. Parker. Nauseainducing and antidepressant effects of paroxetine on rats. 92. Oi Lei Wong, Raimond Wong, and Michael D. Noseworthy. Development of an fMRI temperature-sensitive protocol for chemotherapy-induced peripheral neuropathy.
93. Michael Wong and Daniel Goldreich. What drives tactile spatial acuity enhancement in the blind: tactile experience or visual deprivation? 94. Zavalishina L., Safir A., Yonekura N., Logan R., Zhang L., and Eubanks J. MBD2, another methyl-CPG-binding protein, contributes to autism-like behavioural phenotype in mice. 95. Angela Ziluk and Aimee J. Nelson. Neural projection from area 5 to primary motor cortex in healthy adults: a TMS study. 96. Irina Bobeica and Dennis M. Higgs. Effects of noise on the auditory sensitivity in a hearing generalist, the round goby, Neogobius melanstomus. 97. Robert H.C. Chen, Naomi Visanji, M. StanciuHoward T.J. Mount, and Anurag Tandon. Characterization of RAB3A and !-synuclein interaction and consequences on a !synuclein compartmentalization. 98. Ricardo M. Baltazar, Ian C. Webb, Lique M. Coolen, and Michael N. Lehman. Diurnal variation in reward, mesolimbic tyrosine hydroxylase and clock gene expression in the male rat. 99. Lubanska D, Market B , Chen L and Porter LA. Role of Spy1 in neural differentiation. Implications in the development of neurological cancers.
POSTER #1 Perseveration in Sucrose Seeking Following Cocaine Sensitization in Rats Craig P. Allen, PhD Student; Francesco Leri, PhD, - Dept of Psychology, University of Guelph Rationale: Perseverative responding refers to persistence of a response that was previously appropriate but then became associated with negative consequences. Perseveration is a detrimental component of a number of disorders, including drug addiction, obsessive compulsive disorder, Parkinsonâ€™s disease, and perhaps most notably, pathological gambling. The purpose of our study was to determine whether chronic cocaine exposure could cause an increase in perseverative responding in rats tested on a novel reversal procedure. Cocaine was selected on the basis of previous research which suggests that both the dopaminergic system and prefrontal cortex functioning are associated with perseveration and that both systems are altered by cocaine. Additionally, cocaine users are known to show greater levels of perseverative responding compared to normal controls. Experiment 1: Since food deprivation is known to cause cocaine sensitization this test was conducted to determine if chronic exposure could cause further sensitization in food-restricted animals. Half of the rats were food-restricted to 85% of their free-fed weight for 10 days prior to the start of testing. Following this, all rats received a baseline test of locomotion to an acute cocaine challenge of 3, 5, 9, or 15 mg/kg. Rats then received daily injections of 30 mg/kg cocaine for 5 consecutive days. After 10 days in their home cages the rats were given a second locomotion test. Results indicated that food-restricted animals showed elevated levels of locomotion at baseline when injected with either 9 or 15 mg/kg cocaine. Furthermore, both food-restricted and free-fed animals showed sensitization following chronic cocaine exposure. Experiment 2: To test perseveration we used a model that makes use of the ratsâ€™ natural propensity to favour options which offer the lowest effort-to-reward ratio. Following initial learning of lever pressing, the rats were given training sessions in which they chose between levers on either a variable ratio 15 (VR15) or a fixed ratio 25 (FR25) schedule of reinforcement. Rats quickly learned to preferentially respond on the more favourable VR15 lever. After 3 training sessions they were given a test of perseveration. To test perseveration the VR15 schedule was converted to a progressive ratio (PR) schedule. During the early stages of the test the PR lever is more favourable to the FR25 lever, but as response requirements increase on the PR lever the FR25 lever becomes the more favourable ratio causing the animal to switch. The amount of responding observed on the PR lever after it has become the less favorable choice is an index of perseveration. Rats were given 6 tests (1 cycle) on each of 3 different PR schedules which varied in rate of escalation (18 tests in total). After completing these tests, rats were given 5 daily injections of saline or 30 mg/kg cocaine followed by 10 days in their home cage. The rats were then underwent the same testing for perseveration a second time (6 tests/PR schedule, 3 schedules). Results indicated that cocaine treated animals showed significantly more perseveration than saline-treated animals at the beginning of the three PR/FR25 cycles. Cocaine treated animals also made significantly fewer conservative errors on the FR25 lever on all of the tests. Experiment 3: This experiment tested the effect of acute cocaine on perseveration. Procedure was similar to experiment 2 except that on the 6th test of each cycle rats were given an injection of saline they were then given a 7th test immediately following an injection of 0, 1, or 3 mg/kg cocaine. There was no significant effect of acute cocaine on perseveration. Conclusion: These results indicate that chronic but not acute cocaine is capable of altering perseverative responding for sucrose in rats. This deficit, however, is eliminated by further training, suggesting that the effect of cocaine sensitization on this aspect behavior can be modified by appropriate experiences.
POSTER #2 Dominant versus suppressed representations of fear and disgust: The neural correlates of emotional awareness Jayna M. Amting1, 2, Steven G. Greening1, 2, and Derek G.V. Mitchell1, 2 1
Department of Psychiatry, 2Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada Background: Previous studies have shown that a specialized emotion-related area of the brain, the amygdala, is activated by emotional visual stimuli even in the absence of awareness. Current models of consciousness propose that awareness of a visual stimulus requires either: a) feedforward processing of stimuli from early visual areas to the ventral visual system; or b) a combined feedforward sweep and feedback loop from early visual areas to temporal cortex and back. However, these models are based on studies involving neutral visual stimuli, which data suggest interact with attention in a different manner than do emotional stimuli. As a consequence, the pattern and loci of neural activation required for an emotional visual stimulus to reach awareness is not yet known. Previous work in our lab suggests that when multiple emotional stimuli are present, they are processed in a competitive fashion, with distinct brain regions giving greater or less weight to positive versus negative stimuli. These data implicate a neural circuit involving the amygdala and medial prefrontal cortex in selecting the appropriate emotion to respond to during conflict. We hypothesized that, in a similar fashion, emotional stimuli are selected for awareness through coordinated activity in the occipital cortex, amygdala, and medial prefrontal cortical cortex, which acts as an emotional feedback loop for awareness. Objectives: In the present study, currently underway, we manipulated the presentation of conflicting emotional faces using a binocular rivalry paradigm in order to determine the neural basis of emotional awareness. Specifically, we examined the neural activity associated with the awareness and suppression of conflicting facial expressions. We hypothesized that coordinated activity in medial prefrontal cortex, the amygdala, and occipital cortex would be associated with emotional awareness. Methods: Binocular rivalry, a visual awareness paradigm in which dissimilar objects are presented to each eye, allows for the examination of how objects compete for perceptual dominance. Although both images are represented by early visual areas in both hemispheres, one object is consciously experience while the other is suppressed from awareness. Our binocular rivalry paradigm consisted of two superimposed facial expressions (one red, the other blue in colour), which were viewed through a blue filter over one eye and a red filter over the other. The faces depicted disgusted, fearful, and neutral expressions. The binocular rivalry paradigm was completed by healthy volunteers (N=20) in a 3Tesla fMRI scanner. Volunteers were required to report the dominant facial expression on each trial via button presses. Results: Data indicated that perceptual suppression of a fearful stimulus (i.e., a fearful face was present but not consciously perceived) was associated with significant increase in blood oxygenation level dependent (BOLD) activity in the medial prefrontal cortex. Conclusion: Early results support the idea that emotional awareness involves coordinated activity in the pathways associated with medial prefrontal cortex and amygdala, and visual cortex and amygdala. Follow-up functional connectivity analyses are currently underway to help elucidate and differentiate the neural pathways that support awareness of disgusted and fearful facial expressions
POSTER #3 Millisecond Level Temporal Selectivity in Neural Circuits Brandon Aubie, PhD Student; Sue Becker, PhD; Paul A. Faure, PhD Department of Psychology, Neuroscience & Behaviour, McMaster University Discrimination of stimulus duration on the order of milliseconds has been observed in behavioural and neurophysiological studies across a variety of species and taxa. Studies conducted in mammals have found neurons in the auditory midbrain (inferior colliculus) selective for signal duration that are referred to as duration tuned neurons (DTNs). This study formulates three computational models that amalgamate existing conceptual models with observed physiological responses in the central auditory midbrain of the bat. The computational models reproduce a wide range of responses seen in vivo including duration tuning response classes, spike counts, first-spike latencies, level tolerance to changes in signal amplitude, best duration tuning, and neuropharmacological effects of inhibitory neurotransmitter antagonists applied to DTNs in vivo. The first model, a coincidence model, was first proposed by Narins and Capranica (1980). An onset-evoked excitatory post-synaptic potential (EPSP) arrives at the DTN after some delay from stimulus onset that, on its own, does not drive the DTN to produce action potentials. An offset-evoked EPSP also arrives at the DTN after a short delay from the stimulus offset. Because the onset-evoked EPSP is delayed, a stimulus with an appropriate duration can cause the onset-evoked EPSP to coincide with the offset-evoked EPSP. When this occurs, the DTN is driven supra-threshold and action potentials are produced. The second model, an anti-coincidence model, was first proposed by Fuzessery and Hall (1999). As in the first model, an onset-evoked EPSP arrives at the DTN after some delay from stimulus offset, however, this EPSP is strong enough to evoke action potentials in the DTN on its own. An inhibitory post-synaptic potential (IPSP) lasting the duration of the stimulus provides inhibition to the DTN. If the stimulus duration is short enough such that the delayed onsetevoked EPSP arrives after the IPSP, then the DTN will produce action potentials. As the stimulus duration increases, the duration of inhibition will increase and thus overlap with the onset-evoked EPSP, cancelling out any excitation. The third model, another anti-coincidence model, was first proposed by Faure et al. (2003) to explain another class of DTNs that are selective to stimulus durations of at least a specific duration. An EPSP lasting the duration of the stimulus provides excitation to the DTN. Additionally, an IPSP is present for the first several milliseconds of the stimulus and thus the EPSP is cancelled out. At longer stimulus durations, the IPSP diminishes in strength after the first several milliseconds and permits the EPSP to break through and produce action potentials. Each computational model is supported by in vivo data thus we hypothesize no single mechanism is responsible for all duration tuned response classes observed in the auditory midbrain. Furthermore, we suggest that each model can be generalized under a unified model of duration tuning where the three models proposed here are specific instantiations of that general model. Faure et al. (2003) Journal of Neuroscience, 23(7):3052-3065. Fuzessery and Hall (1999) Hearing Research, 137(1-2):137-154. Narins and Capranica (1980). Brain, Behaviour and Evolution, 17(1):48-66.
POSTER #4 The Role of Galanin in a Spinothalamic Pathway Regulating Sexual Reward and Satiety in the Male Rat Allisha Bailey1, Cleusa V.R. de Oliveira2, William A. Truitt3, Christine Tenk2, and Lique M. Coolen1,2 Depts. of Anatomy and Cell Biology1 and Physiology and Pharmacology2, University of Western Ontario, London, Ontario, 3Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA. Ejaculation is the most rewarding aspect of sexual behavior. However the neural pathways that process ejaculation-related signals from the reproductive organs to the brain are unknown. Moreover, how these signals contribute to the perception of sexual reward and sexual satiety is unclear. Recently our laboratory identified a candidate spinothalamic pathway in the position to process ejaculation-related cues. This pathway consists of a population of lumbar spinothalamic cells projecting to the medial parvocellular subparafascicular thalamic nucleus (mSPFp), and expresses the neuropeptide galanin. Here, we hypothesize that this pathway and galanin in particular, is essential for the processing of ejaculation-related information and contributes to sexual reward and satiety. Previously, our laboratory found that galanin, when injected into the mSPFp inhibits all components of copulatory behavior. Here, we tested the effects of galanin and galanin receptor antagonist infusions in mSPFp on development of mating-induced conditioned place preference (CPP) and satiety. Sexually experienced male rats received bilateral cannulas directed towards the mSPFp. mSPFp injections of 500 ng galanin was paired with a CPP chamber, with saline as control. Animals developed CPP for the galanin paired chamber. Next, we tested the effects of mSPFp infusions of the galanin receptor antagonist galantide, on sexual satiety and reward. Sexually experienced male rats received bilateral cannulas directed towards the mSPFp. Animals received mSPFp infusions of 0.1 nmol or 0.5 nmol galantide and mated with a receptive female until satiety. Galantide did not affect sexual performance or satiety. Next, animals underwent a CPP paradigm where animals received 0.5 nmol galantide or saline, were allowed to mate and placed in the paired chamber. Galantide prevented the development of mating-induced CPP. In contrast, mating-induced CPP was significant in saline-treated males. Together these results suggest that galanin is released in the mSPFp following ejaculation where it acts as a mediator for the processing of ejaculationrelated information and contributes to the regulation of sexual reward and satiety. Support: NSERC to LMC
POSTER #5 Sex differences and the effect of prenatal testosterone on dopamine cells of the ventral tegmental area in sheep Erinna Brown, M.Sc. Student, Graduate Studies in Anatomy and Cell Biology, University of Western Ontario; Theresa M. Lee, PhD, Department of Psychology, University of Michigan; Vasantha Padmanabhan, PhD, Department of Pediatrics, University of Michigan; Michael N. Lehman, PhD, Department of Anatomy and Cell Biology, University of Western Ontario; Lique M. Coolen, PhD, Department of Anatomy and Cell Biology, University of Western Ontario Prenatal testosterone (T) exposure in sheep results in a wide array of reproductive neuroendocrine deficits that closely resemble the reproductive and metabolic features of polycystic ovarian syndrome (PCOS). Many women suffering from PCOS have eating disorders and negatively affected sexual functioning. Likewise, prenatal T-treated sheep show alterations in goal-directed behaviours and increased reward for food, as well as masculinized and defeminized sexual behaviour. The neural sites targeted by prenatal T that mediate these alterations in eating and mating are unknown. Here, we hypothesized that the ventral tegmental area (VTA) dopamine neurons, which play a critical role in reward and motivation, are influenced by prenatal T. Indeed, studies in rodents have shown that VTA dopamine neurons express steroid receptors and are sexually dimorphic. In the current study, we investigated if VTA dopamine cells in sheep are sexually dimorphic and affected by prenatal T treatment. Sections of the rostral midbrain containing the VTA of female sheep treated prenatally with T during gestation days 60-90 (n=6), control female (n=9), and control male (n=8) sheep were simultaneously processed for tyrosine hydroxylase (TH) as a marker for dopamine neurons. Males had significantly more TH-positive neurons in the VTA compared to control females and prenatal T-treated females; however, prenatal T-treated females had significantly more THpositive cells compared to control females (p<0.001). Differences in intensity of TH staining were observed, with more extensive dendritic and soma labeling in males and prenatal Ttreated females than control females. Together, these data demonstrate sexual dimorphism in the VTA dopamine system in sheep and the ability of prenatal T to masculinize the female mesolimbic dopamine system. Supported by NIH P01 HD44232 awarded to TL, VP, and MNL; NIH HD41098 awarded to VP.
POSTER #6 Prepulse inhibition of startle: involvement of brainstem nicotine receptors Tyler Brown, Susanne Schmid Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario, Canada N6A 5C1 Prepulse inhibition (PPI) is an attenuation of a startle response brought-on by a non-startling sensory stimulus (prepulse) presented 10-1000ms before the startle-evoking stimulus. It is a measure of sensory gating that is important to conserve mental processing resources. In schizophrenia, and other mental disorders, PPI and the ability to properly filter-out sensory stimuli are severely impaired, causing cognitive deficits. Interestingly, nicotine consumption partially restores PPI and improves cognitive performance. In fact, approximately 90% of people suffering from schizophrenia smoke cigarettes, presumably as a form of self-medication. Furthermore, the !7-nicotinic receptor has been identified as a susceptibility gene for schizophrenia. Therefore, our goal was to elucidate the role that nicotinic receptors play in PPI. We examined the neural area where the PPI pathway converges with the startle pathway: the caudal pontine reticular nucleus (PnC). Specifically, we hypothesized that activation of nicotinic receptors in the PnC is necessary for normal PPI. Bilateral cannulae targeting the PnC were chronically implanted in Sprague Dawley rats, and microinjections of nicotinic antagonists were administered prior to PPI testing. The !7-specific nicotinic antagonist MLA (0.1 mM; 0.5ÂľL), significantly inhibited PPI by 13.0% (Âą4.3%) compared to saline injections (p=0.014) , but only at a short interstimulus interval of 12 ms. TMPH (0.1mM; 0.5 ÂľL), a nicotinic antagonist that does not block !7, had no significant effect on PPI. Higher doses of both drugs are currently tested. Our data suggest that !7-nicotinic receptor activation in the PnC partly mediates PPI at short interstimulus intervals. Agonists that activate !7-nicotinic receptors might therefore be beneficial for clinical populations suffering from disruption of PPI and associated cognitive deficits.
POSTER #7 Social Decision Making in University Students with Mild Head Injury Katie Chiappetta1 & Dawn Good, Ph.D., C. Psych.2 1
Undergraduate Honours Neuroscience Student, Brock University Department of Psychology and Centre for Neuroscience, Brock University
The goal of this research was to examine if history of mild head injury (MHI) influences aspects of social decision-making. Forty-four University students (11 males, 33 females), 18 reporting an MHI, completed self-report measures of impulsivity and social problem solving, as well as evaluating different levels of social dilemmas (non-moral, moral impersonal and moral personal). Participants reporting MHI perceive themselves as equally competent problem solvers compared to the non-MHI group. As expected, people with an MHI evaluate factors related to decision-making differently in terms of solution implementation and verification especially with regards to moral personal dilemmas, such that appropriateness ratings for moral transgressions were inversely related to oneâ€™s solution verification (p < .05) for students in the non-MHI group; whereas there was no relationship for students in the MHI group. As well, the likelihood of committing a moral transgression was different between the two groups, such that the non-MHI group was more likely to commit a moral impersonal transgression (e.g. steal money) relative to a moral personal transgression (e.g. kill someone); whereas, the opposite was found with the MHI group. Further, persons with MHI make decisions significantly more quickly than do those in the non-MHI group (p < .03), and while their response time to judge nonmoral decisions is significantly faster than for more difficult decisions, they judge impersonal and personal decisions equally fast (i.e. there is no additional challenge in committing to a personal moral transgression) unlike those with no reported MHI (who take significantly longer to rate personal transgressions) (p < .05). Overall, experiencing a previous MHI does not influence oneâ€™s perception of decision-making skills and strategies, yet the factors influencing those decisions for a person with or without MHI differs, as does the time devoted to social decision making.
POSTER #8 Interaction of heat shock protein 70 (HSP70) family members Ari M Chow, PhD; Ian R Brown, PhD, Center for the Neurobiology of Stress, University of Toronto at Scarborough The occurrence of aggregation-prone misfolded proteins is a common and signifying feature of a wide range of neurodegenerative disorders, including Alzheimerâ€™s disease, Parkinsonâ€™s disease, and amyotrophic lateral sclerosis (ALS). Heat shock proteins (Hsps) are protein repair agents that provide a line of defense against misfolded, aggregation-prone proteins. Targeting of misfolded protein intermediates and aggregates by Hsps could be employed as an effective therapeutic strategy against neurodegenerative diseases. The HSP70 family is well characterized for its cytoprotective effects against cell death and has previously been implicated as having neuroprotective capability in overexpression studies. HSP70 family members exhibit high sequence and structural conservation. The significance of the multiplicity of HSP70 proteins is unknown. Formation of heterocomplexes of HSP70 family members is a potential mechanism for regulation of HSP70 function and specificity. We have employed co-immunoprecipitation (co-IP) to determine if HSP70 family members interact with each other. After stringent tests of antibody specificity, we detect heterocomplex formation between HSP70 family members in differentiated human neurons grown in tissue culture. We also show that all of the HSP70 family members that were investigated are able to form stable complexes with Hsp40, suggesting the sharing of a common co-chaperone. Immunocytochemistry revealed that the HSP70 family members localize to neuronal cellular processes and growth cones.
POSTER #9 Effect of acute methadone on a reference memory task Kayla Christenson, B.A. student, University of Guelph Erin Cummins, Ph.D. student, University of Guelph Francesco Leri, Ph.D., University of Guelph The purpose of this study was to examine the effect of acute administration of methadone on performance of a well learned reference memory task in a parallel arm maze. The task involved training rats to approach the one of ten arms using environmental cues. After acquisition of the task, 32 male Sprague-Dawley rats received 0, 1.25, 2.5 and 5 mg/kg (SC) methadone according to a Latin square design, 15-30 min prior to testing. It was found that the highest dose of methadone significantly increased time to complete the task and decreased total number of arm entries. However, proportion of correct-to-incorrect arm choices did not differ significantly across drug doses. Therefore, animals injected with 5 mg/kg methadone, although behaviourally impaired, were still able to maintain normal levels of accuracy. From this, it is concluded that acute methadone may not impair cognitive functions per se, but slows down ability to perform.
POSTER #10 Modeling adaptation in the auditory cortex to causally link neural synchrony to tinnitus Michael Chrostowski, PhD student, McMaster Integrative Neuroscience Discovery & Study; Suzanna Becker, PhD, McMaster University; Ian Bruce, PhD, McMaster University Tinnitus, the phantom perception of sound in the absence of an external stimulus, is widely thought to persist because of lasting changes in neural activity arising in the auditory cortex after hearing loss. Masking sounds presented for a set duration and then turned off, can reduce the severity of the tinnitus percept temporarily, a phenomenon known as residual inhibition (RI) . The underlying mechanism for RI is not known; understanding it could provide insight into how changes in neural activity in the auditory cortex lead to persistent tinnitus. We propose that RI may be caused by long-term adaptation in the primary auditory cortex. We have developed a network-level spiking model of the primary auditory cortex that includes tonotopically arranged excitatory and inhibitory neural units. The hearing loss region is represented as one where input firing rates are decreased. Our model includes a homeostatic plasticity mechanism that strengthens the weights on excitatory connections to the deafferented neurons. The novel contribution here is the addition of an adaptation mechanism to account for RI. The transient decrease in tinnitus perception that occurs after masker stimulus presentation is accounted for by spiking adaptation that works on timescales as long as tens of seconds and has a similar effect on firing rates as has been found experimentally . We simulate experimental findings regarding appropriate stimulus bandwidth and duration for RI in order to validate our model. Additionally, spontaneous firing rates and synchrony in neural firing before and after stimulus presentation are analyzed to shed light on their potential causal link to tinnitus. Our simulations indicate that long-term adaptation in excitatory neurons of the primary auditory cortex can lead to a suppression in spontaneous firing rates that has a similar recovery timescale (15-45 seconds) as that of masker-induced tinnitus suppression. Furthermore, crosscorrelation values between neural units in the hearing loss region are noticeably lower (average of 26.2%) 10 seconds after a 30-second masker stimulus is simulated. Before the stimulus, our model shows enhanced neural synchrony in the hearing loss region, which has been found empirically . Thus, the masker presentation reduces firing synchrony to levels that are seen in the normal hearing regions of our model. Studies where an auditory masker was shown to temporarily suppress the perception of tinnitus indicate that neural activity underlying the tinnitus percept is being transiently affected by the masker stimulus. We show that spike frequency adaptation is a plausible candidate mechanism underlying this temporary suppression. Furthermore, our simulations show that, with the presence of adaptation, the enhanced neural synchrony seen with induced hearing loss is temporarily reduced by an appropriate auditory masker. This supports the argument that there is a causal link between enhanced neural synchrony and the perception of tinnitus. References  Roberts, L.E., Moffat, G., Bosnyak, D.J. (2006). Acta Oto-Laryngologica, 126:27-33.  Gourevitch, B. & Eggermont, J.J. (2008). European Journal of Neuroscience, 27:3310-3321.  Seki, S. & Eggermont, J.J. (2003). Hearing Research, 180:28-38.
POSTER #11 ACTIVATION OF AKT SURVIVAL SIGNAL BY PRONGF IN PC12 CELLS Crystal Chung, Undergraduate Student, Bachelor of Health Sciences Maria Ioannou, M.Sc. Student, Graduate Studies in Neurosciences Margaret Fahnestock, PhD, McMaster University Nerve growth factor (NGF) is a neurotrophin that supports neuronal survival, differentiation, and outgrowth. NGF is undetectable in the human central nervous system. Instead, its precursor, proNGF, is abundant within this tissue and binds to the same receptors, TrkA and p75, leading to the idea that observed biological activity is actually caused by proNGF rather than NGF. To determine the biological effects of this precursor, the downstream signalling proteins of TrkA were analyzed after treatment of PC12 cells with proNGF. In particular, the activity of Akt and Erk1/2, important cell survival signals downstream of TrkA, were analyzed. We found that proNGF does cause activation of Akt and MAPK in a dose dependent manner, similar to activation by NGF. Since Akt can be activated downstream of the p75 receptor as well, and since PC12 cells express both receptors, future experiments will examine activation of the Akt survival signal by proNGF in conditions where there are only TrkA receptors or where there are only p75 receptors. Our results indicate that proNGF exhibits biological activity that is very similar to the effects of NGF, suggesting proNGF could be naturally responsible for important biological activity within the human central nervous system.
POSTER #12 Long-term deficits in auditory gating after a model of immature rat seizures induced by GABAB receptor blockade Crutchley, M.C., MSc Candidate1; Tsai, M.L., MD, MSc1,2; Ma, J., MD, PhD2, Shen, B., MD2, Cain, D.P., PhD1,3, & Leung, L.S., PhD1,2 1
Graduate Program in Neuroscience, University of Western Ontario Department of Physiology and Pharmacology, University of Western Ontario 3 Department of Psychology, University of Western Ontario 2
The aim of this study was to investigate the long-term alterations in behavior after a new model of early-life hippocampal seizures. Seizure rats were injected with a GABAB receptor antagonist CGP56999A 1 - 1.5 mg/kg intraperitoneally (i.p.) on postnatal day 15, while controls were injected with saline or cerebrospinal fluid i.p. CGP56999A induced repeated seizures over ~ 8 h, originating mostly from the hippocampus and amygdala (Tsai, Shen & Leung, Epilepsy Res 79: 187). When 45-80 days old, seizure and control rats were tested with tasks of spatial navigation, prepulse inhibition, and auditory gating. The seizure rats were not different from control rats in prepulse inhibition of the acoustic startle, or in the acquisition and retention of the radial 8-arm maze (partially baited) and the Morris water maze. They were deficient, as compared to controls, in the gating of auditory evoked potentials in the hippocampus. Gating was demonstrated by a decrease in a 2nd click response as compared to the 1st click response (500 ms interclick interval). Components of the auditory evoked potentials at 15 â€“ 100 ms latency showed reversed polarity across the CA1 cell layer, suggesting that hippocampal neurons generated these components. In normal rats, gating of hippocampal auditory evoked potentials was disrupted by hippocampal infusion of a GABAB receptor antagonist. The lack of gating of hippocampal auditory evoked potentials is consistent with a decrease in GABAB-receptor inhibition in the hippocampus reported after CGP56999A-induced immature seizures. Seizure rats did not show clear cell loss (Nissl stain) or mossy fiber sprouting (Timmâ€™s stain) in the hippocampus as compared to controls (ibid.). The study underscores the long-term effects on hippocampal inhibition and behavioral functions after a cluster of brief hippocampal seizures in a developing animal. (Supported by CIHR MOP64433 and NSERC)
POSTER #13 Altered affect and disrupted bioenergetic homeostasis in mice expressing human A30P !-synuclein Elizabeth M. Cumyn, BSc1,2, Jimao Yang1, Brian H. Robinson, PhD4, Howard T. J. Mount, PhD1,2,3 Centre for Research in Neurodegenerative Diseases1, Institute of Medical Science2, Dept. Medicine (Div. Neurology)3 and Hospital for Sick Children4, University of Toronto Familial Parkinsonâ€™s disease is a synucleinopathy that can be caused by A53T or A30P point mutations in the !-synuclein gene, or by multiplication of the gene locus. Many PD patients suffer from depression and anxiety and experimental models suggest that their affective state may be related to !-synuclein load. We studied mice expressing human wild-type (WT) or mutant (A53T, A30P) !-synuclein transgenes to explore a possible relationship between pathogenic !-synuclein and affective behaviours. A30P-transgenic (Tg) mice exhibited increased behavioural despair in the tail suspension test and decreased anxiety in the elevated zero maze. These mice also exhibited increased serotonin turnover in cortex and striatum, which may contribute to behavioural despair and attenuation of anxiety. Bioenergetic dysfunction has been implicated in PD, and may underlie altered affect in !-synuclein transgenic mice. We measured high-energy phosphate donors in microwave-fixed brain tissue and found reduced cortical ATP in A30P-Tg mice. ATP was preserved WT-Tg and A53T-Tg cortex, and was elevated in WT-Tg hippocampus and cerebellum. Creatine, a buffer of intracellular ATP stores, tracked closely with ATP content, indicating that it either contributes to or reflects ATP levels. We next measured complex I+III activity in flash frozen tissue to determine whether altered ATP generation was contributing to changes in ATP content. A30PTg mice displayed decreased complex I+III activity in cortex, whereas activity was elevated in several WT-Tg brain areas, closely matching patterns of ATP alterations. Previous work showed constitutive activation of stress-activated protein kinase in mutant Tg brains. SAPK inhibits pyruvate dehydrogenase (PDH), an enzyme that generates ATP. We measured PDH activity and found that activity was decreased in A30P-Tg hippocampus and cerebellum, which is not strongly reflected in regional ATP levels. The A30P mutation caused regional depletion of ATP generation, resulting in decreased bioenergetic charge. This energy impairment corresponded to altered affect. Conversely, the increased ATP and mitochondrial enzyme activity in WT-Tg mice was reflected in some significant improvements in their behavioural performance relative to non-Tg littermate mice. Our results reveal linkages between expression of human A30P !synuclein, bioenergetic dyshomeostasis, and behavioural impairment that precede gross histological evidence of brain cell loss. Supported by Parkinson Society Canada and NSERC.
POSTER #14 Theory of Mind and Empathy Deficits in Bipolar Disorder A Cusi 1,2,3, BSc, PhD Student; G MacQueen4, MD/PhD; MC McKinnon1,2 PhD 1
Mood Disorders Program, St. Josephâ€™s Healthcare and the 2Department of Psychiatry and Behavioural Neurosciences and 3Graduate Program in Neuroscience, McMaster University and 4 Department of Psychiatry, University of Calgary Background: Despite early evidence of alterations in facial affect processing and in theory of mind in patients with mood disorders, little is known about the clinical and behavioural correlates of these impairments. Systematic investigations of other aspects of social cognition, including empathy are also rare. Goals: The purpose of our study is to examine the performance of individuals with BD on tasks pertaining to two interrelated aspects of social cognition, theory of mind (ToM) and empathy. A secondary goal of this study is to determine whether course of illness variables predicted social reasoning performance. Finally, we also sought to examine the relation between performance on these social cognitive tasks and real-world measures of social functioning. Methods: Bipolar disorder (BD) patients with recurrent illness and their matched controls completed a battery of well-validated social cognitive tasks shown previously to rely on cognitive and affective processing resources. These include theory of mind (ToM) tasks such as decoding mental states from pictures of eyes, detection of social faux pas, and a self-rated empathy questionnaire (Interpersonal Reactivity Index; IRI). Participants also received standardized measures of social functioning (Social Adjustment Scale-Self Report). Results: Relative to controls, BD patients were impaired on ToM tests including interpreting nonverbal cues such as facial expressions to make interpersonal judgments(p=0.01), detecting social faux pas(p=0.02), and a perspective-taking task(p=0.04). Moreover, these patients demonstrated greater deficits on second-order ToM tests involving a high cognitive load compared to first-order ToM measures with a low cognitive load(p=0.002). On the IRI, the BD group reported elevated levels of Personal Distress in response to othersâ€™ negative experiences(p=0.01). Deficits in ToM and empathic responding in these patients were associated with various domains of social adjustment, including Marital Relationship(p=0.02), Social Activities(p=0.02), and global social functioning(p=0.001). Conclusions: These results suggest that BD patients demonstrate impaired performance on a variety of social reasoning tasks. This effect was mediated by processing demands, with higher load tasks associated with greater impairment. Lowered social cognitive performance in the BD group was associated with impaired levels of everyday social functioning.
POSTER #15 The role of Tuberin and Cyclin B1 interaction in the developing embryonic brain Davis O1., Fidalgo da Silva E.1, Maimaiti J.1, Barnes E.2, Beltran M.2, Mobin S.2, Donoghue D.J.2 and Porter L.A.1 1
Biological Sciences Department, University of Windsor, 2Department of Chemistry and Biochemistry, UCSD
Tuberous sclerosis (TS) is an autosomal dominant disorder, either familial or sporadic in origin affecting 1:6000 live births individuals. TS is characterised by the development of benign tumor-like growths, known as hamartomas, which develop in a number of different organ systems, including the brain, heart (rhabdomyosarcomas), skin and kidneys. Due to the range of organ systems affected, TS presents with a diverse phenotypic spectrum, ranging from skin discolouration to seizures, mental retardation and death. Cortical tubers of the brain are the most prevalent lesions, occurring in >80% of TS patients and developing as early as 20 weeks gestation. Hence, this is a prevalent, profound childhood syndrome which currently lacks any benefits of therapeutic intervention. Genetically, TS is associated with mutations in either the TSC2 or TSC1 genes, which encode for the proteins Tuberin and Hamartin respectively. In vivo, these proteins function as a heterodimer known as the Tuberous Sclerosis Complex (TSC). The TSC plays an essential role in negatively regulating cellular proliferation and growth through an indirect influence on mTOR, which has previously been shown to be a key regulator of protein translation and synthesis and more recently has been implicated in regulating cell fate decisions during development. Data from a yeast-two-hybrid screen has determined that Tuberin is an interacting partner with the mitotic cyclin, Cyclin B1. We have since confirmed this data using both endogenous proteins and overexpression studies in a variety of different cell lines. Using a series of truncated mutants of Tuberin we have mapped the essential Cyclin B1 binding region within Tuberin. Functionally, Tuberin is capable of temporarily retaining Cyclin B1 within the cytoplasm, decreasing the number of mitotic cells. Additionally, a specific mutation within the Cyclin B1 binding region of Tuberin, where C696 is mutated to a Y (C696Y), decreases the affinity of tuberin for cyclin B1. This Tuberin mutant is unable to promote cytoplasmic retention of Cyclin B1 and thereby enhances mitotic progression. Importantly, this mutation is commonly observed within TS patients displaying the most severe neonatal CNS hamartomas and rhabdomyosarcomas. As such, we hypothesize that disruption of the interaction between Tuberin and Cyclin B1 will abrogate neural fate decisions, resulting in the dysregulation of neural development characteristic of TS. Tuberin and Cyclin B1 are proteins subject to a series of phosphorylation during the cell cycle. We show that the phosphorylation of cyclin B1 to start the mitosis decreases the interaction with tuberin. We are studying the effects of mutations and phosphorylation on the interaction of these proteins on neural fate decisions. Thus far, in human neuroblastoma SHSY5Y cells we have observed Tuberin levels to be relatively high in the nucleus prior to differentiation and overall levels to decrease significantly by day 6 following differentiation. The interaction of Tuberin and Cyclin B1 in the developing embryonic brain shows an exciting new avenue of Tuberin biology that has direct clinical relevance toward understanding the development and progression of TS. We demonstrate that Tuberin is not only an important regulator of the G1/S transition but it also plays an essential role in regulating cell movement into mitosis. Importantly we show that abrogation of this can result in growth signals which may underlie the key neurological defects posing the most severe consequences for patients with TS.
POSTER #16 The role of orexin in sexual behavior and sexual reward of the male rat Andrea R. Di Sebastiano, MSc Student, Department of Anatomy and Cell Biology, Sabrina Yong-Yow, BMSc Student, Department of Physiology and Pharmacology, Lique M. Coolen, PhD, Departments of Anatomy and Cell Biology and Physiology and Pharmacology, The University of Western Ontario The hypothalamic neuropeptide orexin has been demonstrated to play a role in reward related to drugs of abuse and is potentially involved in regulation of natural rewarding behaviors. Male sexual behavior has been shown to activate orexin neurons and this behavior is altered by administration of orexin receptor agonists or antagonists. However, the exact role of orexin in male sexual performance, sexual motivation and reward is currently unclear. Therefore, the goal of the current study was to test the hypothesis that orexin plays a critical role in sexual behavior, motivation and reward. First, using Fos as a marker for neural activation, we investigated activation of orexin neurons following different parameters of sexual behavior in male rats. It was demonstrated that orexin neurons become activated early in behavior with presentation of the female and remain activated for the duration of behavior. Next, we tested the functional role of orexin utilizing orexin-cell body specific lesions directed towards the hypothalamus. Adult male rats underwent orexin lesion or sham surgery using the targeted toxin orexin-saporin. Following two weeks recovery, sexual behavior was recorded over the course of four mating trials. During the first mating trial, males with complete lesions showed significantly shorter latencies to mount and intromit. This suggests that lesions facilitated sexual performance in naĂŻve animals. This facilitation was attenuated by sexual experience and was not evident during subsequent mating trials, indicating lesions do not have a facilitating effect on performance in experienced animals. Lesions also did not affect ejaculation latencies during any trial. Next, runway tests were conducted to determine maleâ€™s motivation to run towards a potential partner over two conditioning trials. Lesions appeared to facilitate sexual motivation, as lesion males demonstrated increased speed to run towards an estrous female during the second trial, whereas this effect did not reach significance in sham or partial lesion males. Finally, a conditioned place preference (CPP) paradigm was conducted as a measure of sexual reward. Lesion males failed to develop a significant preference for a sexual reward paired chamber indicating that orexin lesions block sexual reward. Overall, these findings suggest that orexin does not play a critical role in male sexual performance and motivation, however may play a critical role in sexual reward, and may be involved in general arousal related to sexual behavior. Supported by: NIH DA14591 to LMC
POSTER #17 Area 5 to primary motor cortex projection during rest and tonic contraction: a TMS study Natalie Diez dâ€™Aux, B.Sc. Student, Graduate Studies in Kinesiology; Aimee J. Nelson, PhD, University of Waterloo Brodmannâ€™s area 5 (BA 5) located in the superior parietal lobule is historically considered a higher-order somatosensory region. It is known to process somatic inputs related to touch and proprioception and is also tightly linked to the control of hand movements. For example, in humans, BA 5 is activated in fMRI studies during imagined finger movements. Of particular interest is the nature and the timing of the neural projection from BA 5 to primary motor cortex in humans. This projection can be probed using paired-pulse Transcranial magnetic stimulation (TMS) with two separate coils, one positioned over BA 5 and the other over primary motor cortex. The present experiment investigates this neural interaction using TMS during rest and also when the contralateral hand is contracted. It is hypothesized that during contraction of a muscle of the right hand the neural interaction between BA 5 and M1 would be altered relative to rest states. Eleven (right-handed) healthy volunteers (three male and eight female, 21-36 years old) participated in the experiment. Transcranial Magnetic Stimulation (TMS) was performed at the University of Waterloo using BiStim-2/Magstim 2002 stimulators with two customized 50 mm branding coils. Rest motor threshold and active motor threshold were collected prior to the experiment. The conditioning pulse (CS) was delivered using one coil positioned over BA 5 and followed by a test pulse (TS) delivered to the ipsilateral M1 using a second coil. The interval between the CS and TS was tested at the following interstimulus intervals; 6,8,10,12,30,40 and 50 ms. The dependent variable was the MEP amplitude in the FDI muscle during the conditioned state normalized to the unconditioned state (TS alone). Accurate placement of the M1 coil elicited a motor evoked potential (MEP) recorded in the right first dorsal interosseous (FDI) muscle. The participant was aligned with their MRI using Brainsight Neuronavigation system. The neural projection from BA 5 to M1 was recorded during two conditions 1) rest with both hands completely relaxed, and 2) during 10% MVC contraction of the right FDI. These conditions were tested with two CS intensities 1) 90% and 2) 110% of active or rest motor threshold, respectively. In each of the 4 conditions the CS-TS pair was delivered over the left hemisphere. The TS was delivered to the first dorsal interosseous (FDI) hotspot within M1 at an intensity necessary to evoke an MEP of ~ 1 mV during the rest and active conditions. Preliminary analysis on the data suggests that during rest, BA 5 exerts a net inhibitory effect on M1 at long latencies (30 and 40 ms). However, during active contraction, BA 5 exerts an early facilitation of M1 (6 â€“ 10 ms), and a late disinhibition (30 and 40 ms). These effects are observed with a CS intensity of 90% and not at 110%. The higher CS intensity resulted in identical effects between rest and active conditions.
POSTER #18 Alterations of Cortical and Hippocampal Network Activity In MeCP2-Deficient Mice Jennifer D'Cruz, University of Toronto, IMS graduate department, James Eubanks, PhD, Toronto Western Research Institute, University of Toronto.
Intractable epilepsy remains one of the top issues affecting the quality of living in Rett children. While several MeCP2-deficient mouse models of Rett Syndrome have been established, only minimal information exists on how the loss of MeCP2 affects brain network activity. To address this issue, in vivo recordings of the hippocampus and somatosensory cortex of Mecp2-deficient mice were taken during exploration, immobility, and sleep. The frequency of hippocampal theta rhythm oscillations during exploration was significantly attenuated in Mecp2-deficient mice. Further, Mecp2heterozygous mice displayed spontaneous, brief, epileptiform-like spike and wave discharges (SWD) in the somatosensory cortex in the immobile state. Similar SWDs were observed in the hippocampus and somatosensory cortex of one of the four Mecp2null mice recorded. Collectively, these findings indicate that a deficiency of MeCP2 in mice leads to subtle alterations in the normal brain wave activity with similarities to what has been observed clinically in Rett syndrome patients.
POSTER #19 The Effects of Microinfusions of Oxytocin into the Nucleus Accumbens Shell on Maternal Memory in Female Sprague-Dawley Rats Tracey M. D’Cunha, B.Sc. Student, University of Toronto Mississauga; Frederic Lévy, Ph.D., H.D.R., Intra-Cnrs-Université de Tours-Haras Nationaux; Alison S. Fleming, Ph.D., F.R.S.C., University of Toronto Mississauga. The maintenance of maternal behaviour is dependent on prior maternal experience. Females rats with prior maternal experience display shorter latencies to respond to pups compared to females with no prior experience. This phenomenon is referred to as the “maternal experience effect” or “maternal memory”. Recent evidence has indicated that oxytocin receptors in the nucleus accumbens (NA) shell play a role in the consolidation process of maternal memory. The current study investigated the effects of microinfusions of oxytocin into the NA shell on maternal memory. At parturition female rats were infused with either a low or high dose of oxytocin, and a control group was infused with artificial cerebrospinal fluid. Results indicated a trend that oxytocin decreases the latency to display maternal behaviour. Oxytocin also affected the quality of the maternal behaviours displayed. Females administered oxytocin engage in hovering and licking behaviours for longer durations compared to females administered a vehicle control. Females administered oxytocin also display increased frequencies in pup retrieval during testing. The results suggest that oxytocin receptors in the NA shell are important for the consolidation process of maternal memory, and may also affect the quality of maternal behaviours that are displayed.
POSTER #20 The effect of nicotine and ethanol on CYP2B6 in African Green monkeys Charmaine S. Ferguson, PhD Student, Department of Pharmacology and Toxicology, University of Toronto; Sharon Miksys, PhD, Centre for Addictions and Mental Health (CAMH); Rachel F. Tyndale, PhD, University of Toronto and CAMH CYP2B6 metabolizes a variety of substrates including clinical drugs, drugs of abuse, endogenous substrates and toxins. We have detected higher levels of CYP2B6 in the brains of human smokers and alcoholics compared to non-smoking non-alcoholics. Increased levels of CYP2B6 may cause altered sensitivity to centrally acting drugs, neurotoxicity and contribute to nicotine/alcohol addiction. The objective of this study was to evaluate the effect of chronic ethanol and nicotine, separately and in combination, on CYP2B6 protein levels in monkeys. African green monkeys were used because they offer a good representation of human CYP expression and activity and voluntarily consume alcohol at levels comparable to human consumption. Forty monkeys were randomized into four groups. Groups 1 and 2 were allowed to self-administer 10% alcohol in sucrose solution while Groups 3 and 4 consumed sucrose solution on the same schedule. Groups 2 and 4 were injected with 0.5 mg/kg nicotine twice a day while Groups 1 and 3 were injected with saline on the same schedule, yielding a no drug control group (3), an alcohol only group (2), a nicotine-only group (4) and an alcohol + nicotine group (1). In the last phase animals received nicotine (or saline) and ethanol (or sucrose) for 3 weeks and daily alcohol consumption and blood ethanol levels were measured. Animals were sacrificed, microsomal and membrane proteins were isolated from liver and brain tissue and CYP2B6 protein levels were assessed by Western blotting. Nicotine induced CYP2B6 protein in the frontal cortex but not in the liver, cerebellum or putamen. Ethanol induced CYP2B6 protein in the liver and putamen but not in the frontal cortex or cerebellum. These results show the contrasting patterns of CYP2B6 induction by nicotine and ethanol in monkey and provide further insight into the role of CYP2B6 in nicotine and alcohol dependence and associated health risks.
POSTER #21 Risk alleles of the serotonin transporter polymorphism predict small hippocampal volumes in major depression Jane A. Foster1,2*, Ph.D., Kaan Yucel1, MD, Ph.D., Edith Kolozsi1,2, B.Sc., Robyn N. MacKenzie1,2, B.Sc., and Glenda MacQueen2,3, MD. Ph.D 1..Department of Psychiatry & Behavioural Neurosciences, McMaster University, Hamilton, ON, 2. Brain-Body Institute, St. Josephâ€™s Healthcare, Hamilton, ON, 3. Department of Psychiatry, University of Calgary, Calgary, AB, Canada
Background. Functional polymorphisms of the serotonin (5-HT) transporter gene (SLC6A4) are associated with risk of major depressive disorder (MDD) and treatment response. Methods. We examined hippocampal volumes and triallelic polymorphisms of the 5-HT transporter in 50 patients with MDD and 50 healthy controls. Results. Our mean age of onset was 23.5 years. In this patient population, patients with the functionally low 5HTTLPR genotypes (Lg/S or S/S) had significantly smaller hippocampal volume compared to healthy controls with the Lg/S or S/S genotype. No significant differences were found between patients and controls with the La/La or La/Lg + La/S genotypes. In addition, an significant association was observed between risk alleles and later cognitive deficits in multiple episode patients. Conclusions. These findings provide important additional evidence that genetic variation in the 5HTTLPR contributes to the variation in hippocampal volume observed in patients with MDD.
POSTER #22 Dexefaroxan reverses cognitive and affective phenotypes in TgCRND8 mice Beverly M. Francis1, Ph.D. student; Jimao Yang, B.Sc.; and Howard T.J. Mount1, 2, Ph.D. Centre for Research in Neurodegenerative Diseases, Departments of Physiology1, and Medicine (Div. Neurology)2, Faculty of Medicine, University of Toronto, ON. Noradrenergic deficits may be key to the pathogenesis and behavioural presentation of Alzheimerâ€™s disease (AD). We assessed monoamine levels and turnover by HPLC and electrochemical detection in the amyloid precursor protein (APP)-transgenic TgCRND8 mouse model of AD. We found that pre-plaque, 4-week-old TgCRND8 mice exhibit selective reductions in noradrenaline in the hippocampus, temporoparietal and frontal cortices, and cerebellum. Analyses in older mice revealed the noradrenergic deficit to be progressive. No reductions were observed in dopamine. However, serotonin and its 5-HIAAA metabolite were increased in the striatum and brainstem of aged plaque-bearing mice. To assess how altered transmitter levels might influence phenotypes, we examined cognition, affect and forelimb coordination. Pre-plaque, 8 week old TgCRND8 mice had significant cortical, short-term memory deficits in an object recognition task. By this age, they also exhibited progressive behavioural despair in a tail suspension test, shown sensitive to antidepressants that increase noradrenergic transmission. At 24 weeks, TgCRND8 mice were less anxious than littermate controls in the zero maze. To test whether the loss of noradrenergic tone in major terminal fields caused these behavioural phenotypes, we examined the effect of replenishing noradrenaline. Dexefaroxan (Pierre Fabre Inc.) enhances noradrenergic transmission by antagonizing presynaptic inhibitory !2-adrenoceptors. Mini-osmotic pumps, delivering dexefaroxan, saline or rivastigmine (Exelon": Novartis Inc.), an acetylcholinesterase inhibitor clinically used in AD, were implanted subcutaneously in 12-week-old mice for 28 days. Both dexefaroxan and rivastigmine ameliorated object memory deficits and behavioural despair. Noradrenaline can affect cortical plasticity by increasing acetylcholine release. Dexefaroxan facilitates this release of acetylcholine by blocking the inhibitory !2-adrenoceptors that are heterologously located on cholinergic terminals. Neither dexefaroxan, nor rivastigmine altered anxiety, a parameter that may depend more upon striatal serotonin levels. In sum, we have shown that noradrenergic deficits precede plaque deposition and behavioural impairment in a robust amyloid-based mouse model of AD. Targeting the noradrenergic deficit early in the disease process may mitigate amyloid-induced functional impairment. Supported by the Ontario Mental Health Foundation
POSTER #23 TAKING THE RISK: EFFECTS OF METHAMPHETAMINE ON SEXUAL BEHAVIOR IN MALE RATS Karla S. Frohmader, PhD Student, Graduate Studies in Anatomy and Cell Biology, University of Western Ontario; Katherine Bateman, B.Sc, University of Western Ontario; Lique M. Coolen, PhD, University of Western Ontario Naturally rewarding stimuli such as sexual behavior and drugs of abuse exert their rewarding and reinforcing effects via the same neural circuit, the limbic system. We recently showed that in male rats, sexual behavior and methamphetamine (Meth) activate the same neurons in some brain areas of the limbic system. However, it is unknown how Meth affects male rat sexual behavior. Interestingly, Meth addicts report having heightened sexual arousal, frequently having numerous sexual partners, and engaging in unprotected sex mostly through loss of inhibitions. Here, we hypothesize that Meth administration will also alter various aspects of rat sexual behavior including risk taking related with sexual behavior. First, the effects of Meth on sexual motivation and performance were tested. Sexually na誰ve and experienced male Sprague Dawley rats were administered 1 of 4 doses (0, 1, 2, or 4 mg/kg s.c.) of Meth (n=8 each) 30 minutes prior to mating. Results show a dose dependent decrease in sexual performance evidenced by reduced percentages of animals that mated and longer latencies to mount, intromit, or ejaculate. Furthermore, sexual experience did attenuate, but not completely ablate, the inhibiting effects of Meth on sexual performance. Next, the effects of acute Meth administration on inhibition of sexual behavior was tested using a sex aversion conditioning paradigm, in which visceral illness induced by lithium chloride (LiCl) was paired with sexual reward. Four experimental groups were included; LiCl unpaired and paired males that received an acute administration of either saline (1 ml/kg s.c.) or Meth (1 mg/kg s.c.) two weeks prior to conditioning (n=10 each). Results show that an acute dose of Meth prior to conditioning impaired learned inhibition of mating in sexually experienced male rats as Meth pre-treated males required more conditioning trials to reach significant inhibition of sexual behavior compared to saline pre-treated paired males. In addition, following nine conditioning trials, all paired males were administered Meth (1 mg/kg s.c.) to determine if the drug was able to override the learned inhibition of sexual behavior. Indeed, Meth administration resulted in increased percentages of paired males that mated, although significance for sexual inhibition was only disrupted in meth, but not saline pre-treated paired males. Together these data support the use of the male rat to study the mechanisms by which Meth administration in human results in risk taking related to sexual behavior. Supported by NIH R01 DA14591 to LMC
POSTER #24 Altered Perception affects action in hypnoticomotor tasks Victoria Galea, PhD, School of Rehabilitation Science, McMaster University A large percentage of classic hypnotic effects involve alterations in the perception of control of motor movements. Two typical challenge tasks under hypnotic suggestion specifically an arm stiffness task and an arm rigidity task were tested. An adaptation of the method proposed by Rudroff et al (2007) was used to analyze the electromygraphic (EMG) profiles for the existence of significant bursts throughout the whole task and during the time of the challenge in particular. The driving hypothesis for this study was that burst activity in the prime movers of the shoulder or elbow would decrease (or not change) during the challenge portion if the primary motor cortex was not engaged in the action demanded by the challenge. Twelve subjects who scored 9 and above (range 9-12) on the HGSHS:A, a standardized test of hypnotizability, were used in this study. These data were compared to those from 8 unhypnotized subjects who were read the same script and encouraged to try to bend the elbow when challenged during the stiffness task. EMGâ€™s from Upper Trapezius, Pectoralis Major, Anterior Deltoid, Posterior Deltoid, Biceps Brachii and Triceps Brachii were analyzed. The existence of burst activity was assessed via custom software (Labview Systems) using decision algorithms based on visual observation of activation patterns. In 7 of the 12 subjects bursts were either non-existent or too short (less than 300 ms) to be considered volitional during the tasks. In contrast unhypnotized subjects showed considerable evidence of bursts that were at least 1500 ms long, in all muscles but primarily in those crossing the elbow. Evidently the suggestion of experiencing a very stiff arm and then challenged to try to bend it or being told that their arm was immobile and being asked to move it results in varying engagement of the primary motor cortex.
POSTER #25 Spatial analysis of olfactory bulb activity in the sea lamprey Warren W. Green*1, Sana Ahmed1, Dominique Derjean2, Réjean Dubuc2, Barbara S. Zielinski1. 1. Department of Biological Sciences, University of Windsor, Windsor, Canada. 2. Centre de Recherche en Sciences Neurologiques, Département de physiologie, Université de Montréal, Canada. The sea lamprey (Petromyzon marinus) uses olfaction to detect a variety of odours that induce movement and searching behaviours. The peripheral olfactory organ of sea lamprey is comprised of the main olfactory epithelium (MOE) and the accessory olfactory organ (AOO). Neural connections from the AOO project solely to the medial region of the olfactory bulb (OB) while projections from the MOE are distributed to all glomerular regions. Our goal is to examine odour input specificity and processing in the OB of sea lamprey as it relates to behaviour. To that effect, we examined the morphological characteristics of the MOE and AOO as well as the organization of odour processing in the OB. The peripheral olfactory organ of metamorphic, parasitic, and migratory adult lamprey was dissected, sectioned, and the relative area of the MOE and AOO was calculated. The proportion of AOO in the peripheral olfactory organ increased from 22% in metamorphic lamprey to upwards of 30% in parasitic and migratory adult sea lamprey indicating an increase in input from the AOO to the OB during adult life stages. Additionally, multi-unit action potentials in response to odours were recorded in the OB of the live ex vivo brain of parasitic and migratory adult sea lampreys. Action potential frequency increased in the medial OB in response to bile acids and the lamprey pheromone 3KPZS. Action potential frequency also increased in the lateral and ventral-lateral OB in response to basic amino acids and 3KPZS, respectively. These results indicate that odour input and processing in the medial OB is important for responding to behaviourally-relevant odours. Funding provided by the GLFC and NSERC.
POSTER #26 The effect of acute stress on reacquisition of heroin self-administration in rats Stephanie Grella, M.A.Student, Neuroscience & Applied Cognitive Science, University of Guelph; Francesco Leri, PhD, Associate Professor, University of Guelph Abstract: Stress is a major precipitant of drug relapse. In animals, stress enhances acquisition of intravenous self-administration and reinstates lever-pressing after extinction. It is known that animals will reacquire self-administration after a period of abstinence, but it is not known whether stress can change the amount or pattern of drug intake when the drug is made available again after a period of extinction. Thus, this study employed a reacquisition model of intravenous self-administration to examine the effect of acute foot shock stress on reacquisition to heroin self-administration in male Sprague Dawley rats. Animals were trained to selfadminister heroin (0.05 mg/kg/infusion) on an FR1 schedule of reinforcement in the presence of a discriminative stimulus signaling drug availability. After a period of withdrawal and extinction, animals were assigned to one of four shock intensity groups (0.0 mA, 0.5 mA, 0.8 mA, 1.5 mA) and given 15 minutes of intermittent foot shock (controls were exposed only to the noise of the shock apparatus) just prior to the test of reacquisition of heroin self-administration. A separate study conducted on animals lever pressing for sucrose showed that foot shock stress at the highest intensity (1.5 mA) significantly decreased lever pressing. This study found that foot shock stress at all three intensities (0.5 mA, 0.8 mA, and 1.5 mA) decreased heroin intake during reacquisition. These results suggest that acute stress can rapidly alter the reinforcing properties of heroin and therefore alter heroin intake. Additional studies are required to establish the direction of this possible modulation, and its impact on propensity to reacquire a drug-seeking habit.
POSTER #27 Tritium-labelled estradiol in male urine binds in the uterus and brain of inseminated female mice (Mus Musculus): Implications for the Bruce effect Adam C. Guzzo, Ph.D. Student; Robert G. Berger, Ph.D. Student; Denys deCatanzaro, Ph.D. Dept. of Psychology, Neuroscience & Behaviour, McMaster University Novel male mice actively direct their urine at nearby inseminated females, and this urine can disrupt early pregnancy, a phenomenon known as the Bruce effect. Since intrauterine implantation of blastocysts is highly sensitive to exogenous estrogens, and male mouse urine contains unconjugated 17"-estradiol and other steroids, the capacity of males to disrupt early pregnancy could be mediated by steroids in their urine. We implanted outbred male mice with micro-osmotic pumps containing tritium-labelled estradiol (3H-E2) and collected their urine both before and after a 5-day exposure to recently inseminated females. We were able to recover 3HE2 in the collected urine, with greater radioactivity in pre-exposure samples. Similarly, 3H-E2 intraperitoneally injected into males was recoverable in their urine. We then intranasally administered 3H-E2 to inseminated females two days after the detection of a vaginal plug. Radioactivity was detected in diverse tissue samples from these females. Uterine and ovarian tissue samples were significantly more radioactive than were samples of the olfactory bulb, mesencephalon plus diencephalon (MC+DC), and cerebral cortex. Finally, we intranasally administered urine from males given 3H-E2 to inseminated females. Radioactivity was detected in the uterus, olfactory bulbs, and MC+DC of these females. Taken with evidence that males deliver their urine to the nasal area of females, these results indicate that male urinary estradiol arrives in female tissues, including the uterus, where it can directly disrupt intrauterine implantation of blastocysts. This research was supported by grants from the Natural Sciences and Engineering Research Council of Canada to D. deCatanzaro.
POSTER #28 BRAIN DERIVED NEUROTROPHIC FACTOR-OPPOSITE STRAND EXPRESSION AND ITS POTENTIAL REGULATORY ROLE IN COGNITIVE IMPAIRMENT: WORK IN PROGRESS Aaron Hackett, B.Sc. Student, Departments of Biology and Psychology; Margaret Fahnestock, Ph.D., Department of Psychiatry and Behavioural Neurosciences, McMaster University Brain derived neurotrophic factor (BDNF) is a member of a class of proteins known as neurotrophins which are required for neuronal cell survival and differentiation. BDNF in addition is known to regulate neurotransmitter synthesis, long term potentiation and synaptic function. Interestingly, BDNF mRNA and protein levels are decreased in the hippocampus and cortex as well as in basal forebrain cholinergic neurons in subjects with Alzheimerâ€™s disease compared to controls. Decreases in BDNF occur early in the disease and are correlated with the degree of cognitive decline, suggesting that deficits in this neurotrophic factor can be linked to cognitive impairment. Recently, it has become apparent that mRNA transcripts derived from the opposite (antisense) strand of the BDNF gene (BDNF-OS) may serve as a potential regulatory mechanism for BDNF production. In the current study, we are investigating BDNF-OS expression levels in post mortem cortical tissue from subjects with differing degrees of cognitive impairment using real-time qRT-PCR quantification. Primers amplifying the 12 known BDNF-OS transcripts have been generated and standard curve development is in progress. The results of this study may serve as the first evidence implicating antisense regulation of a neurotrophin - a concept which may be applicable to multiple disorders with associated dysregulation of neurotrophic factors.
POSTER #29 Ethanol Preference in B6 Strain Mice Is Reduced by M5 Muscarinic Receptor Knockout or Naltrexone, but Reversed by Food Deprivation or Long-Term Ethanol Exposure. Robert Hastings, Ken Euler, John Yeomans University of Toronto, Department of Psychology B6 strain mice drink more ethanol than water, and so are useful for studying genetic bases of alcoholism. The opiate antagonist, naltrexone, reduces ethanol intake in alcoholics and B6 mice, and is an FDA-approved therapy for alcohol dependence. Previously, we found that the M5 muscarinic receptor is critical for morphine-induced dopamine release, for the dopaminedependent part of morphine-induced locomotion and for naltrexone inhibition of locomotion in B6 strain mice (Steidl & Yeomans, 2009). Here we test whether the M5 muscarinic receptor is involved in ethanol preference or naltrexone inhibition of ethanol preference, using a two-bottle choice test (i.e. ethanol vs. water). Wild-type B6 mice drank 50-80% more ethanol as M5 knockout mice, following saline or no injection, without differences in water consumption. Naltrexone (5 mg/kg i.p.) reduced ethanol preference in wild-type mice to the same level as M5 knockout mice, without changing ethanol preference in M5 knockout mice. This indicates that the opiate-receptor-dependent part of ethanol preference is mediated by the M5 receptor, but that ethanol preference in B6 mice is also mediated, in part, independent of opiate receptors and M5 receptors. Conditioned place preference for opiates is altered by food deprivation or opiate dependence (Nader et al., 1998). Therefore, we tested whether ethanol preference in B6 mice was altered similarly by deprivation and dependence. After 18 hours food deprivation, ethanol intake increased by 50% in M5 knockout mice, but not in wild-type mice. Similarly, 14 more days testing ethanol preference gradually reduced the difference between M5 knockout and wild-type mice. These results suggest that food deprivation or long-term ethanol exposure switches the effect of M5 muscarinic receptor deletion. These results are consistent with the Laviolette et al. (2004) model of a switch in opiate systems after deprivation and opiate dependence, and with data on opiate-induced locomotion in M5 knockout mice (see poster by Lee et al.). (Suppported by CIHR and OMHF grants to JY)
POSTER #30 OBSESSIVE-COMPULSIVE DISORDER AS A DYSFUNCTION OF SECURITY MOTIVATION. Andrea Hinds, PhD Candidate, Graduate Studies in Neuroscience; Henry Szechtman, PhD, McMaster University; Michael Van Ameringen, MD, McMaster University, Catherine Mancini, MD, McMaster University; Erik Woody, PhD, University of Waterloo A recent theory (Szechtman & Woody, Psychol Review, 111:111-127, 2004) posits a Security Motivation System (SMS) activated by potential, rather than by imminent, threat to the individual. The SMS coordinates motor activity that probes the environment for danger and includes precaution behaviors such as checking (eg, for the presence of predators) and cleaning (for infestation by germs, etc), and induces also an affective phenomenological cue of potential danger that is experienced as anxiety. The production of these species-typical behaviours is thought to be essential for the effective termination of an activated SMS and subsequent decrease in anxiety. Investigation of a physiological measure of the SMS â€“ heart rate variability (HRV) â€“ demonstrated elevation of anxiety after exposure to a high contamination threat stimulus which persisted until performance of appropriate threat-removal behaviours (in this case, hand washing). We further theorized that disturbance in the normal function of the SMS produces the characteristic symptoms of Obsessive-Compulsive disorder (OCD). Under this model, participation in SMS-terminating behaviours is insufficient to return the system to baseline; thus, individuals afflicted with OCD were predicted to display prolonged anxiety after exposure to contamination stimuli, despite participating in hand washing. We report here on a paradigm to test the expected results. In preliminary trials, participants diagnosed with OCD contacting a stimulus which appeared contaminated (diapers appearing wet and soiled) demonstrated an increase in anxiety that was comparable to controls. After hand washing, anxiety, as measured by HRV, returned to baseline in controls, indicative of SMS termination. This decrease in anxiety was incomplete in OCD patients. These trends obtained in the preliminary study provide support for the Security-Motivation theory of OCD, and suggest that dysfunctional termination of the SMS after participation in motivated security behaviours is associated with the compulsions and elevated anxiety characteristic of OCD. Supported by CIHR MOP134450.
POSTER #31 Method of Analysis of Real-time PCR that is Independent of Efficiency Determination Kwokyin Hui, PhD; Abigail Fernandes, Undergraduate Student; Anthony Senzel, MSc; and Zhong-Ping Feng, MD, PhD, Department of Physiology, University of Toronto. Quantative/real-time reverse-transcription PCR, or qRT-PCR, is a powerful experimental method widely used in the quantification of gene expression levels from tissues and cells samples. Its high detection sensitivity resides in the exponential PCR amplification reaction, which also increases the likelihood of detecting contamination. The process from mRNA isolation to PCR amplification and measurement is laid with many sources of instrumental and experimental variation, including the imperfect PCR amplification efficiency, non-specific priming and primer-dimers, and variations in sample quantity. Various methods have been used to reconcile these problems; however, each of them has their own short-comings. In this study, we examined the feasibility of using cross-correlation analysis help resolve some of the pitfalls of qRT-PCR. In particular, we examined the effects of various changes in experimental conditions (PCR efficiency, threshold of qRT-PCR detection, changes in relative gene expression, and interdependencies of the expression of two genes) on plots of cycle threshold values between genes. Cycle threshold values represent the raw output estimates of transcript quantity based on the number of cycles required to amplify the transcript up to a threshold quantity. From these plots, we found that the relative efficiency between two genes is an important determinant in deciding feasibility of using the simpler DDCT method to analyze the data, and the cycle threshold values should be kept constant for each gene to prevent inadvertent conclusions in relative gene expression. Furthermore, these simple plots could be used to indentify clear outliers that may be due to experimental error and the presence of treatment effects and genegene interactions. As proof of principle, we present this method in the analysis of experimental data from a variety of samples, including ganglial transcriptomes of the snails Lymnaea stagnalis following aversive operant conditioning and yoked treatment and transcriptomes from cultured rat preparations. Based on our findings, we propose a strategy which utilizes crosscorrelation plots as a rapid and easy method to identify (1) outliers, (2) treatments/conditions which potentially regulate gene expression, and (3) follow up strategies that can be used for more analytical and detailed analyses. Our methodology will streamline qRT-PCR for gene expression profiling. This study is supported by the Canadian Institutes of Health Research (CIHR).
POSTER #32 THE BIOLOGICAL ACTIVITY OF PRONGF IS DETERMINED BY THE RELATIVE LEVELS OF TRKA AND P75NTR RECEPTORS Maria S. Ioannou1, Raheleh Masoudi, Ph.D.2, Margaret Fahnestock, Ph.D.3 1
M.Sc. Student, Neuroscience Graduate Program; 2Department of Pathology and Molecular Medicine, McMaster University; 3Department of Psychiatry and Behavioural Neurosciences, McMaster University. Nerve growth factor (NGF) is a molecule that affects cell survival, regulation and differentiation of both central and peripheral nervous system neurons. NGF is initially synthesized as a precursor, proNGF, which was recently shown to exhibit biological activity. However, the biological properties of proNGF have been the subject of great controversy: specifically whether proNGF is neurotrophic or apoptotic. Both NGF and proNGF bind to two receptors, the highaffinity TrkA receptor which is responsible for cell survival and differentiation, and p75NTR, the common neurotrophin receptor which can mediate apoptosis. It is known that the ratio of TrkA to p75NTR can determine whether mature NGF signals cell survival or death. We propose that the ratio of TrkA to p75NTR also determines the fate of cells treated with proNGF. We used growth conditions, siRNA and knockouts to modulate TrkA levels in PC12 cells expressing both TrkA and p75NTR receptors. We found that although proNGF is neurotrophic for primed PC12 cells expressing high levels of TrkA and moderate levels of p75NTR, proNGF causes cell death in unprimed PC12 cells expressing lower levels of TrkA and higher levels of p75NTR, while NGF rescues these cells from death. We also found that when TrkA levels are reduced in PC12 cells using siRNA, proNGF becomes apoptotic while mature NGF does not. Finally, we found that proNGF induces more apoptosis in PC12nnr5 (a cell line which expresses no TrkA) than NGF or medium alone. Re-expression of TrkA in PC12nnr5 cells restores proNGF and NGF neurotrophic activity. Thus, we have shown that the biological activity of proNGF can be altered by modulating the relative levels of TrkA and p75NTR: in cells with a high ratio of TrkA to p75NTR proNGF is neurotrophic, while proNGF is apoptotic for cells with a low ratio of TrkA to p75NTR. We attribute the difference in activities between proNGF and NGF to their difference in relative binding affinities: proNGF has a higher affinity for p75NTR while NGF has a higher affinity for TrkA. In the presence of low levels of TrkA proNGF can signal apoptosis via p75NTR, whereas NGF is neurotrophic unless TrkA is eliminated. ProNGF is implicated in various neurodegenerative diseases, and therefore elucidating the conditions in which proNGF signals cell death or cell survival will aid our understanding and help create therapeutic strategies for these diseases.
POSTER #33 AUDITORY CORTICOFUGAL PROJECTIONS TO THE AUDITORY THALAMUS AND THE AUDITORY MIDBRAIN IN THE RAT Lina Jamal, Undergraduate Student; Huiming Zhang, Ph. D., Department of Biological Sciences, University of Windsor. The auditory cortex (AC) is the highest neural structure in the hierarchical mammalian auditory system and it plays a major role in hearing. The AC receives ascending projections from the thalamic auditory structure the medial geniculate body (MGN) and provides corticofugal descending projections to innervate subcortical auditory structures. Major targets of corticofugal projections include the MGN and the midbrain structure the inferior colliculus (IC). Cortical neurons innervating the MGN and IC are widely distributed in the primary as well as other areas of the auditory cortex. Previous studies have revealed that corticofugal projections to the MGN (i.e., corticothalamic projections) are from pyramidal neurons in the layers V and VI of the AC. Corticofugal projections to the IC (i.e., corticocollicular projections) are from pyramidal neurons in the layer V of the AC. It is yet to be found whether neurons in the layer V of the AC provide collateral projections to innervate both the MGN and the IC. Findings related to this question will help us understand the role of the AC in regulating neural responses in the MGN and IC. We conducted tract-tracing experiments in Wistar rats to address this question. Two retrograde tract tracers, Fluorogold and Texas Red dextran, were injected respectively into the IC and the MGB on the right side of the brain. Rats were euthanized and fixed after a survival period of 7 days. Brains were sectioned and labeled neurons in the AC were examined using a fluorescent microscope and a digital imaging system. Following an injection of Texas Red dextran into the MGB, neurons labeled by the tracer were found in the layer V and layer VI of the ipsilateral auditory cortex. These neurons were distributed in the temporal areas 1, 2, and 3. Following an injection of Fluorogold into the IC, neurons labeled by the tracer were found in the layer V of both the ipsilateral and the contralateral auditory cortices. The number of labeled neurons was larger on the ipsilateral than the contralateral side. On both two sides, labeled neurons were distributed in the temporal areas 1, 2, and 3. These results confirmed previous findings regarding the descending projections from the auditory cortex to the MGB and the IC. In addition to neurons labeled by a single tracer (i.e., Texas Red dextran or Fluorogold), there was a small group of neurons labeled by both two tract tracers. These neurons were also distributed in the temporal areas 1, 2, and 3. It is noted that corticocollicular projections pass through the MGN en route to their target in the IC. Therefore it is likely that labeling of fibers en passant in the MGN by Texas Red destran might have contributed to the double labeling of neurons in the AC. Our results indicate that there are two separate groups of neurons in the layer V of the AC respectively innervating the MGB and the IC. Few if any neurons in the layer V of the AC innervate the two subcortical structures simultaneously. These results suggest that the layer V of the AC provides two different sets of modulations to neurons in the MGN and the IC. Research supported by NSERC of Canada and the University of Windsor.
POSTER #34 Conditioned locomotion and structural plasticity in the amygdala after repeated cocaine administration: assessment after brief and extended drug-free periods Sarah A Johnson, PhD Student, Dept of Psychology and Program in Neuroscience, University of Toronto; Saadia Sediqzadah, BSc Student, University of Toronto at Scarborough; Franca M Placenza, PhD, University of Toronto at Scarborough; Suzanne Erb, PhD, Centre for the Neurobiology of Stress, Dept of Psychology and Program in Neuroscience, University of Toronto. The behavioural and neuroanatomical correlates of drug withdrawal and craving remain relatively unexplored. It has been shown that non-reinforced operant responding for drug in rats that previously self-administered cocaine increases over extended drug-free periods, which is suggestive of an incubation of craving; however, it is not known whether other conditioned responses to drug-paired contextual cues, such as those elicited by non-contingent exposures to drug, also incubate in this manner. The amygdala is known to play an important role in appetitive cue conditioning, via connections with the ventral striatum, and may therefore be a locus for structural plasticity in this context. The present study had two aims: (1) to determine whether conditioned locomotor activity persists and/or becomes more pronounced after an extended drug-free period, and (2) to characterize the effects of repeated cocaine administration on dendritic branching in the amygdala after brief and extended drug-free periods. Male Wistar rats received injections of either cocaine-HCl (30 mg/kg, i.p.) or vehicle once a day for 6 days. Injections were administered in behavioural monitoring chambers, where locomotor activity was recorded for 30 minutes. The saliency of the contextual cues was enhanced by applying peppermint extract to the chambers before daily conditioning sessions. Conditioned locomotion was assessed either 1 day or 6 weeks after the final drug injection, by re-exposing rats to the chambers and peppermint odour. Rats were sacrificed 24 hours after testing, and brain tissue was collected for Golgi-Cox impregnation. Neurons from the basolateral (BLA) and Central (CeA) nuclei of the amygdala were reconstructed using the NeuroLucida software suite (MicroBrightField, Inc), and structural plasticity of these neurons was assessed based on changes in dendritic length and branch point number. Repeated administration of cocaine induced comparable levels of conditioned locomotion after 1-day and 6-week drug-free periods. These behavioural changes corresponded to comparable, and subtle, changes in dendritic complexity in the amygdale at both withdrawal times. Specifically, repeated cocaine increased the number of branch points on basal dendritic arbours in BLA after 1 day of withdrawal, and this increase persisted after 6 weeks of withdrawal. Neuronal dendritic structure in CeA, on the other hand, was not altered by this cocaine administration paradigm. Our results suggest that the conditioned locomotor response to drug-paired contextual cues does not incubate over extended drug-free periods. Further, neurons in the BLA, a structure known to play a role in appetitive cue conditioning, showed increased dendritic complexity both 1 day and 6 weeks after cocaine administration, perhaps reflecting the formation and maintenance of associations between drug-paired cues and the rewarding properties of cocaine.
POSTER #35 The effects of an indirect cannabinoid agonist on social approach and object placement in male CD-1 mice. Jung*1, H., Orth*2, C., Bannon3, D. R., & Choleris4, E. * Jung and Orth have contributed equally to the research presented here 1 Undergraduate student, Department of Biomedical Sciences, University of Guelph 2 B.A.S., Department of Psychology, University of Guelph 3 MA Candidate, Department of Psychology, University of Guelph 4 Ph.D., Department of Psychology, University of Guelph The recently discovered cannabinoid system has been shown to be involved in numerous behaviours in rodents. These include activity, feeding, anxiety, depression, pain responses and social interactions. In order to better understand the involvement of the cannabionoid system in social behaviour we investigated the effects of the indirect cannabinoid agonist URB597, a fatty acid amide hydrolase (FAAH) inhibitor, in social approach and non-social behavioral tests. FAAH is responsible for the breakdown of the endogenous cannabinoid anandamide, and its inhibition results in prolonged and increased anandamide activity in already active synapses. We chose URB597 because it has been previously shown to affect social behaviours in rodents (e.g. play). We used 2-3 months old male CD-1 mice randomly assigned to one of five treatment groups; uninjected, vehicle-injected (45% cyclodextrin) as well as three drug conditions; 0.05, 0.10, 0.40 mg/kg URB597. All injections were administered intraperitoneally 1 hr prior to behavioural testing. Social approach was examined in the home cage where individually housed experimental mice were habituated to the presence of two empty perforated plexiglass cylinders for 5 min before receiving a 15 minute test where they were presented with a choice between two perforated cylinders containing either a social stimulus or a non-social olfactory stimulus. The social stimulus was a castrated mouse, while the non-social stimulus was a drop of diluted 1% vanilla odour. Spatial learning was tested with the object placement test in which mice were habituated to two objects in their home cage over a series of four 5 min exposures with 15 min intervals. On a fifth 5 min test one of the objects was placed in a novel location. Direct investigation of the social and non-social stimuli as well as non-stimulus directed behaviours (e.g. cage exploration) were recorded and scored using computer aided observations. Preferences for a specific stimulus were expressed as a score in which the amount of time spent investigating a stimulus was divided by the total amount of time spent investigating both stimuli. Results show that in the social approach test the mice that had received URB597 at 0.40 mg/kg had lower social approach preference scores than the mice in the vehicle control group. This was reflected also in the mice of the 0.40 mg/kg group spending less time investigating the social stimulus than controls. Other behaviours were only minimally affected. In the object placement test no significant preference for the novel spatial stimulus was found in any of the groups. Overall we found that an enhancement of the activity of the cannabinoid system obtained with an indirect agonist has selectively reduced the natural mouse tendency to prefer to investigate a social rather than a non-social stimulus in the social approach test, while having no effects on a spatial version of the object recognition test. Thus, it appears that the cannabinoid systemâ€™s involvement in the regulation of social behaviours may be relatively specific.
POSTER #36 Attraction of Female Round Gobies to Steroids Released by Males. Kereliuk, M.R.1, Katare, Y.1, Tierney, K1., Laframboise, A.1, Scott, A.P.2, Loeb, S.J.3 & Zielinski, B.1 1: Dept. of Biology, University of Windsor, Windsor, ON; 2: CEFAS, Weymouth, Dorset, UK; 3: Dept. of Chemistry & Biochemistry, University of Windsor, Windsor, ON The objective of this study is to evaluate the female chemoattractant property of isolates derived from male urine or from water previously occupied by male round gobies, Neogobius melanostomus, which is an invasive fish species to the North American Great Lakes. Reproductive (RF) or non-reproductive phase female (NRF) round gobies were placed in isolated 5-L flow-through tanks and presented with odours via the water inflow after an acclimation period. The behaviour of the fish was recorded then analyzed. Swimming velocity and the amount of time spent near the odour inflow was determined. Neither parameter was affected by the delivery of vehicle blanks. The RF increased the time spent near the odor source when presented with urine collected from males previously injected with GnRH, and by fish water excluding urine. Both RF and NRF were attracted by methanol extracts of male-scented water. NRFs increased swimming velocity toward and the time spent near an isolate of malescented water containing the steroid 11-oxo-etiocholanolone (11-oxo-ETIO), however RF showed an avoidance swimming reaction to this fraction. In contrast, both RFs and NRFs spent greater time near the inflow of an isolate containing an unknown conjugate of 11-oxo-ETIO. These studies demonstrate that females can exhibit reproductive-state specific attraction responses to steroids released by male round gobies, including 11-oxo-ETIO and an unidentified conjugate. We are working towards identifying the compounds responsible for this activity.
POSTER #37 Expression of HSP70 Family Members in Cultured Neuronal Cells Sam Khalouei, PhD Student; Ari M. Chow, PhD; Ian R. Brown, PhD, Center for the Neurobiology of Stress, University of Toronto at Scarborough In response to a range of stressful stimuli, cells exhibit a highly conserved heat shock response in which protein synthesis is down-regulated and transient induction of a set of heat shock proteins (Hsps) takes place. Hsps protect the cell by facilitating the repair of misfolded proteins that arise due to stress. They are comprised of both constitutive and inducible members and based on their molecular weights are divided into several families including HSP110, HSP90, HSP70, HSP60, HSP40 and small HSPs. The HSP70 family has been under extensive study in the past two decades due to its vital role in cytoprotection. HSP70 family members have been shown to confer protection to the nervous system. Neurodegenerative diseases (NDs) such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis (ALS), and Huntington’s disease, are characterized by misfolding and aggregation of proteins and are collectively referred to as 'protein misfolding disorders'. Recent studies suggest that Hsps can protect against neurodegeneration by modulating misfolded and aggregation-prone proteins. Therefore, inducing the expression of Hsps in neurons is a promising avenue for combating NDs. The goal of the current study is to monitor the cellular localization of HSP70 family members in established neuronal cell lines under control and stress conditions. In order to monitor this localization using fluorescence microscopy, we fused a strong detectable marker, namely the yellow fluorescent protein (YFP), to the N-terminus of the three members of the HSP70 family. The neuronal cells were transfected with plasmids coding for the fusion proteins. The transfected cells were then selected for transgene expression using the G418 antibiotic and subsequently subjected to Fluorescence Activated Cell Sorting (FACS) to obtain stable cell lines. Visualization of the tagged proteins by fluorescence microscopy revealed a granular distribution of the fusion heat shock proteins.
POSTER #38 CYP2B Is Induced In The Rat Brain By Chronic Nicotine Treatment: Induction Time Course Jibran Y. Khokhar, Ph.D Student*, Sharon Miksys, Ph.D., and Rachel F. Tyndale, Ph.D. Centre for Addiction and Mental Health and Department of Pharmacology, University of Toronto, Toronto, Canada Background: CYP2Bs are found in hepatic and extra-hepatic tissues such as the brain. CYP2B1/2 are the major nicotine-metabolizing enzymes in rats. Human CYP2B6 can also metabolize nicotine as well as other drugs and neurotransmitters such as bupropion, efavirenz, ecstasy, and serotonin. CYP2B6 is higher in brains of human smokers, and chronic nicotine treatment increases rat and monkey brain CYP2B. Rat CYP2B is significantly induced by nicotine in the brainstem, frontal cortex, striatum, and olfactory bulb, but not in the liver. Since the time of peak induction and the duration of induction are unknown, we investigated the timecourse of rat brain CYP2B. Methods: Rats were treated daily with 1 mg base/kg, s.c. nicotine or saline, for 7 days, and sacrificed at 30 minutes to 24 hours after the last dose. Brain regions were assayed for CYP2B protein levels using western blotting, and for CYP2B1 RNA using realtime PCR. Results: We tested the induction in two regions, brainstem and frontal cortex, where we had previously seen elevations at 4 hr and one region, cerebellum, where we had not. In both brainstem and frontal cortex CYP2B levels were significantly elevated to maximal levels relative to saline treated animals. The induction in both regions remained elevated for at least 24 hr after the last nicotine injection. In contrast, the cerebellum showed virtually no effect of nicotine at any time-point. CYP2B1 RNA levels in the brainstem were also significantly elevated, tested at 30 minutes and 24 hours after the last treatment (6- and 4.5-fold, respectively), while no change was seen in the CYP2B1 RNA levels in the cerebellum consistent with the protein levels. Diurnal differences in the expression and induction of brain CYP2B by nicotine were also observed. Conclusion: We have shown that nicotine can selectively induce CYP2B protein levels among rat brain regions and that the increases were long lasting and involved transcriptional regulation. These results also suggest that nicotine is one component of cigarette smoke that contributes to the higher levels of CYP2B6 seen in human smokers. Active and passive smokers and people undergoing nicotine therapy might have higher brain CYP2B levels and increased in-situ metabolism of centrally acting CYP2B substrates such as nicotine, ecstasy, and bupropion. This change in brain metabolism could result in altered therapeutic response, brain levels of neurotransmitters and/or neurotoxicity.
Funded by: CIHR MOP14173, Canada Research Chair-RFT, Strategic Training Fellowship in Tobacco Use in Special Populations-JYK, CAMH. Key Words: CYP2B, Brain, Nicotine
POSTER #39 Autobiographical memory in recurrent major depressive disorder and bipolar disorder: Moderating effects of emotion and mood state Matthew King1,2, MSc student, Arlene MacDougall2, PGY(4), MSc student, Brain Levine3, PhD, Glenda MacQueen1,4, MD/PhD, Margaret C. McKinnon1,2 1
Mood Disorders Program, St. Joseph's Healthcare; Department of Psychiatry and Behavioural Neuroscience, McMaster University; 3 Rotman Research Institute, Baycrest Centre; 4 Department of Psychiatry, University of Calgary
Background: Autobiographical memory (AM) for life events in patients with major depressive disorder (MDD) has been examined in a large series of studies. These studies reveal overgeneralization, by which AM comprises primarily factual or repeated information as opposed to details specific in time and in place. This pattern is similar to that reported in other disorders involving fronto-temporal dysfunction, including post-traumatic stress disorder, medial temporal lobe amnesia, and prefrontal damage and in healthy aging. Preliminary evidence suggests that patients with bipolar disorder (BD) may also exhibit AM deficits similar to those observed in patients with MDD. We examined whether this lack of AM specificity in mood disorders is based on the impoverishment of episodic or semantic elements of memory of a combination of both. We also assessed the moderating impact of emotional valence and of mood state on AM performance in patients with recurrent illness. Methods: Using the Autobiographical Interview, a method shown previously to dissociate the episodic and semantic elements of AM, participants experiencing 3 or more episodes of MDD or BD and their matched controls were asked to recall i) positive, ii) negative and iii)neutral events. A separate sample of participants recalled events that occurred while i) actively depressed, ii) actively manic and iii) euthymic. Results: Overall, patients with MDD recalled fewer episodic details of positive, negative and neutral events than matched controls. By contrast, semantic recall was equivalent between groups for all events tested. Currently depressed patients showed overgeneralized recall, as reflected in a lower ratio of episodic to total details recalled than matched controls; this effect was not observed in MDD patients who were euthymic at the time of testing. Results for the BD sample and for recall of events encoded during depressed, manic and euthymic stats of illness will be presented. Conclusions: MDD is associated with impoverished recollection of emotional and nonemotional events, an effect that may be moderated by mood state. These deficits are likely to extend to patients with BD. Identifying precisely the nature of AM impairment in mood disorders is likely to translate to improvements in the design of treatment interventions focused on AM and its altered function in these conditions. McKinnon, M. C., Nica, E. I., Sengdy, P., Kovacevic, N., Moscovitch, M., Freedman, M., et al. (2008). Autobiographical memory and patterns of brain atrophy in frontotemporal lobar degeneration. J Cogn Neurosci, 20(10), 1839-1853. Svoboda, E., McKinnon, M. C., & Levine, B. (2006). The functional neuroanatomy of autobiographical memory: a meta-analysis. Neuropsychologia, 44(12), 2189-2208.
POSTER #40 Cytokine polymorphisms in people with major depression Edith Kolozsi,1 Robyn MacKenzie,2,3 Glenda MacQueen,3,4 and Jane A. Foster2,4 1. 2. 3. 4.
MSc Student, Medical Sciences Graduate Program, McMaster University Department of Psychiatry & Behavioural Neurosciences, McMaster University Brain-Body Institute, St. Josephâ€™s Healthcare Department of Psychiatry, University of Calgary
Genetic variation accounts for a portion of the variability in cognitive processes, vulnerability to disease, and patient response to treatment. One of the leading approaches to understanding the pathophysiology of MDD is the use of molecular genetics to examine the role of genetic variation. We propose to use this approach, in combination with behavioral assessment and structural neuroimaging, to assess the role of genetic variation in hippocampal volume in patients with MDD and healthy volunteers. We will examine the role of genetic variation in immune genes as immune dysfunction is implicated in the pathophysiology of MDD (Anisman, 2009, Miller, 2009). Both pre-clinical and clinical research points to a role for cytokines in the pathology of MDD; for example, patients with inflammatory or immune disorders have high rates of depression (Cassidy et al., 2002). Atypical cytokine profiles been reported in patients with depression (Cizza et al., 2008), and in animal studies, administration of cytokines induces depressive-like behaviour that can be attenuated by cytokine antagonists and antidepressant drugs (Goshen et al., 2008). We are examining functional polymorphisms in interleukin 6 (IL6) and interleukin-1# (IL1#) genes, specifically IL-6 p-174, IL-6 vntr and IL-1" p+3953 polymorphisms. The functional significance of IL-6 vntr and its impact on protein expression is still to be determined. The IL-6 p174 (C/G) and IL-1" p+3953 (C/T) polymorphisms influence peripheral protein levels. We will determine the role of these cytokine polymorphisms on vulnerability to depression as well as on the structure and function of the hippocampus. Anisman H Cascading effects of stressors and inflammatory immune system activation: implications for major depressive disorder. J Psychiatry Neurosci 34:4-20.2009. Cassidy EM, Manning D, Byrne S, Bolger E, Murray F, Sharifi N, Wallace E, Keogan M, O'Keane V Acute effects of low-dose interferon-alpha on serum cortisol and plasma interleukin-6. Journal of psychopharmacology (Oxford, England) 16:230-234.2002. Cizza G, Marques AH, Eskandari F, Christie IC, Torvik S, Silverman MN, Phillips TM, Sternberg EM Elevated neuroimmune biomarkers in sweat patches and plasma of premenopausal women with major depressive disorder in remission: the POWER study. Biol Psychiatry 64:907-911.2008. Goshen I, Kreisel T, Ben-Menachem-Zidon O, Licht T, Weidenfeld J, Ben-Hur T, Yirmiya R Brain interleukin-1 mediates chronic stress-induced depression in mice via adrenocortical activation and hippocampal neurogenesis suppression. Mol Psychiatry 13:717-728.2008. Miller AH Mechanisms of cytokine-induced behavioral changes: Psychoneuroimmunology at the translational interface. Brain Behav Immun 23:149-158.2009.
POSTER #41 EFFECT OF QUINPIROLE ON PRODUCTION OF 50 kHz ULTRASONIC CALLS IN WISTAR RATS. Melanie D. Komadoski, MSc. Student in Neurobiology, Stefan M. Brudzynski, PhD, DSc. Department of Psychology, Brock University, St. Catharines, ON, L2S 3A1 Canada. Rats communicate with two main types of ultrasonic vocalizations labelled as 22 kHz alarm calls and 50 kHz social calls. While the 22 kHz vocalizations are initiated by the activity of the ascending cholinergic system, the 50 kHz social calls are initiated by activity of the mesolimbic dopamine system. Intracerebral application of dopamine agonists (e.g., amphetamine) have been reported to produce increased numbers of 50 kHz calls. The 50 kHz calls are subdivided into sub-categories depending on the their sonographic structure, into frequency-modulated (FM) and non-modulated calls. It is not exactly known what type(s) of calls are emitted under the conditions of pharmacological stimulation. The goal of the present experiment was to induce 50 kHz calls by a direct intraaccumbens application of low to medium doses of dopamine agonist, quinpirole, and a subsequent analysis of induced call types. Intracerebral injection of quinpirole in a dose range of 0.12 - 1.00 Âľg increased production of 50 kHz calls as compared to results after injection of isotonic saline (Kruskal-Wallis ANOVA, P # 0.02). The total number of 50 kHz calls increased two- to three-fold after application of 0.12-0.25 Âľg but to a lesser degree after higher doses. The fraction of different types of calls after quinpirole was changed. An eight-fold increase in trill calls (Fisher exact test, p < 0.03) and two-fold increase in flat calls (p <0.05) were observed, while step calls and other types of modulated calls were not significantly changed. We may conclude that the low dose of quinpirole predominantly increased FM calls with trills and, to a smaller degree, flat calls but not other types of 50 kHz calls. The other type of calls included FM-step calls and other sonographic forms of FM changes. Supported by NSERC of Canada.
POSTER #42 REGULATION OF GDNF mRNA IN RAT MYOTUBES Anna Korol1, James R. Bain, MD2, Margaret Fahnestock, PhD2 1
Undergraduate Student, Biology and Psychology, 2Department of Medicine, Division of Surgery, and 3Department of Psychiatry and Behavioural Neurosciences, McMaster University Glial cell line-derived neurotrophic factor (GDNF) was first identified as a potent survival factor for midbrain dopaminergic neurons. Since its discovery, it has been shown to have neurotrophic effects on several neuronal populations, including motoneurons. GDNF is synthesized in the muscle and is retrogradely transported to the neuron, where it promotes growth, differentiation and survival. Following peripheral nerve injury GDNF mRNA and protein levels are upregulated in both the muscle and nerve, where it plays a role in enhancing regeneration. In previous studies using differentiated L6 myoblast cells in culture as an in vitro model for denervated muscle, our lab has shown that exogenous application of either homogenized rat sciatic nerve or the sensory neurotransmitter calcitonin gene-related peptide (CGRP) increases GDNF protein in the culture medium. This suggests that CGRP may act as a nerve injury signal responsible for GDNF regulation. In this study, we investigated the mechanism of CGRPinduced GDNF upregulation. Myotubes were treated with either homogenized rat sciatic nerve or CGRP, and levels of GDNF mRNA expression were measured using quantitative real-time RT-PCR. The results showed that there was no significant upregulation of GDNF mRNA in either the samples treated with nerve homogenate or CGRP. This demonstrates that the increased GDNF protein in the culture medium following treatment does not occur at the transcriptional level. Therefore, although CGRP may increase translation or secretion of GDNF, it is not responsible for transcriptional regulation of GDNF in muscle following nerve injury.
POSTER #43 EFFECTS OF TENEURIN C-TERMINAL ASSOCIATED PEPTIDE-1 (TCAP-1) ON STRESSINDUCED REINSTATEMENT OF COCAINE SEEKING Kupferschmidt DA1, Barsyte D, Rotzinger S123, Lovejoy DA3, Erb S1. Department of 1Psychology, 2Psychiatry, and 3Cell & Systems Biology, University of Toronto Studies using an animal model of relapse known as the reinstatement procedure indicate that stressors, such as footshock (FS), serve as powerful triggers of drug seeking in rats. The stress-related neuropeptide system corticotropin-releasing factor (CRF) has been shown to mediate the effects of stress on the reinstatement of drug seeking. Specifically, CRF receptor antagonists are known to block FS-induced reinstatement, whereas central injections of CRF induce the reinstatement of drug seeking [Erb & Stewart (1999) J Neurosci 19:RC35; Shaham et al (1998) Psychopharm 137:184-90]. The recently discovered teneurin C-terminal associated peptides (TCAP) have been shown to modulate the CRF stress response. For example, repeated (5-day) pretreatment with a synthetic variant of TCAP-1 inhibits CRF-induced behavioural responses in various animal models of anxiety and depression [Al Chawaf et al (2007) Peptides 28:1406-15]. Neuroanatomical studies indicate that TCAP-1 is expressed in brain regions implicated in stress-induced reinstatement [Wang et al (2005) Mol Brain Res 133:253-65; Shaham et al (2000) Brain Res Brain Res Rev 13-33] that are known to contain high densities of CRF cell bodies and terminals [Sawchenko et al (1985) Fed Proc 44:221-7]. Moreover, acute pretreatment with TCAP-1 prior to a CRF challenge attenuates CRF-induced neuronal activation within these same brain regions [Tan et al: in prep]. Given the known modulatory effects of TCAP on the CRF stress response, and the neuroanatomical convergence between TCAP and CRF systems, the present series of experiments were designed to determine whether pretreatment with TCAP-1 modulates stressinduced reinstatement of cocaine seeking. Rats were first trained to self-administer cocaine for 8-10 days. Rats subsequently received acute and/or repeated TCAP-1 (0, 300 pmol, i.c.v.) prior to tests for CRF- (0, 0.5 ug, i.c.v.) and FS- (0, 0.9 mA) induced reinstatement of cocaine seeking. Repeated TCAP-1 pretreatment prior to testing for reinstatement significantly attenuated the effects of CRF, but not FS, on the reinstatement of cocaine seeking. The present findings extend our understanding of the behavioural manifestations of central TCAPCRF interactions and provide further insight into the regulatory mechanisms of the mammalian stress response.
POSTER #44 The effects of thyroid hormone on neurotrophin expression during seasonal transitions in the ewe Zamin Ladha, M.Sc. Student, Graduate Studies in Anatomy & Cell Biology; Lique M Coolen, PhD, University of Western Ontario; Robert L Goodman, PhD, West Virginia University; Michael N Lehman, PhD, University of Western Ontario Many animals exhibit an annual cycle of fertility that synchronizes the timing of reproductive activity and the birth of offspring. In the sheep, the transition from the breeding season to anestrous is associated with morphological and molecular changes in the gonadotropin-releasing hormone neurosecretory system to. This transition to anestrous is known to be dependent on the thyroid hormone, thyroxine (T4), as removal of the thyroid gland (THX) during the late breeding season prevents the onset of anestrus. T4 can act in multiple sites to regulate this seasonal transition, including the ventral medial preoptic area (vPOA) and premammillary region (PMR) of the hypothalamus, where T4 microimplants prevent the effects of THX. Moreover, the anatomy of dopamine neurons in the A15 region of the hypothalamus, which are involved in seasonal changes in estrogen negative feedback, is influenced by T4. Glutamatergic and synapsin-positive inputs onto A15 dopamine neurons are increased in anestrous, an effect correlated with longer dendrites of these A15 neurons. This latter observation is dependent on T4. Since neurotrophins and their receptors play an important role in mediating T4-dependent neuroplasticity during development, we examined neurotrophins as mediators of T4â€™s influence during the transition to anestrous. In this study, we used Real TimePCR to determine whether the presence of T4, in thyroid-intact ewes, influences the expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in hypothalamic regions during the transition to anestrous. Results indicate that thyroid-intact ewes have decreased BDNF mRNA expression in the A15 but increased expression in the MBH compared to THX ewes. In contrast, NGF mRNA expression is increased in the A15 and decreased in the vPOA of thyroid-intact ewes. Thus both neurotrophins may be involved in mediating the T4 dependent changes by acting in different regions of the hypothalamus. In a second experiment, immunohistological staining for the receptor for BDNF, tyrosine kinase B (TrkB), was conducted in late breeding season thyroid-intact and THX animals. Preliminary analysis suggests that thyroid-intact animals may have decreased TrkB fiber density staining in the A15 compared to THX animals. The functional importance of these changes in expression of BDNF and NGF and their receptors is currently unknown; however, it is clear that these factors are regulated by T4 and correlated with synaptic and morphological changes in the A15. Our findings provide initial evidence pointing to alterations in expression of these neurotrophins as possible mediators of the actions of T4 necessary for alterations in the neural circuitry mediating seasonal reproduction in the sheep. Supported by NIH R01 HD017864 to R.L.G. and M.N.L.
POSTER #45 Is there a cytoprotective role for DJ-1 in a mouse model of ataxia-telangiectasia? Keith Ho B.Sc., Jennifer K. Griffin Ph.D., Howard T.J. Mount Ph.D. Centre for Research in Neurodegenerative Diseases, Dept. Medicine (Div. Neurology) University of Toronto, CANADA PARK7/DJ-1 is a multifunctional protein that has been implicated in both cancer and neurodegeneration. DJ-1 is upregulated in small cell carcinoma of the lung and is positively associated with relapse of disease. Loss-of-function mutations in DJ-1 cause an early-onset recessive form of Parkinsonâ€™s disease (PD). Ataxia telangiectasia (AT), a neurodegenerative disease caused by mutations in the ATM protein, is characterised by progressive ataxia, cerebellar Purkinje cell loss, susceptibility to soft tissue tumours and radiosensitivity. ATM senses double-strand breaks in DNA and, when activated, phosphorylates numerous targets including p53. In Atm-deficient (Atm-KO) cells, the activation and stabilization of p53 is defective, leading to a short-term abrogation of the cytotoxicity induced by DNA damage. The high levels of DJ-1 in p53 mutant cancer cells may contribute to their proliferative capacity, through stimulatory effects of DJ-1 on the PI-3 kinase signaling pathway. As p53- and ATMdeficiencies represent phenocopy disorders, we examined what role DJ-1 might play in the AtmKO mouse model of A-T, that develops cancer, but not Purkinje cell degeneration. We found DJ-1 expression in the Atm-KO and wild type (WT) brain to be similar. However, under conditions of genotoxic stress (8 Gy ionizing radiation) we observed increased DJ-1 immunoreactivity in Atm-KO, but not WT Purkinje cells. To assess whether DJ-1 might be protective, we compared effects of doxorubicin-induced genotoxic stress on WT and DJ-1-KO embryonic fibroblasts in the presence, or absence of the ATM inhibitor, KU55933. Doxorubicintreated DJ-1-KO fibroblasts exhibited a dramatic increase in cell death under conditions of Atm inhibition. This enhanced toxicity was attenuated by coincubation with the p53 inhibitor, $pifithrin. In WT cells treated with doxorubicin and KU55933, we observed a correlation between DJ-1 levels and doxorubicin-resistance. Together, these observations suggest that DJ-1 upregulation protects Atm-KO cells from genotoxic stress. To examine the interaction between Atm and DJ-1 in vivo, we crossed DJ-1-KO and Atm-deficient mice. Doubly-deficient (DJ1/Atm-KO) mice exhibited perinatal viability comparable to that of Atm-KO mice. Like their AtmKO counterparts, the DJ-1/Atm-KO mice eventually succumbed to tumours. However, DJ1/Atm-KO mice died later (39 +/- 2.9 weeks N=34) than did Atm-KO animals (23 +/- 2.3 weeks N=20). Thus, the absence of DJ-1 delays onset of tumours, but does not prevent their occurrence. In conclusion, DJ-1-deficiency may confer enhanced acute vulnerability to genotoxic stress in AT cells. The effects of DJ-1-deficiency on genotoxicity and delayed tumorigenesis suggest potential benefits and risks of targeting this nodal protein in the management of AT cancers. Supported by CIHR.
POSTER #46 Behavioural phenotypes of DJ-1-deficient mice implicate altered transmission in multiple brain areas and are differentially affected by Atm expression. Emily Lam, B.Sc. Student, Undergraduate Studies in Physiology; Keith Ho, M.Sc. Student, Graduate Studies in Physiology; Jennifer Griffin, PhD, Centre for Research in Neurodegenerative Diseases; Jennifer Mac, Co-op student, Humberside Collegiate Institute, Mary Brown, Centre for Research in Neurodegenerative Diseases; JoAnne McLaurin, PhD, University of Toronto; Howard T. J. Mount, PhD, University of Toronto. Mutations in the DJ-1 gene result in a loss of functional DJ-1 protein and cause early-onset familial Parkinsonâ€™s disease. DJ-1-knockout (DJ-1-KO) mice exhibit hypersensitivity to MPTP, a dopaminergic neurotoxin, as well as progressive disruption of gait and impaired corticostriatal and hippocampal synaptic activity. Thus, it appears that DJ-1 is involved in the function of brain regions beyond the dopaminergic nigrostriatal neurons that are targeted in Parkinsonâ€™s disease. Increases in DJ-1 expression are associated with certain cancers and have been observed in p53 mutant tumour lines. Ataxia telangiectasia (AT) is a neurodegenerative disorder caused by loss of functional ATM, the kinase that phosphorylates p53 in response to genotoxic stress. In human patients, AT is characterized by an increased risk of cancer as well as Purkinje and granule cell death in the cerebellum. In an Atm-KO mouse model of AT, we discovered increased expression of DJ-1 in Purkinje neurons following exposure to genotoxic stress. Intriguingly, these neurons do not degenerate, suggesting a possible neuroprotective role for DJ-1 expression in the ATM/p53-dependent genotoxic stress response. Collectively, these findings led us to test whether and how deficiencies in the two proteins might regulate murine behavioural phenotypes. In this study, we subjected DJ-1-KO mice on wild type and Atm-KO backgrounds to tests of cognition, neuromotor function and affect. DJ-1-KO mice were impaired in cortically-encoded novel object recognition memory and in a Morris water maze test of hippocampal spatial memory. These findings were not surprising to us, in view of the welldocumented effects of DJ-1 deficiency on electrophysiological parameters in hippocampus and corticostriatal transmission. In a test of forelimb incoordination that has been shown to be sensitive to disrupted nigrostriatal dopamine, and in a test of gait symmetry, DJ-1-KO mice exhibited progressive impairment. Similarly, in a test of behavioural despair, DJ-1-KO mice exhibited increased immobility, a measure that is inversely correlated with synaptic noradrenaline turnover. Exploration of open quadrants in the zero-maze, a measure of anxiety that is sensitive to serotonin transmission, was reduced in DJ-1-deficient mice. Combined deficiencies in Atm and DJ-1 abrogated the forelimb impairment, gait asymmetry and behavioural despair of DJ-1-KO mice. Conversely, DJ-1-KO anxiety in the zero maze was exacerbated by Atm-deficiency. We suggest that reciprocal putative effects of DJ-1 and Atm deficiencies on expression of the transporters for dopamine and noradrenaline, but not serotonin, could underlie the phenotype-cancelling effect of combined deficiencies in these proteins. Supported by CIHR and the Parkinson Disease Foundation (NY, NY).
POSTER #47 OPIATE-INDUCED LOCOMOTION DEFICITS IN M5 MUSCARINIC RECEPTOR KNOCKOUT MICE ARE REVERSED AFTER FOOD DEPRIVATION Lee, Esther1, Steidl, Stephan2, Wasserman, David2 and Yeomans, John S.1,2,3 1 Department of Cell & Systems Biology, University of Toronto, Toronto, ON 2 Department of Psychology, University of Toronto, Toronto, ON 3 Centre for Biological Timing and Cognition (CBTC), University of Toronto, Toronto, ON The rewarding effects of opiates are mediated through both mesolimbic DA neurons, and DAindependent pathways such as the pedunculopontine tegmental nucleus (PPT). Morphine induces DA release in the nucleus accumbens (NAc) of mice, but not in knockout (KO) mice lacking M5 muscarinic receptors associated with ventral tegmental nucleus (VTA) DA neurons. In contrast, M5 muscarinic receptor KO mice show reduced locomotion in response to systemic morphine, indicating that morphine-induced locomotion is mediated in part through M5 muscarinic receptors in the VTA. Although morphine reward is acutely mediated through PPT DA-independent pathways, morphine reward becomes dependent on VTA DA neurons in food-deprived rats, suggesting a switch in opiate reward pathways from PPT to DA neurons. Here, we examined how 18 hours food deprivation affects the locomotor stimulant properties of a single dose of morphine (10 mg/kg, i.p.) in wild-type (WT) and M5 muscarinic receptor KO mice of the C57BL/6 strain. Namely, can morphine-induced locomotor deficits in M5 KO mice be reversed after food deprivation? As we found previously, non-deprived WT mice showed greater morphine-induced locomotion relative to M5 KO mice. In food-deprived mice exposed to morphine, WTs showed reduced locomotion relative to non-deprived WT mice. In contrast, morphine-induced locomotion increased after food deprivation in M5 KO mice relative to non-deprived KO mice. Most importantly, in food-deprived mice, KOs showed greater morphine-induced locomotion compared to WTs. These results suggest that food deprivation switches the morphine effect from a M5-dependent DA pathway to an M5-independent DA pathway.
POSTER #48 OREO COOKIES = COCAINE? Levy, AnneMarie BA & Leri, Francesco, PhD Department of Psychology, University of Guelph, 50 Stone Road East, Ontario, N1G 2W1. Objective: Co-morbidity between substance use, eating disorders and depression is prevalent, yet poorly understood. Three experiments were conducted to explore whether preference for a highly palatable food was related to intravenous (IV) cocaine self-administration (SA), locomotor reactivity to cocaine and whether palatable food could reinstate cocaine-seeking in rats. Methods: In experiment 1, non-food deprived, male Sprague-Dawley rats were used to assess whether Oreo cookies could induce a conditioned place preference (CPP). To this end, rats (N=72) received eight conditioning sessions (one 30 min session per day) during which they had access to either a single Oreo (12g) in one compartment or no food in the other. Eleven days following the CPP test, the same rats were given the opportunity to self-administer cocaine or had locomotor reactivity assessed in response to cocaine. In experiment 2, rats (n=48) selfadministered cocaine (0.25 mg/kg/infusion, IV) on a continuous schedule of reinforcement for one 3h session/day for 8 days. Following acquisition, rats underwent extinction training, one 3h session/day for 11 days and then reinstatement of cocaine-seeking precipitated first, by the consumption of Oreos and secondly, by cocaine prime (20 mg/kg, IP) just prior to testing. In experiment 3, rats (n=24) were injected with cocaine (0, 3, 15, and 30 mg/kg, IP) and confined to activity chambers for one 2h locomotion test/day for 4 days. A balanced latin square design was used to control for the order of injections. Results: Rats displayed either a significant preference, or aversion for the Oreo-paired compartment, that was not related to the quantity of Oreos consumed in the conditioning phase of CPP. During self-administration, preference rats displayed greater responding during acquisition and extinction training compared to aversion rats. At test, consumption of Oreos precipitated cocaine-seeking in preference but not aversion rats, and the cocaine prime was effective in both groups; however, the magnitude of reinstatement was greater in the preference rats. Finally, there was a cocaine dose dependent increase in locomotion in both groups; however, locomotion was significantly lower in the preference rats in response to the 15 mg/kg cocaine. Conclusion: Individual differences in the development of a preference or aversion for the Oreopaired compartment were reflected in both the SA profile and locomotor reactivity to cocaine in rats. Preference rats maintained higher responding during acquisition, and displayed less locomotor reactivity to cocaine compared to avoidance rats, suggesting that variability in the motivational properties of highly palatable foods may be related to differences in sensitivity to the reinforcing effects of drugs of abuse. However, this will require further testing with a wider range of cocaine doses on a progressive ratio schedule of reinforcement in SA. .
POSTER #49 Social Deprivation of Infant Rats Differentially Alters Responding to a Conditioned Cue Depending on its Predictive Value A. M. Lomanowska & G. W. Kraemer Department of Psychology, University of Toronto at Mississauga, Mississauga, ON OBJECTIVES: Social adversity in early life, such as child abuse or neglect, is a risk factor for increased vulnerability to drug addiction. A prominent feature of this disorder is intense craving for the drug in the presence of cues associated with drug reward. The present study used an animal model to investigate whether early rearing in a socially deprived environment alters the responding to reward-associated cues. METHODS: Rats were reared either by the mother (maternally reared; MR, n=18) or in complete isolation from the mother and litter using the â€œpup-in-a-cupâ€? method (artificially reared; AR, n=16) until weaning. In adulthood, rats were trained on one of three Pavlovian conditioning schedules that varied according to the predictive relationship between an auditory cue (white noise) and a food reward. In the Contingent condition, food reward was delivered into a recessed magazine only during the presentation of the cue. In the Non-Contingent condition, food reward was only delivered in the inter-trial interval between cue presentations. In the Semi-Contingent condition, food reward was delivered during the presentation of a cue as well as during the inter-trial interval. All rats were subsequently trained to press a lever to obtain a food reward. Responding to the conditioned cue was measured during an extinction session when rats had access to the lever and food magazine, but no rewards were delivered. RESULTS: There were no differences between AR and MR rats in the acquisition phase of Pavlovian or instrumental training. There were also no differences in lever presses or magazine entries in response to cue presentations during extinction between AR and MR rats trained in the Contingent and Non-Contingent conditions. However, AR rats trained in the SemiContingent condition showed more magazine entries than MR rats during the entire extinction session. CONCLUSION: The results indicate that early rearing in a socially deprived environment differently affects responding to a conditioned cue depending on the predictive relationship between the cue and the reward. Socially deprived rats show increased responding to an associative cue in circumstances when the contingency between the cue and the reward is partial. The findings of this study suggest that adverse early social experience affects encoding of the predictive value of associative cues in later life.
POSTER #50 Social Isolation of Infant Rats Followed by Resocialization in a Complex Environment Results in Perseverative Reversal Learning Deficits S. J. Mooney, A. M. Lomanowska & G. W. Kraemer Department of Psychology, University of Toronto at Mississauga, Mississauga, ON OBJECTIVES: Reversal learning tasks demonstrate an animalâ€™s ability to flexibly switch between reward contingencies. Recent research indicates that infant rats reared in social isolation have deficits in this type of cognitive flexibility. This study examined whether reversal learning deficits produced by isolation rearing were perseverative in nature or whether they were due to learned non-reward. The effects of resocialization in a complex environment on cognitive flexibility were also examined. METHODS: Rats were reared either by the mother (maternally reared; MR, n=21) or in complete isolation from the mother and litter using the â€œpup-in-a-cupâ€? method (artificially reared; AR, n=24) until weaning. Half of the rats in each condition were then housed in complex environments with four rats per cage and the remaining animals were housed in standard cages with two rats per cage. In adulthood, rats were trained for 12 days to discriminate between two auditory stimuli. One resulted in a food reward and the other was unrewarded. Rats were then subjected to one of two reversal conditions. To test for perseveration, half the rats were given their previously rewarded stimulus as an unrewarded stimulus. The previously unrewarded stimulus was replaced by a novel stimulus which became the rewarded stimulus. To test for learning deficits related to learned non-reward, the remaining animals were given their previously unrewarded stimulus as a rewarded stimulus. The previously rewarded stimulus was replaced by a novel stimulus which became the unrewarded stimulus. RESULTS: There were no differences resulting from different rearing and housing conditions in the initial Pavlovian training or in the test for learned non-reward. AR rats housed in complex cages demonstrated more perseveration than MR rats housed in complex cages, but there were no differences due to rearing in rats housed in standard cages. CONCLUSION: These results demonstrate that rearing rats in a socially deprived environment differentially affects responding to conditioned cues depending on their later housing experience. Socially deprived rats show more perseverative responding to a previously rewarded cue after the cue-reward contingency is eliminated. These results suggest that resocialization exaggerates learning deficits resulting from social isolation in early life.
POSTER #51 Decreased Processing of ProBDNF to BDNF in Visual Cortex of Dark-Reared Mice Juan Pablo Lopez$, Bernadeta Michalski.$, Douglas O. Frost Ph.D.%,& Margaret Fahnestock Ph.D.$ $Department of Psychiatry and Behavioural Neurosciences, McMaster University, %Department of Pharmacology and Experimental Therapeutics and &Department of Anesthesiology and Neuroscience Program, University of Maryland School of Medicine Brain-derived neurotrophic factor (BDNF) is secreted in response to neuronal activity and has been proposed as a mediator of activity-dependent neural plasticity. Visual experience regulates the growth, stabilization, and elimination of immature connections of cortical neurons. Previous studies in the visual system have shown that rearing in constant light or darkness alters the levels of BDNF protein and mRNA in the mammalian brain. Until recently, only mature BDNF (mBDNF) had been considered biologically active, but recent studies have shown that precursor BDNF (proBDNF) facilitates long term depression (LTD) and can be cleaved extracellularly to mBDNF. The ratio of these two molecules is very important given their opposing biological effects. In this study we explore whether or not light stimulation induces cleavage of proBDNF to mBDNF. Mice were reared in one of three conditions: (1) Normally Reared (NR); (2) Dark Reared (DR); (3) Dark Reared exposed to two hours of light prior to sacrifice (DR+2). Tissues were collected from the primary visual cortex, superior colliculus, cerebellum, and hippocampus and were subjected to western blot and quantitative analysis. Both forms of BDNF were detected in mouse brain homogenates, although proBDNF was the predominant form, representing roughly 97% of total measured BDNF in primary visual cortex. Our preliminary results indicate that cleavage of proBDNF to mBDNF is significantly decreased in visual cortex of dark reared mice compared to normally reared animals, and that only 2 hours of light exposure is required to induce processing. Analysis of the remaining tissues is in process.
THE EFFECTS OF A NOVEL DRUG COMBINATION AND VOLUNTARY EXERCISE IN A SURVIVAL STUDY USING AN ALS MOUSE MODEL Rosamond E. Lougheed (M.Sc. Candidate, MiNDS Graduate Program) and John Turnbull (Professor and Head of Neurology, Department of Medicine, McMaster University) Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that affects both upper and lower motor neurons, resulting in progressive paralysis and invariably, death. Despite its global status as the most prevalent human motor neuron disease and an extraordinary number of clinical trials in recent years, there are presently no reliable treatments that extend beyond the palliative realm. Mutations in the human Cu/Zn superoxide dismutase 1 (hSOD1) gene are causal in about 2% of all ALS cases. The induction of motor neuron death by mutant forms of the SOD1 enzyme (mhSOD1) is thought to be complex and the result of abnormalities along multiple cellular pathways. For this reason, numerous recent studies have sought to delay symptom onset by administering a cocktail of drugs. We are conducting a large-scale survival study using the standard transgenic ALS mouse model (mhSOD1 with a glycine to alanine mutation at amino acid 93) to determine the effects of a novel drug combination of lithium and rapamycin. Studies using lithium, which upregulates autophagy (and the clearance of mhSOD1) by inhibiting inositol mono-phosphatase 1, reported a significant delay in symptom onset and increased survival in the mhSOD1 mouse. Rapamycin also enhances autophagy by inhibiting the mammalian target of rapamycin. Rapamycin has been used in various studies of neurodegeneration, but has not been tested in the ALS mouse model to date. This drug combination serves to increase autophagy across two independent pathways, therefore we predict that the pharmacological effects will be synergistic in combination. We are treating both sedentary mice and mice in cages equipped with a running wheel. Exercise may have an independent and synergistic effect with the other treatments, possibly through an induction of heat shock proteins. It is our intent to use the data from this research to assist in the development of future clinical trials.
POSTER #53 Acute effects of cadmium on octavolateralis structure and function in the fathead (Pimephales promelas) and bluntnose minnows (Pimephales notatus) Jennifer Low, M.Sc. Candidate, Department of Biological Sciences, University of Windsor; Dennis M. Higgs, PhD, Department of Biological Sciences, University of Windsor The accumulation of pollutants in local waters is becoming an increasing issue as the Detroit River has been officially listed as an â€œArea of Concernâ€?. According to the Remedial Action Plan for the Detroit River, cadmium is one of the main chemicals of concern. Previous work has shown cadmium to be a potent toxin for external sensory structures of some fish species, but potential effects on internal structures and on local species remains to be determined. The current study examines the acute effects of cadmium on the structure and function of the octavolateralis system in the fathead (Pimephales promelas) and bluntnose (Pimephales notatus) minnows - two local species that are common models for ecotoxicology. In the laboratory, fathead minnows were exposed for 96 hours in a range of cadmium concentrations (0.5-5'g/L) that represent concentrations seen in natural systems. After exposure, fish were tested for hearing ability using the auditory brainstem response and compared to unexposed controls. Hair cell numbers were quantified, in both the inner ear (internal sensory structure) and neuromasts (external sensory structure), to examine potential structural deficits caused by cadmium exposure. In the field, bluntnose minnows will be collected from clean and contaminated sites to determine if effects seen with defined exposures in the lab are replicated in a natural setting. Preliminary results to date show that fish exposed to high concentrations of cadmium exhibit a decrease in hearing sensitivity and thus an increase in hearing threshold (the minimum sound level that can be detected) compared to controls. Studies examining the effects of a range of cadmium levels are currently being run. More specifically, changes in hearing threshold and response latency (the time it takes for the brain to respond to sound) are being examined. Hair cell quantification to date has shown no significant difference between fish exposed to high concentrations of cadmium and control fish. These preliminary results indicate that cadmium may have a functional effect on hearing, but not a structural effect. By combining ecotoxicology with histological and neurophysiological approaches, as well as with a field approach, we will be able to link the structural and functional deficits that may be caused by cadmium exposure and be better able to assess the potential effects of this common pollutant on sensory abilities vital to fish survival. From an ecological perspective, if cadmium does in fact have an effect on the octavolateralis system in fish, it will in turn greatly affect many important fish behaviours. Both lab and field components will contribute to the extrapolation of the results of this study back to the Great Lakes ecosystem as it is important for the overall health of the lakes. There is also the potential to use these results to more accurately assess habitat quality for prioritization of remediation efforts.
POSTER #54 NOVELTY DETECTION NEURONS IN THE RAT'S DORSAL CORTEX OF THE INFERIOR COLLICULUS Ariana Lumani, M.Sc. Student, Sara Dawood, Undergraduate Student, and Huiming Zhang, Ph. D., Department of Biological Sciences, University of Windsor. The dorsal cortex of the inferior colliculus (ICd) is one of the major subdivisions of the auditory midbrain. This structure receives numerous descending projections from the auditory cortex, but does not receive direct ascending inputs from brainstem structures. This innervation pattern suggests that the ICd plays a special role in auditory processing. Using the rat as an animal model, we recorded responses to sounds from single neurons in the ICd in order to determine the specific roles of this structure in hearing. We examined temporal characteristics of responses to 100 ms tone bursts presented to the ear contralateral to the recording site. Our results revealed that many neurons in the ICd had temporal firing patterns that were not frequently encountered in lower brainstem structures. For example, a substantial number of ICd neurons displayed “offset” or “on-off” firing patterns. The latencies of many ICd neurons were longer than those of neurons in the central nucleus of the inferior colliculus as well as in lower brainstem structures. For ICd neurons with continuous firing during a tone burst, a large variation existed in the latency of the first spike under repetitive sound stimulations. The most distinct characteristic displayed by many ICd neurons was habituation. These neurons displayed strong responses to initial presentations of repetitive sounds, but erratic or minimal spiking thereafter. The responses of neurons with habituation could be restored by changes in sound intensity or frequency. Neurons showing habituation were further studied using multiple sounds with different qualities presented at randomized sequences. Our results indicated that randomization of acoustic stimuli reduced the degree of habituation in ICd neurons. Our physiological data suggest that many neurons in the ICd selectively respond to novel sounds. This response characteristic might be used by the auditory system in directing auditory attention to novel sounds. Research supported by NSERC of Canada and the University of Windsor.
POSTER #55 Analysis of A" and Neuroinflammation as a Function of Brain Region and Disease Progression in the TgCRND8 Brain Keran Ma, M.Sc. student, Graduate Studies in Physiology; JoAnne McLaurin, PhD, Laboratory Medicine and Pathobiology, Centre for Research in Neurodegenerative Diseases, University of Toronto; Howard T.J. Mount, PhD, Physiology, Centre for Research in Neurodegenerative Diseases, University of Toronto An association has been observed between beta-amyloid (A") deposition and neuroinflammation in the brains of both Alzheimerâ€™s disease (AD) patients and transgenic mouse models. Increasing levels of A" are correlated with higher expressions of proinflammatory cytokines and these cytokines in turn modulate A" expression. The transgenic mouse model of AD, TgCRND8, which encodes the Indiana and Swedish APP mutations, has been used as a model to study AD for the past 8 years. However, A"42 and A"40 levels in various regions of the brain as well as levels and distribution of pro-inflammatory cytokines at different stages of disease progression have not been characterized. We hypothesized that A" levels in TgCRND8 mice increase as a function of disease progression and are higher in AD severely affected brain regions, and levels of pro-inflammatory cytokines would correlate with regional A" levels. In 4, 6, and 8 month old TgCRND8 mice, A"42 and A"40 ELISAs were used to measure levels of formic acid extracted insoluble and diethylamine extracted soluble A" in selected brain regions. Using cytokine multi-plex assays, regional levels of pro-inflammatory cytokines at each disease stage were measured and the cellular localization of interleukin-1" was observed by immunofluorescence staining. Both A"40 and A"42 levels are higher in the hippocampus, olfactory bulbs, and the cortex compared to the cerebellum, septum and striatum. A"42/A"40 ratio decreases as disease progresses due to recruitment of A"40 into plaques. A"40 insoluble/soluble ratio increases over time whereas the A"42 insoluble/soluble ratio decreases. A survey of the expression of pro-inflammatory cytokines, TNF-!, IL-1", IFN-(, IL-6, IL-12p70, and chemokine CXCL1 in the same brain regions indicate that IL-1" could be a promising cytokine that correlates with A" levels. Immunofluorescence staining showed increased expression of IL-1" in the hippocampus, olfactory bulbs, and the cortex, regions with high A" levels.
POSTER #56 ALTERED NMDAR EXPRESSION AND LOCALIZATION IN AN ANIMAL MODEL OF RETT SYNDROME â€“ POSSIBLE ROLE IN RETT SYNDROME PATHOPHYSIOLOGY? Ewelina Maliszewska-Cyna, MSc. Student, Toronto Western Research Institute, University of Toronto; Damanpreet Bawa, MSc., University of Toronto; James Eubanks, PhD, Toronto Western Research Institute, University of Toronto. Rett Syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked gene encoding the MeCP2 protein. Rett patients develop normally for the first year of life, but then lose acquired skills. Despite knowing the causative gene, relatively little is known about how the loss of MeCP2 affects neurophysiology leading to RTT. Immature neurons are one hallmark of the Syndrome, suggesting that factors involved in neuronal maturation are being affected. One system required for normal neuronal maturation is the glutamate receptors system. For example, the NR2A subunit of NMDA-responsive glutamate receptor plays a key role in normal synaptic maturation - neurons lacking NR2A subunit from the receptor are phenotypically and functionally immature. Consistently, our data show that NR2A is underrepresented in the hippocampus of MeCP2-deficient mice, suggesting that some of the neurophysiological deficits of these mice may arise from misregulated NR2A signaling. In my project I am testing the hypothesis that NMDA prevalence and distribution is altered throughout the brain of symptomatic MeCP2-deficient mice. My results show that while NR2A expression is diminished throughout the brain, the protein that is present distributes within neurons similarly to wild type. My results also show that a similar decrease in prevalence with preservation of distribution is seen for NMDAR subunits NR1 and NR2B, and for Postsynaptic Density Protein 95 (PSD-95). Collectively, these results suggest that although the number of synapses in MeCP2-deficient brain is decreased, the synapses that are present form properly, and contain a normal representation of post-synaptic density components. These results challenge the current models of RTT pathophysiology by suggesting that the Syndrome relates to diminished numbers of synapses rather than to a normal number of immature synapses. In conclusion, these data support the role for altered NMDA receptor activity in RTT, but indicate that the pervading models of Rett Syndrome ontogenesis require re-evaluation.
POSTER #57 A Role of CYP2D6 in Protection Against MPP+ Neurotoxicity in SH-SY5Y Human Neuroblastoma Cells Mann, Amandeep, M.Sc. and Tyndale, F. Rachel, Ph.D. Centre for Addiction and Mental Health and University of Toronto. Cytochrome P450 (CYP) 2D6 is an enzyme, which is expressed in liver and at lower levels in number of extrahepatic tissues including the brain. CYP2D6 inactivates neurotoxins such as 1methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 1,2,3,4-tetrahydroisoquinoline (TIQ) and some pesticides. Genetically slow metabolizers of CYP2D6 are at higher risk for developing Parkinsonâ€™s Disease (PD), a risk that increases with exposure to pesticides. Conversely, smokers display a reduced risk for developing PD and have higher levels of brain CYP2D6. In monkey and rat, nicotine induces brain CYP2D, and nicotine is neuroprotective in in vivo/in vitro models of PD. One possible mechanism of neuroprotection may be through induction of CYP2D6 in the brain by nicotine. In support of this, over-expression of CYP2D6 in PC12 cells reduces toxicity against MPP+ and male Dark Agouti rats, which are deficient in CYP2D activity, show increased susceptibility to the effects of MPTP. The goal of this study is to elucidate the role of CYP2D6 in an in vitro neurotoxicity model. Hypothesis: Inhibiting CYP2D6 will increase MPP+ neurotoxicity. Method: SH-SY5Y human neuroblastoma cells were assessed for CYP2D6 expression using western blotting and immunocytochemistry, and activity by 3-[2-(N, N-diethyl-N-methylammonium)ethyl]-7-methoxy-4-methylcoumarin (AMMC) metabolism. Cells were treated with the neurotoxin MPP+ in the presence/absence of CYP2D6 inhibitors (quinidine, propanolol, metoprolol or timolol) at varying concentrations and measured for cell viability. Results: CYP2D6 was expressed in SH-SY5Y cells. Nicotine at 1 M significantly (p<0.05) induced CYP2D6 by 1.7-fold. Quinidne at 1 M inhibited ~80-90% of AMMC metabolism. Co-treatment with MPP+ and CYP2D6 inhibitors increased cell death: quinidine (0.01-10 M) increased cell death by 10-20% (p<0.01), propanolol (1 M) increased cell death by ~20% (p<0.05), metoprolol (1 &10 M) increased cell death by ~12-18% (p<0.05), and timolol (1 M) increased cell death by ~13-18% (p<0.05). Conclusion: These results suggest that CYP2D6 is playing a small but significant role in protecting these cells from MPP+ neurotoxicity. To investigate whether higher levels of brain CYP2D6 play a role in protecting smokers from PD, this in vitro model will be used to test the influence of nicotine induced CYP2D6 on MPP+ neurotoxicity.
POSTER #58 Social experience influences responses to reflection in Drosophila melanogaster Holly Y. May, PhD Candidate, Brock University; A. Joffre Mercier, PhD, Brock University Our lab is interested in how different sensory modalities influence behaviour. We have used mirrors to investigate the role of visual cues in behaviour by measuring responses to reflection. We have examined how Drosophila melanogaster responds to its mirror image and questioned if that response is dependent on social experience. Adult male Canton S fruit flies were either isolated as pupae or raised in a community vial of males and females. Each fly was observed for 20 min in a square chamber made up of two glass walls and two mirrored walls. Three behaviours (rear leg rubbing, abdominal taps and time stopped) were influenced by reflection in isolated flies, whereas no behaviours were altered in socialized flies. Frequencies of double wing flapping and rear leg rubbing were significantly different between isolated and socialized flies, regardless of reflection. Our results suggest that reflection alters behaviour only in socially isolated flies, and that socialization or isolation alters both reflection-dependent and reflectionindependent behaviours in male fruit flies. Future work will focus on how socialization influences courting and grooming behaviours. Research was supported by NSERC.
POSTER #59 ROLE OF THE LATERAL ORBITOFRONTAL CORTEX IN THE DEVELOPMENT AND EXPRESSION OF QUINPIROLE-INDUCED COMPULSIVE CHECKING IN RATS Thomas McMurran1, Derek Ng2, Tiffany Chan3, Dawn Graham4, Henry Szechtman4 1
Graduate Student, Medical Sciences; 2Undergraduate Student, Honours Biology; Undergraduate Student, Bachelor of Health Sciences; 4Department of Psychiatry and Behavioural Neurosciences, McMaster University.
Rats treated chronically with the dopamine D2/D3 agonist quinpirole (QNP) exhibit compulsivelike checking behaviour in an open field arena, a behaviour that might represent an animal model of obsessive compulsive disorder (OCD) (Szechtman et. al., 1998). To date, the pathophysiology of OCD is unknown, however functional imaging studies suggest that there are metabolic abnormalities in the orbitofrontal cortex (OFC), anterior cingulated cortex (ACC) and the caudate nucleus in OCD patients (Rauch et al., 1994). Hyperactivity of the OFC has been the most consistent finding in a number of experiments. The OFC is a heterogenous structure located in the prefrontal cortex that receives projections from all sensory modalities. Specifically, the lateral sub-region of the OFC contains strong reciprocal connections with both limbic and subcortical structures, namely the basolateral amygdala (Schoenbaum et al., 1998) and the nucleus accumbens core (Lynd-Balta, 1995). This places the OFC in a unique position to integrate environmental information to guide behaviours. Given the neuroanatomical and functional imaging evidence, the present study addressed the question whether the lateral OFC is involved in the development or the expression of QNP-induced compulsive checking. The study was broken down into two experiments. (i) To study the expression of compulsive checking, male rats received eight QNP (0.5 mg/kg, twice weekly) or an equivalent saline regimen and behavioural activity in the open field was recorded for 55 minutes after each treatment. Following sensitization, bilateral excitotoxic lesions were centered on the lateral OFC using N-methyl-D-Aspartate (0.35 ÂľL/hemisphere). After recovery, behavioural testing resumed for an additional six treatments. (ii) In the development experiment, lesions were done before the QNP regimen. After recovery, rats received equivalent treatments as the expression experiment. Results showed that expression of QNP-induced checking was slightly reduced in lateral OFC-lesioned animals as measured by number of returns and number of stops before returning to key place one. Findings from the animal model indicate that the lateral OFC appears to affect the time interval between successive checking bouts suggesting that the lesions exerts an anxiolytic effect. References Szechtman H, Sulis W & Eilam D. Quinpirole induces compulsive checking behaviour in rats: A potential animal model of obsessive-compulsive disorder (OCD). Behavioural Neuroscience, 1998; 112:1475-1485. Rauch SL, Jenike MA, Alpert NM, Baer L, Breiter HC, Savage CR, Fischman AJ. Regional cerebral blood flow measured during symptom provocation in obsessive-compulsive disorder using oxygen 15-labeled carbon dioxide and positron emission tomography. Archives of General Psychiatry, 1994; 51(1):62-70. Schoenbaum G, Chiba AA, Gallagher M. Orbitofrontal cortex and basolateral amygdala encode expected outcomes during learning. Nature Neuroscience, 1998; 1(2):155-159.
POSTER #60 Transcriptional Activation of Kisspeptin Neurons and Glutamatergic Inputs to Kisspeptin During the Preovulatory GnRH Surge of the Sheep Christina Merkley, MSc Student, Graduate Program in Neuroscience, U. of Western Ontario, Lique M. Coolen, PhD, Department of Anatomy and Cell Biology, U. of Western Ontario, Leslie Jackson, PhD, Reproductive Sciences Program, U. of Michigan, Robert Goodman, PhD, Department of Physiology and Pharmacology, West Virginia University, and Michael N. Lehman, PhD, Department of Anatomy and Cell Biology, U. of Western Ontario Kisspeptin neurons have been implicated as important mediators of steroid hormone feedback to GnRH cells. Our recent work using the sheep as a model has suggested that kisspeptin cells of the arcuate nucleus (ARC) play a key role in estradiol (E2) negative feedback (1). Based on evidence that there is an increase in kisspeptin mRNA in the ARC during the early follicular phase of the estrous cycle (2), we examined whether these neurons may also be involved in the positive feedback ability of E2 to induce a preovulatory GnRH surge. First, we asked whether kisspeptin cells in the ARC were transcriptionally activated during the GnRH/LH surge, using Fos as a marker. We used a physiological model of the follicular phase, in which ovariectomized ewes receive subcutaneous implants that produce a rise in E2 sufficient to trigger a GnRH/LH surge (3), with ewes perfused 18 hours after E2 implant. Blood samples were taken every 2 hours from these animals from the time of the implant until perfusion. Dual-label immunocytochemistry for Fos and kisspeptin was performed on hypothalamic sections from animals which were perfused either before (pre-surge, n=3) or after the onset of the LH surge (surge, n=3), based on examination of LH patterns. The percentage (mean ± SEM) of kisspeptin cells expressing Fos in the POA and was significantly higher in the surge animals (78± 9.1; 57.0 ± 18.1) compared to the pre-surge group (4.4± 2.6; 18.9 ± 4.1). In addition, there was a trend toward a decreased number of kisspeptin cells, and density of kisspeptin fibers, in the ARC of the surge group compared to pre-surge animals. Because Fos activation is often a result of increased presynaptic glutamate, we examined whether kisspeptin neurons of the ARC possessed glutamatergic inputs using the vesicular glutamate transporters, vGLUT-1 and vGLUT-2, as markers. Using alternate sections, we saw many examples of both vGLUT-1 and vGLUT-2 terminals in close contact with kisspeptin ARC fibers and cell bodies. In addition, we found many instances of terminals containing GAD, a marker for GABAergic terminals, in contact with kisspeptin cells in the ARC. In summary, this study provides evidence for activation of ARC kisspeptin cells during the LH surge suggesting that ARC kisspeptin is involved in conveying the positive feedback action of estradiol to the GnRH neuron. References 1. Goodman et al., Endocrinology 2007; 148(12): 5752 2. Estrada et al, J Neuroendocrinology 2006; 18: 806 3. Evans et al., Endocrinology 1996; 137(11):4730
POSTER #61 EVIDENCE FOR SUSTAINED IMPROVEMENT IN MEMORY DEFICITS FOLLOWING COMPUTER-ASSISTED COGNITIVE REMEDIATION IN PATIENTS WITH A MOOD DISORDER Liesel-Ann Meusel, Ph.D. Student, Graduate Studies in Neuroscience; Margaret McKinnon, Ph.D., McMaster University; Geoffrey Hall, Ph.D., McMaster University; Glenda MacQueen, M.D., Ph.D., University of Calgary Objectives: Major depressive disorder (MDD) and bipolar disorder (BD) are characterized by impairments in cognitive performance across multiple domains. These deficits can persist into the euthymic state, and a large percentage of remitted patients fail to achieve pre-morbid levels of functioning (Fagiolini et al., 2005). Cognitive remediation therapies have been successfully implemented for patients with schizophrenia, however only one study has explored their efficacy for patients with MDD (Elgamal et al., 2007). We are extending these preliminary findings to investigate the efficacy of a computer-assisted cognitive remediation (CACR) program for mood disorder populations. We expect patients to show improved cognitive performance immediately following the 10-week program, and we expect gains to be maintained after 3-months. Methods: Patients with MDD or BD completed a 10-week CACR program. This intervention involved administration of five software packages aimed at improving performance across four domains: attention, memory, psychomotor speed, and executive function. Cognitive functioning was assessed with a battery of standardized neuropsychological tests at baseline, at completion, and at 3-months follow-up. Results: This study is in progress; results are preliminary. Repeated-measure ANOVAs and paired-sample t tests showed sustained improvement on memory tasks in patients (n = 12) relative to controls (n = 12), including delayed verbal recall, verbal retention, working memory, and implicit learning. Conclusions: Findings from this study will help establish the utility of cognitive remediation programs for patients with a mood disorder. Implementation of such programs may eventually translate into decreased medical-related disability and better functional outcome for patients with illness-related cognitive impairment. Literature References: Fagiolini, A., Kupfer, D.J., Masalehdan, A., Scott, J.A., Houck, P.R., & Frank, E. (2005). Functional impairment in the remission phase of bipolar disorder. Bipolar Disorders, 7, 281-285. Elgamal*, S., McKinnon*, M.C., Ramakrishnan, K., Joffe, R.T., & MacQueen, G. (2007). Successful computer-assisted cognitive remediation therapy in patients with unipolar depression: a proof of principle study. Psychological Medicine, 1-10.
POSTER #62 Mechanisms underlying modulation of muscle contraction by a Drosophila neuropeptide Maja Milakovic, M.Sc. Student, Department of Biological Sciences, Brock University; Julie Clark, PhD, York University; A. Joffre Mercier, PhD, Professor, Brock University The most abundant of the Drosophila melanogaster FMRFamide peptides, DPKQDFMRFamide, has been shown to enhance nerve-evoked muscle contractions and to increase tonus in larval muscles by acting directly on the muscle fibers. Genetic studies have identified and sequenced a G protein coupled receptor for FMRFamides in adult Drosophila flies and larvae. Hence, it is hypothesized that DPKQDFMRFamide can act both, presynaptically and postsynaptically, through the dFMRFamide G protein coupled receptor. The current work investigated which secondary messenger pathways are involved in mediating peptideâ€™s postsynaptic effect on muscle tonus. We utilized pharmacological and genetic manipulations to investigate whether or not cAMP, phospholipase C (PLC), inositol triphosphate (IP3) and calcium/calmodulindependent protein kinase II (CaMKII) are required for the DPKQDFMRFamide-induced muscle contractions. We also used enzyme immunoassays to measure intracellular cAMP levels in the presence of the peptide. DPKQDFMRFamide does not increase cAMP levels in larval body wall muscles, nor is the peptide's effect on tonus potentiated in the presence 3-isobutyl-1methylxanthine, a phosphodiesterase inhibitor. Application of 10 'M Rp-cAMPS, a protein kinase A inhibitor, did not affect the muscle's response to the peptide. The effect of DPKQDFMRFamide on muscle tonus in mutant Drosophila larvae with reductions in phospholipase C-" (PLC) or inositol triphosphate receptor (IP3R) was similar to the response in wild type larvae. The reduction of calcium/calmodulin-dependent protein kinase II (CaMKII) activity in ala1 transgenic flies did not suppress the response to peptide. These results suggest that cAMP, IP3 and CaMKII are not involved in mediating the postsynaptic effect of DPKQDFMRFamide. Supported by NSERC.
POSTER #63 Genes, Environment, and Maternal Behaviour Viara Mileva-Seitz, Ph.D. candidate, Institute of Medical Science, University of Toronto; James Kennedy MD, Ph.D., University of Toronto; Leslie Atkinson, Ph.D., Ryerson University; Marla B Sokolowski, Ph.D., University of Toronto at Mississauga; Meir Steiner, MD, McMaster University; Alison Fleming, Ph.D., University of Toronto at Mississauga† †A MAVAN project, PIs: Michael Meaney, Stephen Matthews We investigated variation in the human serotonin promoter polymorphism (5HTTLPR) and early life experiences, in association with maternal behaviour in 202 mothers at 6 months postpartum. Mothers were assessed for mood (Edinburgh Postpartum Depression Scales, EPDS), experience being parented in childhood (Parental Bonding Instrument, PBI), and childhood abuse/neglect (Childhood Trauma Questionnaire, CTQ). Twenty-minute recordings of motherinfant non-nursing interaction were later coded for frequency and duration of maternal behaviours (e.g. look-away from infant; touch; vocalize), and maternal sensitivity (using the Ainsworth Sensitivity Scales). DNA was collected with buccal swabs, extracted, and genotyped at 5HTTLPR, a triallelic polymorphism: the A-variant of the long allele (LA) is associated with higher 5HTT expression than the G-variant (LG) and short (S) alleles. There were no differences in maternal behaviour between mothers scoring low versus high on PBI or CTQ, but there were independent effects of genotype: LALA moms were less sensitive and looked away from their infants more often than moms of other genotypes. Genotype X PBI and genotype X CTQ effects were significant for duration of maternal vocalization: LALA moms’ vocalization duration was experience-independent, whereas other genotypes vocalized less in the presence of early adversity (low PBI or high CTQ). The effects remained when depression score (EPDS), age, and income were co-varied. In the past, the long allele has been considered the “resilience” allele; on the other hand, our results suggest the LG and S alleles are susceptibility alleles – associated with greater responsivity to environmental effects.
POSTER #64 Abnormal hippocampal activation in patients with minimal or extensive past history of major depression: An fMRI study Andrea M.B. Milne, BSc 1,2, Geoffrey B.C. Hall, PhD 2,3, Glenda M. MacQueen MD, PhD 2,4 1
PhD Student, Medical Sciences; 2Department of Psychiatry and Behavioural Neurosciences, McMaster University; 3Brain Body Institute, St. Joseph's Healthcare Hamilton; 4Department of Psychiatry, University of Calgary Dysfunction in various memory systems have been identified in Major Depressive Disorder (MDD). Impairments on recollection memory tests are consistently reported in MDD (MacQueen et. al., 2002). These abnormalities may reflect the underlying hippocampal volume changes observed in MDD, particularly in patients with a protracted course of illness (McKinnon et. al., 2009). The aim of the present study was to use functional magnetic resonance imaging (fMRI) to examine the effects of illness duration on hippocampal activation during recollection memory trials. Patients presenting for first treatment of MDD (N = 11, mean age 26.91 + 8.36), were compared to patients who had experienced three or more past episodes of MDD (N = 11, mean age 49.4 + 8.24). Age and sex matched controls were recruited for both groups. All subjects took part in an fMRI recollection memory task. Using region of interest analysis isolating the hippocampus we observed a greater recruitment of the HC in the first treatment MDD group in comparison to controls during recollection memory trials. The multiple episode MDD group showed decreased recruitment of the HC in comparison to controls on recollection memory trials. The findings of greater recruitment at first episode, and decreased recruitment after multiple episodes suggest that the hippocampus is sensitive to the impact of disease burden and repeated episodes of MDD. Furthermore, greater recruitment of the HC in first treatment patients raises the possibility that patients are able to engage compensatory processes during the early stages of illness that are attenuated with repeated episodes of illness.
References MacQueen, G.M., Galaway, T.M., Hay, J., Young, L.T. & Joffe, R.T. (2002). Recollection memory deficits in patients with major depressive disorder predicted by past depressions but not current mood state or treatment status. Psychol. Med. 32; 251-258 McKinnon, M.C., Yucel, K., Nazarov, A. & MacQueen, G.M. (2009). A meta-analysis examining clinical predictors of hippocampal volume in patients with major depressive disorder. J Psychiatry Neurosci. 34(1): 41-54
POSTER #65 PKC Inhibition Increases Gap Junction Intercellular Communication and Cell Adhesion in Human Neuroblastoma Melissa Morley1, Claire Jones1, Vishal Gupta1, Mandeep Sidhu1, Suzanne M. Bernier1, Walter J. Rushlow1,2 and Daniel J. Belliveau1,3,Âś 1
Department of Anatomy and Cell Biology, Faculty of Medicine & Dentistry; 2Department of Psychiatry, London Health Sciences Centre â€“ University Campus and 3Bachelor of Health Sciences Program, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada, N6A 5C1 Gap junction intercellular communication and cell-cell adhesion are essential for maintaining a normal cellular phenotype, including the control of growth and proliferation. Loss of either cellcell adhesion or communication is common in cancers, while restoration of function is associated with tumour suppression. Protein kinase C (PKC) isozymes regulate a broad spectrum of cellular functions including growth and proliferation and their overexpression has been correlated with carcinogenesis. Consequently, PKC inhibitors are currently undergoing clinical trials as an anti-cancer agents although the precise cellular alterations induced by PKC inhibitors remains to be elucidated. In the current study, the effects of PKC inhibitors on cell interactions were investigated using human neuroblastoma (IMR32, SKNMC, and SHSY-5Y) cell lines. An analysis of intercellular communication revealed an increase in gap junctional coupling with PKC inhibition. The observed increase in coupling was not associated with a change in Connexin43 distribution or an alteration of phosphorylation status of the protein. There was also an increase in cell-cell adhesion with PKC inhibitor treatment as indicated by a cell aggregation assay. Therefore, the growth suppressive abilities of PKC inhibition on tumours may be due to the cancer suppressive effects of increased gap junction intercellular communication and cell-cell adhesion.
POSTER #66 Elevated Intracellular Calcium Up-regulates Mitochondrial Protein Import in Differentiated PC12 Cells and in Rat Cortical Neurons Adrian P. Nahirny, M.Sc. Student1,3, Jamie Fong, M.Sc.1,3, and Linda R. Mills, PhD1,2,3. Department of Physiology1, Faculty of Medicine2, University of Toronto, Division of Genetics and Development TWRI University Health Network3, Toronto, Ontario, Canada, M5T 2S8
>99% of mitochondrial proteins are nuclear-encoded and must be imported into mitochondria. Deficits in mitochondrial protein import (MPI) will impact virtually every aspect of mitochondrial function, but little is known about how it is regulated in neurons. We hypothesized that a sustained increase in basal Cai2+ will increase MPI. To increase Cai2+ we used the Ca2+ ionophore, A23187 and measured the import of 4 proteins; (a) mtGFP, an inducible GFP fusion protein targeted to mitochondria, (b) mtHSP70, a mitochondrial matrix chaperone, (c) mtTFA, a mitochondrial transcription factor, and (d) Tom20, a key MPI receptor. MPI was evaluated by western blots of mitochondrial fraction and in live cells mtGFP import and intramitochondrial turnover were measured by flow cytometry (Sirk et al 2003; 2007). Cell viability was measured by MTT reduction and cell death by PI. Results: A23187 increased mtGFP import in a dose dependent manner (0.1-0.5 M), however 0.5 M A23187 caused cell death. In contrast 0.15 M A23187 decreased MTT reduction by 26% +/- 3 (n=3) but did not cause cell death. A23187 for 24 hrs increased mtGFP import by 20% +1 (n=3), while a 24h exposure to A23187, followed by 24h of normal media increased mtGFP import by 78% +/- 3 (n=3). Similarly, exposure to A23187 for 48h increased mtGFP import by 73% +/- 3 (n=3).Intramitochondrial mtGFP half-life was 52h in controls but 70h in cells treated with A23187 (n=2) indicating that A23187 slowed intramitochondrial mtGFP turnover. Western blots confirmed that A23187 had selective effects on MPI in PC12 cells; by 48 hrs mtGFP, mtHsp70 and mtTFA increased versus controls but Tom20 levels were unchanged. In cortical neurons 24 hrs of A23187 increased mtHsp70 import but mtTFA and Tom20 were unaffected. These findings demonstrate that in neurons sustained increases in Cai2+ levels can differentially upregulate the import of nuclear encoded mitochondrial proteins.
(This study was funded by CIHR, NSERC to LRM OGS to JF)
POSTER #67 The Impact of Intestinal Microbiota on Anxiety-like Behaviour Karen-Anne M. Neufeld1, John Bienenstock2, and Jane A. Foster3 1. PhD Student, Medical Sciences Graduate Program, McMaster University 2. Department of Medicine, Pathology & Molecular Medicine and Brain-Body Institute, St Josephâ€™s Healthcare 3. Department of Psychiatry & Behavioural Neurosciences, McMaster University and BrainBody Institute, St. Josephâ€™s Healthcare INTRODUCTION: Brain-gut communication has long been recognized as a significant contributor to gastrointestinal function and dysfunction, especially in the study of functional bowel disorders. Indeed, more than 50% of patients suffering from irritable bowel syndrome (IBS) also meet criteria for psychiatric illness, with particular emphasis on anxiety disorders and depression (Whitehead et al., 2002). Interestingly, a growing body of evidence demonstrates that patients suffering from IBS demonstrate an altered intestinal microbial profile suggesting that dysfunction may relate directly to the microbiota present. Germ free (GF) mice are raised and maintained with no commensal intestinal microbiota. Work by others has demonstrated increased stress reactivity in GF mice. In comparison to specific pathogen-free (SPF) mice, GF mice show increased hypothalamic-pituitary-adrenal activation (HPA), with elevated plasma adrenocorticotropin hormone and corticosterone in response to immune challenge or restraint stress (Sudo et al., 2004). To date, no behavioural phenotype for GF mice has been documented. OBJECTIVES: The objective of this experiment was to examine basal anxiety-like behaviour in adult GF mice both before and after conventionalization with intestinal microbiota. METHODS: 8-week-old Swiss Webster GF mice and 8-week-old Swiss Webster SPF mice were tested for anxiety-like behaviour in the elevated plus maze (EPM). Following testing, GF animals were housed under SPF conditions and exposed to SPF feces for 2 weeks. All animals were then retested in the EPM. RESULTS: Adult GF mice spend significantly more time in the open arms of the EPM compared to SPF controls. Reconstitution of SPF microflora to GF mice did not alter this behavioural phenotype as GF/SPF mice spent significantly more time in the open arms of the EPM following reconstitution, compared to SPF controls. CONCLUSION: The persistent nature of this behavioural phenotype following reconstitution suggests that early developmental interactions between the gut microflora and the brain contribute to long-term changes that influence the trait anxiety of the adult mouse. The presence or absence of gut microbiota has a defining impact on the development and function of the central nervous system. REFERENCES: Sudo, N., Chida, Y., Aiba, Y., Sonoda, J., Oyama, N., Yu, X.N., Kubo, C., Koga, Y., 2004. Postnatal microbial colonization programs the hypothalamic-pituitary-adrenal system for stress response in mice. J Physiol 558, 263-275. Whitehead, W.E., Palsson, O., Jones, K.R., 2002. Systematic review of the comorbidity of irritable bowel syndrome with other disorders: what are the causes and implications? Gastro 122, 1140-1156
POSTER #68 Mild Head Injury in University Students: Physiological Anticipation, Decision-Making, and Contemplation in Social Dilemmas van Noordt, S.1, BA (Hons.) Candidate, & Good, D.2, Ph.D., C. Psych. 1
Department of Psychology, Brock University Department of Psychology and Centre for Neuroscience, Brock University
The constellation of impairments after head trauma, including affective, behavioural, and cognitive dysfunction, produce serious complications across the lifespan. Research into milder forms of head trauma indicates that functional disruption of brain activity may be sufficient in creating noticeable deficits in performance. Importantly, affective and cognitive symptoms are likely to be residual, and often very subtle, where physical problems tend to dissipate with time. Furthermore, recent findings suggest that lower performance in cognitive and emotional domains in those reporting mild head injury (MHI) can be evinced in highly competent university populations. The purpose of this research was to investigate the relationships between neuropsychological performance, physiological arousal, and decision-making in university students with and without a history of MHI. A total of 44 university students (41% reporting MHI) engaged in an executive function test, the Iowa Gabling Task (IGT; Bechara, 2007), and made decisions for social dilemmas of varying moral relevance, while having electrodermal responses (EDRs) recorded. As expected, cognitive performance did not differ between groups. Also, overall IGT performance (100 trials) was not significantly different between the MHI and nonMHI groups. Although both groups exhibited obvious learning over the first half of the IGT, performance for the MHI group was more variable for the remainder of the task. Physiological responses to outcome feedback (i.e. win or loss) indicate that persons with MHI have the capacity to be emotionally aroused, in a reactive way, comparable to those in the non-MHI group. Despite these patterns in behavioural and electrophysiological data, persons with MHI were significantly less physiologically aroused when anticipating making decisions (p < .05), demonstrating partial support for the Somatic Marker Hypothesis (Bechara et al., 1996). Without activating or stress-inducing triggers, persons reporting a previous MHI, have a lower state arousal than persons who do not. Further, when presented with ambiguous situations, students who report an MHI make decisions more quickly than their cohorts (p < .06) and, have a tendency to do so particularly for decisions that are riskier (regardless of the magnitude of the loss) (p < .10). Together, these findings have important implications for understanding the mechanisms behind the decision-making process in highly competent populations with milder forms of head trauma. Persons who have experienced an MHI may be emotionally/physiologically less informed when making decisions than those who have not. In being limited in experiencing emotional markers when anticipating potential outcomes, followed by inconsistent learning patterns, the stage could be set for poorer decision-making. Further, having not anticipated the outcomes, an overreactivity to outcomes is possible (depending on the circumstances) which may be deemed socially incompatible â€“ a finding observed in social interactions for some persons with severe traumatic brain injury (TBI). Overall, these findings mirror results obtained by persons with more serious brain injuries and encourage the acceptance of MHI as being on a continuum of brain injury severity as opposed to there being categorical divisions of neural trauma severity. The neurophysiological profile of MHI can emulate features of more traumatic cases, even in cognitively competent University students, including the altered role of physiological/emotional input in decision making contexts.
POSTER #69 Does thermal acclimatization alter effects of a cholesterol chelator on synaptic transmission and impulse propagation? Kiel Ormerod, H BSc Student, Brock University; A. Joffre Mercier, PhD, Professor, Brock University Temperature acclimatization alters concentrations and distribution of lipid constituents in cellular membranes. Cholesterol, a component of cellular membranes, increases curvature and rigidity of membranes and is an integral component of lipid rafts. Exocytosis of transmitters at synaptic boutons requires the synchronized action of several proteins linked to lipid rafts. The cholesterol chelator, methyl-ß-cyclodextrin (MßCD), is reported to increase transmitter release from directly stimulated boutons in crayfish and to block impulse propagation in axons. Preliminary data from our lab suggested that acclimatization to different temperatures alters the effects of MßCD on excitatory junctional potentials (EJPs). The goal of the present work was to determine whether the effects of MßCD on impulse propagation and synaptic transmission are dependent upon acclimatization temperature. Procambarus clarkii were acclimatized to 14oC and 21oC for a minimum of 2 weeks, after which loose patch and intracellular recordings were made simultaneously from crayfish deep abdominal extensor muscles to assess the effects of MßCD on EJPs, nerve terminal currents and synaptic currents over a 10 minute period. 10 mM MßCD caused a significant transient increase in EJP amplitude in both cold and warm-acclimatized preparations (P<0.05). The transient rise occurred significantly faster in warm-acclimatized trials (P<0.05). In cold acclimatized trials the transient rise in EJP amplitude was followed by a significant reduction in EJP amplitude (P<0.05), which coincided with a significant reduction in the amplitude of the nerve terminal current (P<0.05) and a significant reduction (P<0.05) in the average number of quanta released per nerve impulse (quantal content). In warm-acclimatized crayfish, however, the transient increase in EJP amplitude was followed by a return to control EJP levels. During this time, there was no change in the amplitude of nerve terminal currents (P>0.05), but there was a continued increase in quantal content (P<0.05). Thus, lowering acclimatization temperature makes axons more susceptible to impulse failure, resulting in reduction of transmitter output within 10 min of MßCD treatment. Warm acclimatization does not render axons more susceptible to impulse failure, which prevents the reduction in transmitter output over the same time period. Supported by NSERC.
POSTER #70 Finger size, not sex, determines tactile spatial acuity Ryan M. Peters, M.Sc. student, Graduate Studies in Psychology, Neuroscience & Behaviour, Daniel Goldreich, Ph.D. McMaster University Passive tactile spatial acuity, the ability to resolve the spatial structure of surfaces pressed upon the skin, differs subtly between the sexes, with women able to perceive finer surface detail than men. The cause of this sex difference in the sense of touch is unknown. Recent anatomical findings suggest that cutaneous receptor number may be conserved across individuals; if so, in smaller fingers cutaneous receptors would be more densely packed, conferring finer tactile acuity. The objectives of this study were to test the hypotheses that 1) finger size determines tactile acuity, and 2) women have better tactile spatial acuity than men simply because women tend to have smaller fingers. We measured index fingertip surface area in 50 men and 50 women (18-24 years old), then tested all subjects on a fully automated two-interval forced-choice grating orientation task (GOT), a rigorous measure of passive tactile spatial acuity. The dominant index fingertip was contacted twice, with grooves of equal width but orthogonal orientations (order randomized; 50 g contact force). A Bayesian adaptive procedure estimated the width of the grooves whose orientation the subject could distinguish with 76% probability (d-prime = 1). In a subset of participants, we additionally measured sweat pore spacing, a possible correlate of cutaneous receptor density. Merkel cells, the putative mechanotransducers for statically impressed stimuli, tend to cluster around the bases of sweat pores in the deep epidermis. Each slowly adapting type 1 (SA1) afferent innervates a group of Merkel cell clusters. To measure pore spacing, we coated the distal finger pad with a water-soluble paint, which settles into the pores, then scanned at high resolution (2400 dpi). In agreement with previous studies, the women in the present study had significantly better tactile spatial acuity than the men. However, this apparent sex effect was fully accounted for by the effect of finger size. Finger size positively correlated with tactile thresholds across the entire subject sample and within each sex individually; a sex by fingertip area ANCOVA revealed a significant main effect of finger size, but not of sex; and Bayesian model comparison strongly supported the hypothesis that tactile thresholds depend on finger size rather than sex. Thus, when finger size is considered, the apparent sex effect on acuity disappears. Sweat pore spacing also positively correlated with finger size: smaller fingers had more densely packed pores. We conclude that finger size, and not sex, determines tactile spatial acuity. Smaller fingers probably have greater Merkel cell and SA1 receptor density, and consequently better acuity. Much variance in the acuity data remains unexplained, and the influence of finger size does not preclude the concomitant influence of other factors, such as skin conformance and hydration.
POSTER #71 CORRELATION OF MALE MONGOLIAN GERBIL SOCIAL BEHAVIOURS WITH ESTROGEN RECEPTOR ALPHA AND OXYTOCIN EXPRESSION IN THE BRAIN Phan, A. MSc, PhD Student, Dept. of Biomedical Sciences, Dept. of Psychology, University of Guelph; Roberts, V.M. BSc, Dept. of Biomedical Sciences, University of Guelph; Abadilla, R. BSc, Dept. of Biology, Dept. of Psychology, McMaster University; Mong, J.A. PhD, Dept. of Pharmacology and Experimental Therapeutics, University of Maryland; Choleris, E. PhD, Dept. of Psychology, University of Guelph; Clark, M.M. PhD, Dept. of Psychology, McMaster University. Mongolian gerbils (Meriones unguiculatus) are a biparental, social species. Both the male and female contribute to rearing their pups. We investigated the potential involvement of estrogen receptor alpha (ER!) and oxytocin (OT) in various social behaviors (i.e. parental behavior, social investigation, scent marking) and physiological measures (i.e. body weight, testes weight). Following behavioral testing, 57 males gerbil brains were extracted, and immunocytochemistry for ER! and OT were performed. The density of cells stained for ER! or OT in various brain nuclei were measured using ImageJ and correlated with behavioral measures using SPSS. ER! expression in the hypothalamic ventral medial nucleus negatively correlated with the amount of time fathers spent away from their pups, while preliminary results suggest that OT staining in the paraventricular nucleus is positively correlated to the amount of time fathers spend with their pups. ER! expression in the amygdala as well as OT expression in the periventricular and paraventricular nucleus negatively correlated with social investigation times. These results suggest that both OT and ER! may be involved in the regulation of male parental behavior and other social behaviors in Mongolian gerbils. Funded by NSERC.
POSTER #72 DELTAFOSB IN THE NUCLEUS ACCUMBENS REGULATES SEXUAL EXPERIENCE Kyle K. Pitchers, PhD student, University of Western Ontario; Karla S. Frohmader, PhD student, University of Western Ontario; Vincent Vialou, PhD, Mount Sinai School of Medicine; Eric J. Nestler, MD, PhD, Mount Sinai School of Medicine; Lique M. Coolen, PhD, University of Western Ontario Sexual motivation and reward are mediated by the mesocorticolimbic system, in which the nucleus accumbens (NAc) plays a central role. However, there is little known about the specific cellular and molecular mechanisms underlying the rewarding and reinforcing effects of sexual behavior. DeltaFosB, the truncated form of FosB, is a unique member of the Fos family of transcription factors due to its greater stability. DeltaFosB persists in cells following the cessation of a chronic stimulus which is suggestive of a role in long-term neuroplasticity. Furthermore, it has been found to be up-regulated in distinct brain regions following the repeated administration of drugs of abuse and natural rewards. In the current study, we investigated the effects of repeated sexual behavior on DeltaFosB levels in the brains of male rats. Adult male Sprague Dawley rats were either mated to one ejaculation in five daily consecutive mating sessions (sexually experienced) or remained na誰ve, handled controls (sexually na誰ve). Animals were perfused 18-24 hours following the last mating session and brains were immunoprocessed for DeltaFosB. Results demonstrated that sexual experience upregulates DeltaFosB in the NAc. Next, DeltaFosB in the NAc was manipulated using viralmediated gene transfer to study its potential role as a mediator of sexual experience. Sexually na誰ve adult male Sprague Dawley rats received bilateral microinjections of recombinant adenoassociated viral (rAAV) vectors encoding green fluorescent protein (GFP), wild-type DeltaFosB or a dominant-negative binding partner of DeltaFosB (referred to as DeltaJunD) into the NAc. Results showed that animals with DeltaFosB overexpression displayed a more rapid sexual facilitation with experience indicated by an increased copulation frequency relative to GFP controls. In contrast, DeltaJunD overexpression attenuated sexual facilitation responses with sexual experience, as these males displayed increased mount, intromission and ejaculation latencies compared to GFP and DeltaFosB groups. Together, our findings suggest that DeltaFosB in the NAc is critical for the reinforcing effects of sexual behavior.
POSTER #73 PHARMACOLOGICAL RESCUE OF NONSENSE MUTATIONS IN RETT SYNDROME Andreea Popescu 1, 2 , G. Zhang 2, 3 , J. Eubanks 1, 2, 3, 4 Department of Physiology 1 , Division of Genetics and Development, Toronto Western Research Institute 2 , Institute of Medical Sciences 3 , Division of Surgery 4 , Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8. Rett Syndrome, the most common genetic cause of mental retardation in girls worldwide, is caused by loss of function mutations in the gene encoding the transcriptional regulator MeCP2. Approximately 40% of Rett Syndrome cases arise from nonsense mutations in which a stop codon is introduced into the open reading frame of MeCP2 generating a truncated protein. Several studies have shown that a class of antimicrobial drugs known as aminoglycosides facilitate the ribosomal complex to â€œread-throughâ€? some types of nonsense mutations, generating a full length protein. However, the efficiency of aminoglycoside-mediated readthrough varies for different nonsense mutations, and it is not clear whether or how Rett syndrome mutations will respond to treatment. The aim of this study was to test whether the premature terminating mutations of MeCP2 that cause Rett Syndrome can be suppressed by aminoglycoside administration allowing a full length MeCP2 protein to be generated. To test this hypothesis we have obtained lymphoblast cell lines from Rett girls containing the arginine mutation, which is also the most prevalent nonsense mutation seen in Rett Syndrome patients. Nuclear extracts from cells treated with and without different concentrations of aminoglycosides were examined by Western Blotting for the presence of MeCP2 protein. Treatment of lymphoblasts for four days with the aminoglycosides gentamicin, geneticin and amikacin restored the full length MeCP2 protein in a dose response manner. Consistently, full length MeCP2 protein was detected in HEK cells transiently transfected with mutant MeCP2 cDNAs when they were treated for 48 hours with aminoglycosides. However, the efficiency of read through was highly dependent on the context of the nonsense mutation and the aminoglycoside tested with geneticin having the highest read through. Taken together, these results suggest that aminoglycoside-induced read through of nonsense MeCP2 mutations is possible, and provide a novel direction for developing new treatments for this insidious neurological condition that affects young girls.
POSTER #74 MECHANISMS INVOLVED IN MELATONIN-INDUCED HISTONE H3 HYPERACETYLATION IN CULTURED NEURAL CELLS Paulina A. Rzeczkowska1, Lennard P. Niles2 1
B.Sc. Student, Undergraduate Studies in Honours Biology and Psychology, Department of Psychiatry & Behavioural Neurosciences, McMaster University
Novel evidence reported by our group suggests a role for melatonin, a pineal indoleamine hormone, in epigenetic modulation of gene expression. At physiological doses, melatonin can induce chromatin remodelling in mouse C17.2 neural stem cells (NSCs), seen as histone H3 hyperacetylation, which is associated with gene transcription (Sharma et al, 2008). We have also reported that melatonin plays a role in cellular differentiation of C17.2 NSCs towards a neuronal phenotype (Sharma et al, 2008), and it induces neuroprotective gene expression in these cells as well as in human SH-SY5Y neuroblastoma (McMillan et al, 2007) and rat C6 glioma cells (Armstrong & Niles, 2002). This study aims to investigate 1) if melatoninâ€™s ability to induce histone acetylation in neural stem cells is preserved across species by examining the concentration-dependent effects of melatonin on histone H3 acetylation in rat C6 glioma and human SH-SY5Y neuroblastoma cells; and 2) the mechanisms involved in its induction of acetylation and subsequent gene expression by examining the concentration-dependent effects of melatonin on the mRNA expression of histone acetyltransferases p300 and CBP in cultured C17.2 NSCs. Melatonin up-regulated histone H3 acetylation in SH-SY5Y cells differentiated by retinoic acid. A trend toward increased H3 acetylation was seen in undifferentiated SH-SY5Y cells, but not in C6 cells. Rat C6 cells express both the MT1 and MT2 melatonin receptor subtypes (Armstrong and Niles, 2002), whereas mouse C17.2 and human SH-SY5Y cells express only the MT1 subtype (Sharma et al., 2008; McMillan et al., 2007). Melatonin-induced acetylation may be mediated by the MT1 receptor. Melatonin down-regulated CBP mRNA expression. The same trend was seen in p300 mRNA expression. An examination of protein expression and/or activation is needed to clarify the possible involvement of these HATs in melatonin-induced chromatin remodelling. These findings, together with future in vivo studies, will advance our understanding of the mechanisms underlying the physiological effects of melatonin and aid in the optimization of therapeutic strategies in diverse disorders including neurodegeneration.
References Armstrong KJ, Niles LP. Induction of GDNF mRNA expression by melatonin in rat C6 glioma cells. Neuroreport, 2002; 13(4):473-475. McMillan CR, Sharma R, Ottenhof T, Niles LP. Modulation of tyrosine hydroxylase expression by melatonin in human SH-SY5Y neuroblastoma cells. Neuroscience Letters, 2007; 419(3):202-206. Sharma R, Ottenhof T, Rzeczkowska PA, Niles LP. Epigenetic targets for melatonin: Induction of histone H3 hyperacetylation and gene expression in C17.2 neural stem cells. Journal of Pineal Research, 2008; 45(3):277-284.
POSTER #75 Language Processed as Music and the Role of the Left Inferior Frontal Cortex Beyond Phonological Processing Ricardo Reyes, Year 2 B.A. Hon. Student, Institute of Cognitive Science, Carleton University Baddeley's Working Memory Model (1986) incorporates a processing system for auditory stimuli identified as the 'phonological loop'. The specificity of this model will be challenged by a meta-analysis as well as by the proposed study. Linguistic processing from an auditory and visual stimuli perspective is reviewed and some of its neural mechanisms are pointed out. Some theories on the neural substrates of musical perception are then presented. Subsequently, a categorical and neural relationship between music and language is put into view. Lateral activation in musicians is left-hemisphere dominant while in non-musicians it is right-brain dominant. It is suggested that musical processing in highly trained musicians transforms into a linguistic task. It has also been shown that semantic processing tasks in music and language share localized brain areas. It is possible that the neural 'phonological loop' is not only for linguistic stimuli but is rather multi-modal. In a between-subject design, ninety participants will be tested in a total of six conditions seeking to prove that the inferior frontal cortex is involved in the detection of discrete ordered units in a sequence.
POSTER #76 Maternal smoke exposure results in hyperactivity Kelly C. Rilett, MSc Student, Department of Psychiatry, The Brain-Body Institute; Martin R. Stämpfli, PhD, Department of Molecular Medicine and Pathology, The Center for Gene Therapeutics; Jane A. Foster, PhD, Department of Psychiatry and Behavioural Neurosciences, The Brain-Body Institute, St. Joseph’s Healthcare Hamilton, McMaster University Early life stressors are known to impact CNS development and may influence vulnerability to disease in human populations. Our lab utilizes behavioural and molecular tools to understand how these early life challenges alter the trajectory of CNS development. In humans, smoking during pregnancy is associated with psychiatric disorders and Attention Deficit Hyperactivity Disorder (ADHD). The objective of this study was to determine in impact of maternal smoke exposure on exploratory, locomotor, and anxiety-like behaviour in the offspring. Using an established smoking apparatus, we exposed female CD1 mice to smoke for 1 hour twice daily for 4 weeks. We then bred smoke-exposed mice and naïve mice and continued to expose the smoke group through pregnancy. Smoking exposure was stopped when the pups were born. The behaviour outcomes measured in the pups included: social behaviour, general activity levels (open-field), and anxiety-like behaviour (light/dark box and elevated plus maze). All behavioural tests were conducted during adolescence. The pups that were smoke-exposed in utero were hyperactive in the open field but did not demonstrate any significant differences in social behaviour or in anxiety-like behaviour. These data suggest that prenatal smoke exposure can alter activity levels. This finding is of interest given that previous work in humans by other laboratories has shown that children born to smoking mothers are at higher risk to develop ADHD. Again, this suggests that in utero smoke exposure may influence behaviour later in life. To better understand the relationship between maternal smoke challenge and hyperactivity, brain tissue has been collected from these mice in order to conduct molecular analyses.
POSTER #77 ALTERED BRAIN-DERIVED NEUROTROPHIC FACTOR mRNA IN POST MORTEM BRAIN TISSUE OF SUBJECTS WITH NON-ALZHEIMER’S DISEASE TAUOPATHIES SUGGESTS A NOVEL ROLE FOR PATHOLOGICALLY MODIFIED TAU Jillian C. Roberts, B.H.Sc.1, Raheleh Masoudi, Ph.D.2, Margaret Fahnestock, Ph.D.3 1
Graduate Student, Medical Sciences; 2Department of Pathology and Molecular Medicine; 3 Department of Psychiatry and Behavioural Neurosciences, McMaster University.
Alzheimer’s disease manifests as global cognitive decline, altering memory, orientation, and reasoning. Major histological hallmarks include aggregation of the microtubule associated protein tau to form tangles and aggregation of amyloid-" (A") peptide to form plaques. Tau and A" are implicated as potent neurotoxins, but the mechanism by which they cause cell death is still under investigation. Brain-derived neurotrophic factor (BDNF), a neurotrophic factor implicated in neuronal survival, plasticity and memory formation, is down-regulated in Alzheimer’s disease and may mediate losses in synaptic plasticity and memory. Previous studies in our lab demonstrated that oligomeric A" down-regulates BDNF, but whether tau also affects BDNF levels remained unclear. This study investigates the hypothesis that pathological tau is also able to down-regulate BDNF. To test our hypothesis, we used real-time quantitative RT-PCR to measure total BDNF mRNA levels as well as the levels of individual BDNF transcripts in postmortem parietal cortex of subjects with tauopathies compared to age-matched controls. Tauopathies are a class of neurodegenerative diseases including Pick’s disease, corticobasal degeneration and progressive supranuclear palsy which exhibit tau pathology in the absence of A" pathology. We demonstrate a significant down-regulation of BDNF in Pick’s disease and a trend towards down-regulation in corticobasal degeneration. Transcript analysis reveals that several BDNF transcripts, including the most highly expressed transcript IV, contribute to tau-mediated BDNF down-regulation. Importantly, some of the individual transcript changes in Pick’s disease are different from those altered in vitro by A", yet show similarity to those down-regulated in Alzheimer’s disease. Together, these data implicate pathological tau as an important mediator of BDNF down-regulation. Furthermore, transcript analysis suggests that tau and A" may down-regulate BDNF via different mechanisms.
POSTER #78 The Role of Retinoic Acid in Long-Term Memory Consolidation Following Operant Conditioning Cailin M. Rothwell, M.Sc. Student; Gaynor E. Spencer, Associate Professor Department of Biological Sciences, Brock University Retinoic acid (RA), an active metabolite of vitamin A, regulates gene transcription by acting as a ligand for retinoic acid receptors (RARs) and retinoid X (RXR) nuclear receptors. RA is essential for vertebrate development but has also been implicated in learning and memory in adult vertebrates. This study aimed to examine the role of RA in learning and long-term memory consolidation using the mollusc Lymnaea stagnalis following operant conditioning of the welldefined aerial respiratory behaviour. In this study, the RA synthesis pathway was disrupted using citral, a well known retinaldehyde dehydrogenase (RALDH) inhibitor, in order to examine any changes in learning and long-term memory resulting from the depletion of RA levels at various time points. The aerial respiratory behaviour is easy to observe and operantly condition, making it ideal for this research. Furthermore, the adult central nervous system of L. stagnalis is known to contain retinoids and specific retinoid receptors, implying that RA signalling occurs in this species. By altering the timing of citral incubations relative to the training paradigm it was determined that RA was not required for successful learning or maintenance of memory, once it had been formed. However, RA was required during the early stages of training in order for long-term memory to become consolidated. This is the first evidence to support an involvement of RA in long-term memory formation in invertebrates and suggests that the role of RA in memory consolidation is conserved between vertebrates and invertebrates.
POSTER #79 Molecular mechanisms involved in the postnatal loss of hypoxic sensitivity in adrenomedullary chromaffin cells: Role of Opioid receptor stimulation. Shaima Salman, Josef Buttigieg, Colin A. Nurse * Department of Biology, McMaster University, Hamilton, Ont., Canada L8S 4K1 Prior to preganglionic innervation, neonatal adrenomedullary chromaffin cells (AMCs) respond directly to hypoxia by evoking catecholamine (CAT) secretion. CAT secretion is a crucial physiological response during the transition of newborns from an intrauterine to extrauterine environment. This non-neurogenic response to hypoxia is suppressed postnataly along a time course that parallels the development of splanchnic innervation. Opioid peptides are released from the nerve terminals of the splanchnic nerve and together with acetylcholine (ACh) have been proposed to play a role in the suppression of the direct hypoxic response of AMCs. Recent studies from our lab suggest that chronic opioid receptor stimulation in vitro causes a loss of hypoxic sensitivity in primary neonatal AMCs. In this study, we examine the molecular mechanisms by which chronic opioid receptor stimulation leads to the loss of hypoxic sensitivity using a surrogate immortalized chromaffin cell line (MAH cells). Similar to neonatal AMCs, hypoxia causes inhibition of oxygen-sensitive K+ channels leading to membrane depolarization, activation of voltage-gated Ca2+ channels, and CAT secretion in MAH cells. In addition, ATP-sensitive K+ channels (KATP) are activated during hypoxia resulting in hyperpolarization and regulation of CAT secretion. Real time-PCR and western blot analysis indicated that exposure of MAH cells to '- and )-opioid receptor agonists for ~7 days in culture resulted in selective up-regulation of KATP channels. In addition, there was an up-regulation in cystathionine beta synthase (CBS), an enzyme responsible for the production of hydrogen sulfide (H2S). H2S has recently been proposed as a signaling gasotransmitter involved in O2sensing in certain cell types. Interestingly, accumulating evidence points to the KATP channel as a target of H2S causing its activation. These data suggest that the up-regulation of KATP channels and their possible activation by endogenous H2S production during chronic opioid receptor stimulation may contribute to the suppression of the hypoxic response in AMCs after splanchnic innervation.
POSTER #80 Role of Class I Immune Molecules in mediating Sickness Behaviour Ashwin Sankar, Robyn MacKenzie, Jane A. Foster Department of Psychiatry & Behavioural Neurosciences, McMaster University Brain-Body Institute, St. Josephâ€™s Healthcare, Hamilton, ON, The role for MHC class 1 proteins is growing past the immune realm. In particular, the discovery of MHC I proteins in neurons as cellular indicators of stress potentiates their role as a communicatory molecule between the peripheral immunological mechanisms and the brain. In order to further characterize their role, our group performed behavioural testing on functional class I MHC knockout mice (constitutive "2-microglobulin (B2M) and transporter associated with antigen processing (TAP) double knockouts). Specifically, we quantified their basal locomotor and elevated-plus maze activity, as well as sickness behaviour following injection with endotoxin (LPS); this was compared with generic C57BL/6 (B6) mice. Our experiments testing basal behaviour yielded significant differences in locomotor activity between female B2M-/-/TAP-/- and B6 mice, and in time spent in the open intersection area of the male groups. When sickness behaviour was characterized, more differences emerged: locomotor activity was attenuated beyond 15 minutes in male B6 mice receiving LPS, though no similar effect emerged in B2M-//TAP-/-mice; similarly in females, while the LPS effect emerged beyond 25 minutes in B6 mice, no such effect emerged in the female B2M-/-/TAP-/-group. The results of our experiment point to aberrant signalling of the immune stress signal in the B2M-/-/TAP-/- group, and will open doors to elucidating the pathway via which the brain communicates with such peripheral machinery as the immune system.
POSTER #81 Prenatal programming by excess testosterone of appetite regulatory peptides in the arcuate nucleus of the female sheep Kayla M. Sheppard, MSc Student, Department of Anatomy and Cell Biology, The University of Western Ontario; Lique M. Coolen, PhD, Department of Anatomy and Cell Biology, The University of Western Ontario; Guanliang Cheng, MD, Department of Anatomy and Cell Biology, The University of Western Ontario; Vasantha Padmanabhan, PhD, Department of Pediatrics, Obstetrics and Gynecology, and Molecular and Integrative Physiology, University of Michigan; Michael N. Lehman, PhD, Department of Anatomy and Cell Biology, The University of Western Ontario Changes in the in utero environment of the fetus reprogram its growth and developmental trajectory. In utero exposure to excess testosterone (T) produces both reproductive and metabolic dysfunction in females. In particular, ewes treated prenatally with T, display metabolic deficits, including insulin resistance and hyperinsulinema. We hypothesize that prenatal T excess leads to changes in appetite regulatory peptides of the hypothalamic arcuate nucleus, and that these changes may in part be responsible for the metabolic deficits seen in these animals. We focused on two populations of arcuate neurons important for the regulation of appetite and energy balance: agouti-related peptide (AgRP) and pro-opiomelanocortin (POMC) neurons. Specifically, we compared the number of AgRP- and POMC- immunoreactive neurons in rostral, middle and caudal levels of the arcuate nucleus between obese (n=6, mean body weight 115.3 ± 4.3 kg) and normal weight (n=5, mean body weight 89.6 ± 3.2 kg) adult ewes, and between normal weight prenatal T-treated (n=5) and untreated females (n=5). Prenatal T ewes were exposed to excess T in utero between days 30-90 of the 147 day gestational period. Obese ewes had 40% fewer AgRP expressing neurons in middle and caudal levels of the arcuate nucleus compared with normal weight controls, and 60% more POMC expressing neurons than normal weight ewes in the rostral division of the nucleus. This suggests a potential compensatory mechanism within the obese brain to diminish food intake and lower body weight. By contrast, prenatal T ewes had more than twice the number of AgRP neurons (251.0 ± 17.0) in the middle arcuate nucleus compared to controls (107.6 ± 15.1), suggesting that prenatal T treatment alters the metabolic circuitry within the hypothalamus in the absence of changes in body weight. No difference was found in the number of POMC expressing neurons between prenatal T ewes and controls. These results suggest that the increased number of AgRP cells in the prenatal T animals may be a factor contributing to metabolic dysfunction in these animals, given its role as an appetite stimulatory peptide. Further, the findings may be of translational relevance to increased risk of obesity and type II diabetes in polycystic ovarian syndrome, the characteristics of which are mimicked by prenatal T-treated sheep. Supported by NIH Grants R01 HD041098 to VP, and P01 HD044232 to VP and MNL
POSTER #82 SIRT3 OVEREXPRESSION PROTECTS DIFFERENTIATED PC12 CELLS FROM GLUCOSE DEPRIVATION OR OXYGEN-GLUCOSE DEPRIVATION. Natalya Shulyakova, PhD Student, Department of Physiology, University of Toronto; James H. Eubanks, PhD, University of Toronto, and Linda R. Mills, PhD, University of Toronto. SIRT3 is a mammalian sirtuin targeted to mitochondria. In non-neuronal cells SIRT3 overexpression increases cellular respiration efficiency, and decreases levels of reactive oxygen species. SIRT3 is present in the brain but there is little data on SIRT3 in neurons. We hypothesized that over-expression of SIRT3 would be neuroprotective and diminish cell vulnerability to oxidative stress. Differentiated PC12 cells were transfected with pTracer-CMV2SIRT3 plasmid; transfection efficiency was 43.4 ± 2.7% after 24h. MTT reduction assays showed that cell viability was decreased for the first 4 days post-transfection but subsequently recovered. Confocal imaging using Rhodamine123 revealed that mitochondrial membrane potential was decreased in SIRT3 overexpressing cells but mitochondrial morphology was normal. PC12 cells were challenged with glucose deprivation (GD) or oxygen-glucose deprivation (OGD). GD was induced by incubating cells for 4 hours in glucose/glutamine deficient medium (-/- medium) plus 10mM 2deoxy-D-glucose (2DG) and 10µM CCCP. To induce OGD cells were incubated with (-/-) medium plus 2DG, and placed in an anoxic environment for 5 hours. Cell death was quantified using confocal microscopy and PI as follows: % of dead transfected cells = (# of dead (PI+) transfected cells/ # of transfected cells) x 100%. SIRT3 overexpression was neuroprotective for GD; after a GD challenge followed by 15 hrs reperfusion (RP), cell death was 39.7 ± 9.3 % in SIRT-3 overexpressing cells versus 72.5 ± 9 % in controls transfected with plckGFP. SIRT3 overexpression also reduced cell death after OGD; 20 hrs post OGD/RP cell death in SIRT3 transfected cells was significantly less (10.4±5.1%) than in controls transfected with plckGFP (32.0 ±11.7%). These data are the first evidence that SIRT3 over-expression is protective in a neuronal model of oxidative stress.
POSTER #83 The molecular signature of anxiety-like behaviour in mice exposed to a postnatal immune challenge Michelle M. Sidor1,3, Glenda MacQueen2,3 & Jane A. Foster1,3 Department of Psychiatry and Behavioural Neurosciences, McMaster University1, Department of Psychiatry, University of Calgary2 and the Brain-Body Institute, St. Josephâ€™s Healthcare3 The development of stress-reactivity and emotionality has been shown by both clinical and preclinical work to be influenced by the early immune environment. Immune challenge with lipopolysaccharide (LPS) during the first postnatal week in rodents leads to long-term alterations in anxiety-like behaviour. Given that indicators of anxiety often present during adolescence in the clinical population, our work focused on identifying molecular alterations across development that may contribute to the early emergence of anxiety. In particular we examined neuroplasticity-related substrates, including BDNF and serotonergic gene expression, as well as hippocampal neurogenesis. Mice were administered LPS (0.05mg/kg, i.p.) on postnatal days 3 and 5. Gene expression was examined in parallel with assessment of exploratory and anxietylike behaviours during development. Adult hippocampal neurogenesis was assessed by immunoreactivity for BrdU and doublecortin. Molecular analysis revealed an altered spatiotemporal profile of BDNF and serotonergic gene expression in LPS-mice during the developmental time period in which anxiety emerges. This was concurrent with reduced exploratory behaviour in male LPS-mice and increased anxiety-like behaviour in female LPSmice; both of which persisted into adulthood. Female LPS-mice also exhibited altered adult hippocampal neurogenesis which may be linked to this anxiety-like phenotype. The present study reveals nuances in the developmental nature of anxiety and suggests that altered neuroplasticity-related gene expression and hippocampal neurogenesis may contribute to anxiety-like behaviours. Elucidating the molecular substrates contributing to anxiety provides insight into the differing susceptibility of the developing CNS to early immune challenge and the possible contribution of these alterations to behavioural dysfunction.
POSTER #84 SIRTUINS 1 AND 3 ARE EXPRESSED THROUGHOUT DEVELOPMENT IN CENTRAL NERVOUS SYSTEM, AND THEIR LEVELS DECREASE WITH AGE. Elena Sidorova, M. Sc. Student, Graduate Studies in Physiology; Dorotea Mutabdzic, MD Student; James Eubanks PhD, Division of Genetics and Development, University of Toronto Despite substantial research towards understanding age-related decline, researchers are still looking for solutions that will defy or at least slow the inevitable. â€œAgingâ€? is associated with an overall reduction of metabolic efficiency, a decrease in ATP synthesis, and the increased genesis of reactive oxygen species (ROS). In turn, these correlate with a greater risk of neurodegenerative conditions, and more severe damage from traumatic insults. Declining mitochondrial function has for decades been hypothesized to contribute significantly to agerelated decline, but the mechanisms responsible for this decline remain unclear. Recent studies have identified a family of enzymes known as sirtuins (SIRT1-7) whose activity has been demonstrated to either directly or indirectly influence longevity, with SIRT1 and SIRT3 being shown to improve the fidelity of mitochondrial function. While several studies have examined the role of SIRT1 in longevity enhancement and as a neuroprotective factor, the role of SIRT3 remains relatively uninvestigated. To begin addressing whether SIRT1 and SIRT3 play roles in age-related neural mitochondrial decline, I compared the expression levels of the two in the brain throughout development using quantitative real time PCR. My results show that SIRT3 and SIRT1 mRNA levels are robustly expressed in different brain regions including hippocampus, cortex, striatum, and cerebellum throughout development, with SIRT3 being expressed at significantly higher levels in each brain region. In the aged cortex and hippocampus, however, the mRNA levels of both SIRT1 and SIRT3 are significantly decreased compared to their levels in young mice. As the function of both SIRT1 and SIRT3 stabilizes mitochondrial efficiency, these results suggest that the observed age-related decline in mitochondrial efficiency could arise from diminished levels of SIRT1 and SIRT3.
POSTER #85 Investigating the changes in Bcl2 and Bcl11b expression in the lymphocytes of individuals with schizophrenia Christal Sookram, M.Sc. Student, Graduate studies in Neuroscience MiNDS, McMaster University; Nancy Thomas, M.Sc., Department of Psychiatry and Behavioural Neurosciences, McMaster University; Dipa Basu, PhD Student, Graduate studies in Health Science, McMaster University; Ram K Mishra, PhD, Department of Psychiatry and Behavioural Neurosciences, McMaster University Molecular markers for disease are essential to facilitate effective diagnosis. In a microarray investigation, performed by Scherzer et al. (2007), they found that B-cell CLL/lymphoma 2 (Bcl2) and B-cell CLL/lymphoma 11B (Bcl11b) are altered in their expression in the blood of Parkinson’s patients. However, it is not yet known whether this change in the expression of Bcl2 and Bcl11b is unique to the Parkinson’s disease patient. The aim of this study is to expand our understanding of the efficiency of these two molecules in accurately distinguishing Parkinson’s disease from schizophrenia using a blood sample. Furthermore, we hope to clarify whether these molecules might play some role in the schizophrenic state. Bcl2 specifically was found to be down-regulated in the cortex of schizophrenic patients (Jarskog et al. 2000). Thus, it is possible that this down-regulation in the CNS might be reflected in the blood of schizophrenic patients. Bcl11b is a Kruppel- like zinc finger protein that is thought to play some role in T-cell maturation and the prevention of apoptosis in tumor cells (Grabarczyk et al. 2007). However, little is known about Bcl11b and its possible relation to the neuropsychiatric disorders of Parkinson’s disease and schizophrenia. Real time PCR and semi-quantitative PCR were used to analyze changes in the expression of these two molecules in the lymphocytes of schizophrenic patients verses controls. No change was seen in the expression of Bcl11b in schizophrenic patients, suggesting that perhaps this molecule might be effective in distinguishing Parkinson’s disease from schizophrenia. However, preliminary data suggests that the Bcl2 expression was decreased in the schizophrenic patients relative to controls. While this result does not permit the use of Bcl2 as a molecular marker of Parkinson’s disease, it does raise the question of what role this molecule might play in schizophrenia. Perhaps, a down-regulation of this molecule in the blood reflects and generally greater susceptibility of schizophrenic patients to apoptotic cell death. Further investigation is essential, but it is very likely that both of these molecules have key roles to play in our future understanding of schizophrenia and Parkinson’s disease. References Grabarczyk P, Przybylski GK, Depke M, Volker U, Bahr J, Assmus K, Broker BM, Walther R, Schmidt CA (2007) Inhibition of BCL11B expression leads to apoptosis of malignant but not normal mature T cells. Oncogene 26:3797-3810. Jarskog LF, Gilmore JH, Selinger ES, Lieberman JA (2000) Cortical Bcl2 protein expression and apoptotic regulation in schizophrenia. Biol Psychiatry 48:641-650. Scherzer CR, Eklund AC, Morse LJ, Liao Z, Locascio JJ, Fefer D, Schwarzschild MA, Schlossmacher MG, Hauser MA, Vance JM, Sudarsky LR, Standaert DG, Growdon JH, Jensen RV, Gullans SR (2007) Molecular markers of early parkinson's disease based on gene expression in blood. Proc Natl Acad Sci U S A 104:955-960.
POSTER #86 Detection of crayfish urine using fluorimetry Kristin Spong, H BSc Student, Brock University; A. Joffre Mercier, PhD, Professor, Brock University Tactile, visual and chemical information all provide input to crayfish during agonistic interactions. Urine has been shown to act as a chemical signal between fighting crayfish by injecting fluorescein dye into crayfish in order to visualize and photograph urine release. The present study developed a new method for quantifying urine output, in which fluorescein is injected into crayfish, the amount of fluorescein excreted is quantified using fluorimetry. The method is sensitive enough to detect the urine output reliably from two crayfish in 1500 ml of water. Fluorescence measurements are not influenced by the presence of other substances in the urine. We also investigated the possibility that crayfish may rely more on chemical information when they are fighting in the absence of vision than when vision is available. To address this question, interactions between paired Procambarus clarkii were compared between sighted crayfish and two blindfolded crayfish. Blindfolded crayfish pairs did not release significantly more urine than sighted crayfish pairs. This suggests that crayfish do not rely on chemical information more when fighting in the absence of vision. Supported by NSERC.
POSTER #87 ACTIVATION OF THE MAP KINASE SIGNALING PATHWAY AND GLUTAMATE RECEPTORS IN LUMBAR SPINOTHALAMIC CELLS WITH EJACULATION Michael D. Staudt, M.Sc. Student; Cleusa V.R. de Oliveira, Ph.D.; Lique M. Coolen, Ph.D., Department of Anatomy & Cell Biology, University of Western Ontario Ejaculatory reflexes are controlled by a spinal generator in the lumbosacral spinal cord, consisting of lumbar spinothalamic (LSt) cells. LSt cells are activated with ejaculation and LSt lesions ablate ejaculation. However, the nature of the signal transduction pathways and neurotransmitters involved in the activation of LSt cells is unknown. We hypothesize that LSt cells are activated with ejaculation via glutamatergic input and MAP kinase signaling. This hypothesis was tested using both behavioral and physiological paradigms. In the behavioral paradigm, male rats were allowed to display either mounts, mounts and intromissions, or one ejaculation, and were sacrificed 5 or 30 minutes later. Control males did not mate. Spinal cord tissue was immunoprocessed for phosphorylated NMDA receptor subunit 1 (pNR1; 30 minute groups) or phosphorylated MAP kinase (pERK; 5 minute groups) and galanin (LSt marker). LSt cells were analyzed for expression of pNR1 or pERK, and data are expressed as the mean percentages of LSt cells that express phosphorylated immunoreactivity. Induction of pNR1 in LSt cells was significant only with ejaculation (70% of LSt cells), whereas pERK was significantly induced by intromissions (45%) and further increased with ejaculation (90%) relative to controls. In the physiological paradigm, spinal cords of male rats were transected at the mid-thoracic level and dorsal penile nerve (DPN) was electrically stimulated. This stimulation resulted in a bursting response of the bulbocavernosus muscle that is similar to that observed during normal ejaculation. Animals were perfused 5, 10, 15, 30 or 60 minutes following stimulation or control sham procedures and spinal cords were immunoprocessed for pNR1 or pERK and galanin. Expression of pERK in LSt cells was significantly increased 5, 10, and 15 (40 to 70%), but not 30 minutes following DPN stimulation. Expression of pNR1 in LSt cells was significantly increased 5, 15, 30, and 60 minutes (80 to 100%) following stimulation. Controls had negligible pERK or pNR1 expression, thus ERK and NR1 activation was specific for DPN electrical stimulation resulting in ejaculation. In spinal-transected animals, an intrathecal or intraspinal infusion of MEK inhibitor (U0126), or an intraspinal infusion of NMDA receptor competitive antagonist (APV) regionally specific for the LSt cell population was found to inhibit the ejaculatory reflex elicited by DPN stimulation. These results demonstrate that DPN stimulation activates the MAP kinase signaling pathway and glutamate receptors in LSt cells, and pharmacological blockade of these signaling pathways and receptors is sufficient to block the ejaculatory reflex. We therefore hypothesize that activation of these signaling pathways is essential for triggering ejaculation.
POSTER #88 Effects of testosterone on agonistic behaviour in crayfish. Zoltan Torontali, H BSc Student, Brock University; A. Joffre Mercier, PhD, Professor, Brock University Aggression has been a widely studied personality trait. Aggressive behaviour has been studied in a large variety of animal species, including crayfish, which develop a rank of either subordinate or dominant when paired together and allowed to fight. Previous research has shown that injections of serotonin into the subordinate will decrease its willingness to retreat from an encounter with the dominant. Testosterone has been linked to increase aggression in many vertebrate species and has been isolated and detected in the crayfish Astacus Leptodactylus, but there is no research on effects of testosterone on aggression in crayfish. We hypothesized that testosterone injection into subordinate crayfish would increase aggressive behaviours. Testosterone (in 0.1% DMSO) was injected into the pericardial sinus of Procambarus clarkii at a dose of 0.05 mg/kg body weight, and 15 min later agonistic interactions were filmed over a 30 min period. (In control trials, subordinates were injected with 0.1% DMSO). Under these conditions, testosterone did not increase the frequency of aggressive behaviours (approach, initiate, chelae grasp, chelae strike, pull, flip opponent or push) in subordinate crayfish, compared to DMSO trials. However, testosterone did alter some interactions between the subordinate and dominant crayfish, as indicated by differences with DMSO trials and with behaviour observed on the day before injections. Specifically, subordinate crayfish no longer retreated more frequently than dominants, and dominant crayfish no longer initiated more contact or exhibited more chelae grasping than subordinates. These results suggest that testosterone may play a role in aggression in crayfish. Supported by NSERC.
POSTER #89 TD learning versus motivational salience accounts of dopamine in animal models of OCD Trent Toulouse, PhD Student, Graduate Studies in Psychology Neuroscience and Behaviour; Henry Szechtman, Ph.D professor Psychiatry & Behavioural Neurosciences; and Sue Becker Ph.D professor Psychology Neuroscience and Behaviour Disruption of the dopaminergic (DA) system is linked to a wide range of neurological disorders including attention deficit disorder, obsessive compulsive disorder (OCD), schizophrenia and Parkinsonâ€™s disease. An influential contribution to understanding this system has been from reinforcement learning theory, using the temporal-diference (TD) learning algorithm to model the correlation between dopamine cell firing rates in the dorsal striatum and reward prediction errors in associative learning. The TD model, in its simplest form, views the DA signal as conveying the difference between an expected reward and an actual reward. Another influential theory is that DA signals surprise and motivational salience and predicts an increase in firing rates in response to improbable events . To further differentiate between these two formulations of the DA signal we looked at an animal model for OCD. Rats injected with Quinpirole, a dopamine D2/D3 receptor agonist, exhibit compulsive checking behaviour . The injection results in a hyperactivation of the DA signal. We modeled this compulsive checking behaviour using both the TD and the surprise/salience model of the DA signal. In the TD model the compulsive checking behaviour is reinforced because the reward prediction error signal is misreporting the behaviour as increasingly rewarding. In the salience/surprise model the compulsive checking behaviour is induced when the animal perceives something improbable happening during normal activity, and is continued until no unexpected consequence is experienced. Under Quinpirole, the DA signal is constantly reporting that improbable events are occurring so the checking behaviour is never turned off. We found that both models showed similar compulsive checking with hyperactivation of the DA signal, but differed significantly after the hyperactivation was turned off. When the DA signal was not hyperactivated the TD model learned gradually over time that the checking behaviour was no longer rewarding. The checking behaviour was performed frequently at first but over time it significantly decreased. In the salience/surprise model the checking behaviour ceased as soon as the hyperactivated DA signal was turned off, since performance of the checking behaviour was no longer eliciting a surprise signal. We then compared the results of the two models to a preliminary analysis of the behaviour of rats, that had received previous injections of Quinpirole, during a trial where no drug was delivered. We found that the frequency of checking behaviour appeared to drop off immediately, and did not show a significant decrease over time. This suggests that the surprise/salience model of DA signal more accurately predicted animal behaviour than the TD model. This evidence that the DA signal might be best modeled as conveying surprise and motivational salience has important implications for our understanding of learning, action choice and how disruptions in the dopaminergic system contribute to neurological disorders. Toulouse, T. and Becker S. (2008). Why does sensitivity to reward devaluation disappear over learning? A single system Bayesian account (COSYNE), Salt Lake City. Abstract. Szechtman, H., Sulis, W. & Eilam, D. (1998). Quinpirole induces compulsive checking behavior in rats: a potential animal model of obsessive-compulsive disorder (OCD). Behav.Neurosci. 112 (6), 1475-1485.
POSTER #90 Comorbidity of Depressive-Like Behaviour in the Quinpirole Model of Obsessive-Compulsive Disorder Tucci MC1, Graham D3, Jacklin D1, Sharma R2, Greene B2, Al-khatib A2, Kafil T2, Beerepoot P4, Szechtman H5 1
Graduate Student, McMaster Institute for Neuroscience Discovery & Study, 2Undergraduate Student, Bachelor of Health Sciences, McMaster University, 3Research Technician, 4 Undergraduate Student, 5Professor Department of Psychiatry & Behavioural Neuroscience, McMaster University
Depression has been previously identified to be the most prevalent psychiatric disorder found in 54% of individuals with obsessive-compulsive disorder1 (OCD). However does this comorbidity reflect the actual presence of another psychiatric disorder, namely depression? Or is the comorbidity a manifestation of the primary disorder, that being OCD? Empirical evidence has indicated that depression followed the onset of OCD in 65% of individuals. 2 Therefore, it is reasonable to expect that persistent OCD may result in depression. However, such a cause-effect relationship has not been examined in previous studies. As a result, the proposed study will test this hypothesis by examining the comorbidity of depressivelike behaviour using the quinpirole model of OCD in rats. Rats will be administered the D2/D3 dopamine agonist quinpirole according to a standard protocol that has been previously shown to reliably elicit compulsive checking behaviour, providing a reasonable model of OCD. Importantly, two comparison groups will be included. The first group will undergo all experimental phases however only be administered saline, while a second group will be administered quinpirole or saline, but not have the opportunity to develop compulsive checking by remaining in their home cage. This will ensure that the measures obtained reflect the induction of compulsive checking, rather than quinpirole alone. Following the induction of compulsive checking, several approaches will be used to measure depression-like behaviour and assess neurobiological markers of depression. Behavioural measures will include the forced swim test, commonly used to measure antidepressant and pro-depressant effects in animal models of depression. Additionally, a sucroseintake test will be employed to measure responsiveness to a hedonic stimulus as it relates to anhedonia in depression. The body-weight of rats will also be monitored and evaluated as changes commonly occur in depression. Furthermore, anxiety will be measured using the elevated plus maze. Finally, brain-derived neurotrophic factor (BDNF) will be assessed given that changes in BDNF may be produced by events that provoke depression. Preliminary results will be presented. Taken together, the results of the proposed study have several important implications. Foremost, the quinpirole model of OCD may be strengthened by showing another characteristic of the disorder in humans, that being comorbidity. Additionally, a better understanding of the relationship between the onset of depression and the primary disorder may be revealed. This in turn may lead to future studies examining the most effective way to treat comorbidity in individuals with OCD.
Nestadt G, Samuels J, Riddle MA, Liang KY, Bienvenu OJ, Hoehn-Saric R, Grados M, Cullen B. (2001). The relationship between obsessive-compulsive disorder and anxiety and affective disorders: Results from the Johns Hopkins OCD Family Study. Psychological Medicine, 31, 481-487. 2 Riccardi JN, McNally RJ. (1995) Depressed mood is related to obsessions but not compulsions in obsessive-compulsive disorder. Journal of Anxiety Disorders, 9, 249-256.
Nausea-inducing and Antidepressant Effects of Paroxetine on Rats Katharine J. Tuerke, Cheryl L. Limebeer, Francesco Leri, Linda A. Parker University of Guelph, Guelph ON, Canada Katharine J. Tuerke, PhD Student, Graduate Studies in Psychology + Neuroscience Cheryl L. Limebeer, Senior Research Assistant in Psychology Francesco Leri, Associate Professor, Department of Psychology Linda A. Parker, Professor, Department of Psychology Although rats do not vomit, they display conditioned gaping reactions when re-exposed to a flavor previously paired with a nauseating treatment. Paroxetine (Paxil) is the most potent Serotonin Selective Reuptake Inhibitor (SSRI) prescribed to treat depression; however, it produces the unpleasant side effect of nausea. To investigate paroxetineâ€™s ability to produce conditioned gaping rats were intraorally infused with 17% sucrose solution for four conditioning/testing trials and immediately injected (i.p.) with one of following dosages of paroxetine (0, 3, 10 and 30 mg/kg). During the trials the ratsâ€™ disgust reactions were recorded. The 30 mg/kg dose of paroxetine produced conditioned gaping after 3 conditioning trials, indicating that the highest dose produced nausea. A second experiment investigated whether the same doses of paroxetine that produced nausea were also effective antidepressants using the forced swim test (FST). On the first day of testing rats were exposed to a 15 min swim test and 24 h later to a 5 min swim test. The rats were injected with one of the same doses of paroxetine used during conditioning on each of three occasions (23.5, 5 and 1 h) prior to the 5 min swim test. Paroxetine dose-dependently increased swimming and decreased immobility compared to vehicle treated rats. These results indicate that paroxetine produced an antidepressant effect at a lower dose than that necessary to produce nausea. The taste reactivity test can be used as a nausea prescreening tool for new pharmacological treatments.
POSTER #92 Development of an fMRI Temperature-Sensitive Protocol for Chemotherapy-Induced Peripheral Neuropathy Oi Lei Wong, MSc. student1,2, Raimond Wong, MD3, Michael D. Noseworthy, PhD1,2,4 Brain Body institute, St. Joseph's Healthcare, Hamilton, Ontario, 2Department of Medical Physics and applied radiation science, McMaster University, Hamilton Ontario, 3Department of Oncology, Juravinski Cancer Centre, and 4Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario. 1
The blood brain barrier (BBB) is expected to protect the brain from potential damages caused by chemotherapy drugs. However, side effects of chemotherapy, such as memory loss and changes in cognitive function, are observed. For example, chemotherapy can result in heightened sensitivity to increased temperature. To test this side effect we proposed and developed a novel fMRI protocol for brain mapping using four temperature stimulation levels; 12oC, 21oC, 35oC and 40oC. Using this approach we hypothesized post-chemotherapy patients would have temperature induced pain activation while healthy controls would only show sensory changes. Using a 3T MRI system and 8 channel receive-only head coil, blood oxygen level dependant (BOLD) signal change between temperature states were compared using a general linear model (GLM). stimulation
s rest state
To date we have tested this approach on healthy volunteers who have showed expected re sensory cortex state activation. A repeatability test has been conducted and has shown excellent results (figure 1). We are now recruiting state chemotherapy patients. When comparing the result between healthy group and chemotherapy patients, larger BOLD signal is expected from hypersensitive chemotherapy patients. The effect of each temperature level will be analysed using multiple regression analysis. These results will be compared to locate the temperature induced pain threshold in individual chemotherapy patients.
Figure 1: F test map from the multiple regression analysis of the same subject imaged on three different dates. (threshold at p = 4.4e-4, F = *)5.19
POSTER #93 What drives tactile spatial acuity enhancement in the blind: tactile experience or visual deprivation? Contributing Authors: Michael Wong, PhD Student, Graduate Studies in Neuroscience; Daniel Goldreich, PhD, McMaster University (1) Introduction & Purpose: Tactile spatial acuity is reportedly enhanced in the blind, but the factors that cause this enhancement are unknown. Does increased reliance on the tactile sense (tactile experience hypothesis) or the absence of vision (visual deprivation hypothesis) lead to tactile acuity enhancement? Tactile experience may cause the enlargement of somatosensory cortical representations (somatosensory plasticity), and the absence of vision may cause recruitment of occipital cortical areas for tactile tasks (crossmodal plasticity). Our goal here was to test whether tactile experience and/or visual deprivation drive tactile acuity enhancement. (2) Materials and Methods: We used a two-interval forced choice grating orientation task to assess the passive tactile spatial acuity of blind and sighted subjects on the fingertips and lips. To assess the tactile experience hypothesis, we tested multiple fingers to determine whether fingers that are used more frequently (e.g., for Braille reading) outperform fingers that are used less frequently. To assess the visual deprivation hypothesis, we tested the lips. Since tactile experience on the lips is presumably similar in the two groups, better performance on the lips by blind subjects would suggest that visual deprivation is driving tactile acuity enhancement. (3) Results: We found that blind subjects outperformed sighted subjects on all of the tested fingertips and on the lips. Among the blind subjects, those who read Braille outperformed those who did not read Braille. Among proficient Braille readers, the preferred reading index finger outperformed the other index finger. We also found that proficient Braille readers who read more, and consequently received more tactile experience on the preferred reading index finger, performed better on that finger. (4) Conclusion: Our results demonstrate that blind subjects better resolve spatial details with the fingertips and lips than sighted subjects. The effect of Braille reading on the fingers suggests that tactile experience drives tactile acuity enhancement. The better performance of blind subjects than sighted subjects on the lips, suggests additionally that the absence of vision drives tactile acuity enhancement. These results may reflect a role for both somatosensory and crossmodal plasticity in tactile acuity enhancement in the blind.
POSTER #94 MBD2, ANOTHER METHYL-CPG-BINDING PROTEIN, CONTRIBUTES TO AUTISM-LIKE BEHAVIOURAL PHENOTYPE IN MICE Zavalishina L. 1, 2 *, Safir A.2, Yonekura1 N. , Logan R. 1, Zhang L.1, 3, Eubanks J. 1,2,3.Division of Genetics and Development 1, Toronto Western Research Institute, Toronto, Ontario, M5T 2S8, Canada. Department of Physiology 2, Institute of Medical Science, Surgery, Faculty of Medicine, University of Toronto 3, 1 Kingâ€™s College Circle, Toronto, Ontario, Canada. The importance of epigenetic influence in variety of diseases and behaviors is becoming increasingly clear. Methyl-CpG- binding proteins (MBP) such as MeCP2, MBD1-MBD3, recruit transcriptional co-repressor molecules to methylated regions of the genome which modify surrounding chromatin and generally silence transcription. It is now clear that these factors participate in neural development and functional maintenance, as mutations in MeCP2 cause the autism spectrum disorder of Rett syndrome, the deficiency of MBD1 in mice leads to autismlike behavioural deficits, and early embryonic neural development is aberrant in mice lacking MBD3. To date, however, the role of MBD2 in regulating brain function and behaviour remains largely unexamined. To begin elucidating whether and how MBD2 influences neural function, I compared the performance MBD2-null mice to wild-type mice in a battery of behavioral tests, and compared their somatosensory and hippocampal electroencephalographic (EEG) activity in vivo during exploration, sleep and immobile states, and the magnitude of hippocampal synaptic plasticity in vitro. The results of these assays indicate that MBD2-null mice display a heightened anxiety-like behavior, diminished explorative activity, and progressively decreased activity levels compared to wild-type mice. However, these behavioral differences were not paralleled by neurophysiological impairments, as long-term potentiation at MBD2-null CA1 synapses was preserved, and analysis of the EEG patterns of MBD2-null mice failed to identify significant differences from wild-type mice. Specifically, MBD2 null mice display normal low amplitude desynchronized basal activity in hippocampus, clear theta activity of normal frequency during exploration, the lack of abnormal slow spike and wave discharges during immobile and sleep stages, and preserved delta-like activity and sharp waves during sleep in cortex and hippocampus, respectively. Taken together, these data indicate that the loss of MBD2 is sufficient to induce a state of heightened anxiety-like behavior in mice without introducing gross deficits in hippocampal or cortical neurophysiology.
POSTER #95 Neural projection from area 5 to primary motor cortex in healthy adults: a TMS study Angela Ziluk, M.Sc. Student, Graduate Studies in Kinesiology; Aimee J. Nelson, PhD, University of Waterloo Manual behaviours such as manipulation of tools and other small objects requires a high level of dexterity, an evolutionary skill acquired by humans and few nonhuman primates. Such activities are dependent on the integrity of somatosensory input arising from the thumb and digits. Research conducted in Old World monkeys has identified Brodmannâ€™s area 5 (BA 5) as an important cortical structure that appears to have evolved with the ability to perform skilled hand movements. In addition to processing somatosensory input, BA 5 has direct projections to primary motor cortex (M1), and thus may influence motor output of the hand. Little is known about human BA 5. The purpose of this experiment was to characterize the nature (excitatory versus inhibitory) and timing of the projection from BA 5 to M1 in healthy adults during rest and processing of somatosensory input using paired-pulse transcranial magnetic stimulation (TMS). Twelve (right-handed) healthy volunteers (five male and seven female, 22-36 years old) participated in the experiment. Transcranial Magnetic Stimulation (TMS) was performed at the University of Waterloo using BiStim-2/Magstim 2002 stimulators with two customized 50 mm branding coils. One coil was positioned over BA 5 and the other over M1. Accurate placement of the M1 coil elicited a motor evoked potential (MEP) recorded in the first dorsal interosseous (FDI) muscle of the right hand. The participant was aligned with their MRI using Brainsight Neuronavigation system. Paired-pulse TMS was performed whereby a conditioning stimulus (CS) at an intensity of 90% of resting motor threshold was delivered to BA 5 and the subsequent test stimulus (TS) was delivered to the first dorsal interosseous (FDI) hotspot within M1 at an intensity necessary to evoke an MEP of ~ 1 mV. The interval between the CS and TS was tested at the following interstimulus intervals; 6,8,10,12,30,40 and 50 ms. The dependent variable was the MEP amplitude in the FDI muscle during the conditioned state normalized to the unconditioned state (TS alone). The neural projection from BA 5 to M1 was recorded during 1) rest with both hands completely relaxed, 2) during vibrotactile stimulation at 23 Hz to the fingertips of digits 1 and 2, 3) during vibration at 80 Hz to the FDI tendon and opponens pollicis tendon and 4) during simultaneous vibration to the tips of digits 1 and 2 and their corresponding tendons. All stimulus conditions were delivered to the right hand. In each of the 4 conditions the CS-TS pair was delivered over the left hemisphere. It was specifically hypothesized that vibration applied to the digits, tendons and their combination will alter the neural interaction, such that the amplitude of the MEP will be facilitated. Preliminary analysis on the data suggested that an early facilitation was present during rest condition (10 and 12ms), during digit stimulation (6 and 10ms) as well as in the combination of digit and tendon vibration (8 and 12ms). Facilitation was also seen at later latencies, specifically for the tendon stimulation condition (30ms) and the combination of stimulation condition (30 and 40ms). Early facilitory effects may reflect corticocortical projections from area 5 to frontal areas of the cortex via the superior longitudinal fasiculus. The information obtained from these experiments will provide novel neuroscience insight by probing paths that have not previously been tested in humans, and provide insight for clinical studies aiming to alter cortical excitability along the somatosensory-motor path.
POSTER #96 Effects of noise on the auditory sensitivity in a hearing generalist, the round goby, Neogobius melanostomus !
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Department of Biological Sciences, University of Windsor 401 Sunset Ave., Windsor, ON N9B 3P4 Canada
Abstract: As underwater environments are increasingly disturbed by various anthropogenic noise sources (i.e. boat engines, seismic surveys etc.), it becomes critical to understand the effects of such noise on the auditory capacity of organisms. Teleost fishes represent an ideal group to investigate these issues, as they entail tremendous diversity in their hearing capabilities. Although a few studies have already concluded that fishes are not equally affected by noise, few reveal its direct impact on the physiology of the auditory system. This study is among the first to address such concerns. The main objective of the current study was to assess the immediate effects of natural background noise exposure (at levels of 135, 150 and 162dB re: 1'Pa) and white noise exposure (at 150, 162 and 170dB re: 1'Pa) on the auditory sensitivity of a hearing generalist, the round goby, Neogobius melanostomus. The round goby represents a suitable model organism for answering the central question of this study because it demonstrates extensive distribution across various aquatic habitats, exposing it to an array of acoustic environments. Use of white noise as a test condition enabled a more realistic view of the effects of noise exposure over a wider range of frequencies. Two signal types were used to evaluate the extent of noise masking: an artificially generated tone burst sound, and a conspecific call. Detection of tone burst was assessed at frequencies ranging from 100Hz to 300Hz, as this range was previously shown to be the most sensitive within the acoustic repertoirse of the round goby. Auditory brainstem response (ABR) technique was employed for quick measurement of the hearing thresholds. Background noise (162dB re: 1 'Pa) and white noise (162dB re: 1 'Pa) exposure caused an increase in auditory thresholds of 23dB and 16dB, respectively. Moreover, white noise (170dB re: 1 'Pa) exposure resulted in complete masking of tone burst sound detection, and only a 5dB elevation in the auditory thresholds analyzed in response to a conspecific call. The 5dB increase in detection of a round goby call was consistent with both background noise (162dB re: 1 'Pa) and white noise (162dB re: 1 'Pa). All the increases in hearing thresholds were highest at 200Hz, establishing this as the frequency most affected by noise within the best hearing range of the round goby. This study highlights how well gobies detect relevant signals in the presence of noise, and facilitates a new avenue to possible control of the rapid migration of this species through acoustic traps.
POSTER #97 CHARACTERIZATION OF RAB3A AND #-SYNUCLEIN INTERACTION AND CONSEQUENCES ON #-SYNUCLEIN COMPARTMENTALIZATION Robert H.C. Chen, MSc. Student, Department of Physiology, University of Toronto, Naomi Visanji, PhD, University of Toronto; M. Stanciu, University of Toronto; Howard T.J. Mount, PhD, Department of Physiology, Institute of Medical Science, University of Toronto; Anurag Tandon, Institute of Medical Science, University of Toronto. The development of intracellular inclusions known as Lewy bodies is a histopathological hallmark of Parkinsonâ€™s disease (PD). The major component of these inclusions is !synuclein, a protein that is predominantly localized to the pre-synaptic terminals of neurons. !-Synuclein appears to alternate between membrane-bound and cytosolic compartments. The dissociation of !-synuclein from vesicles is aided by brain cytosolic proteins that may play a role in the formation of neurotoxic fibrils under pathological conditions of oxidative stress. Previous work from our lab suggests that the small GTPase rab3a is involved in the binding of !-synuclein to synaptic membranes. In this study, we show that rab3a can be co-immunoprecipitated with !-synuclein in synaptosomes generated from murine brains and that this interaction appears to occur preferentially on vesicle membranes. Furthermore, we show that over-expression of the predominately GTP- and membrane-bound Q81L-rab3a mutant in depolarized SHSY5Y human neuroblastoma cells causes a reduction of soluble compartment !synuclein as compared to over-expression of wild-type rab3a. Our findings further the understanding of the dynamics in !-synuclein compartmentalization under nonpathological conditions.
POSTER #98 Diurnal Variation in Reward, Mesolimbic Tyrosine Hydroxylase and Clock Gene Expression in the Male Rat Ricardo M. Baltazar, MSc Student, Ian C. Webb, PhD, Lique M. Coolen, PhD & Michael N. Lehman, PhD. Anatomy and Cell Biology, University of Western Ontario. The impact of the circadian timing system upon behavior and physiology is pervasive and previous evidence suggests a circadian modulation of drug-seeking behaviour and responsiveness to drugs of abuse (Baird & Gauvin, 2000; Abarca et al., 2002). To further characterize daily rhythms in reward and to extend these observations to natural reinforcers, diurnal variation in the rewarding value of sex, palatable food, and systemic amphetamine was assessed via the conditioned place preference paradigm. To identify potential mechanisms for rhythmicity in reward, the expression of tyrosine hydroxylase (TH) and core clock genes (period1 and bmal1) were examined across the day in the ventral tegmental area (VTA) and the nucleus accumbens (NAcc). During an initial training period, male rat sexual performance varied diurnally with a nadir during the light-to-dark transition. Diurnal rhythms also were evident for both sexual and amphetamine-related reward with the variation in sexual reward maintained under constant conditions. However, the rhythms for these particular stimuli exhibited a phase disparity. A diurnal variation also was noted for the locomotor activating effect of acute amphetamine administration. In general, western blotting revealed that TH, Period1, and Bmal1 were rhythmic in the NAcc but did not show robust oscillations in the VTA. Thus, it appears that both natural and drug-related reward vary in a diurnal fashion and that this may be mediated, in part, by rhythmic NAcc dopaminergic activity or clock gene expression. However, as disparate rewards are associated with their own unique rhythms, circadian regulation likely occurs at multiple levels of the mesolimbic reward system.
POSTER #99 Role of Spy1 in neural differentiation. Implications in the development of neurological cancers. Lubanska D1, Market B3 , Chen L2 and Porter LA1. 1 University of Windsor, Windsor, Ontario; 2 National Tsing Hua University, Hsinchu, Taiwan; 3 University of Western Ontario, London, Ontario. Speedy (Spy1) is a protein that enhances cell proliferation by activating the cyclin dependent kinase (CDK) CDK21. This is accomplished, at least in part, by directly promoting the degradation of the kinase inhibitor p27Kip12. Both enhanced CDK2 activity and reduced levels of p27 are implicated in many aggressive forms of cancer. To date, it is known that Spy1 protein levels are elevated in invasive ductal carcinoma of the breast3 and that Spy1 is intimately involved in the initial stages of mammary gland development4. Hence, elucidating the functions of this protein in both normal and aberrant growth conditions is of high priority. Investigation into the spatial and temporal expression of Spy1 in the adult mammalian brain has demonstrated that Spy1 protein levels are elevated in regions known to exhibit continued neurogenesis; the hippocampus and olfactory bulbs. The expression of Spy1 at these regions was found at low levels at early postnatal stages gradually increasing along the developmental time course of the mammalian brain implicating role of Spy1 in adult neurogenesis. To determine the role of Spy1 in neurogenesis the PC12 cell line was used. This cell line can be induced to differentiate through the addition of nerve growth factor (NGF). Experiments studying protein levels of Spy1 throughout a differentiation time course demonstrate that Spy1 levels decrease proportionately with CDK2 kinase activity as differentiation progresses. To further study Spy1 role in neural differentiation, we over expressed Spy1 in SHSY-5Y neuroblastoma cells. The cells were subjected to 13-cis Retinoic Acid over the differentiation time course. We found that Spy1 overexpression prevented differentiation comparing to wild type control cells. Importantly, using a panel of human brain tissues we have found that Spy1 protein and CDK2 kinase activity are elevated and p27 protein levels are downregulated in a number of gliomas compared to pair matched normal controls. Moreover, the analysis of tissue microarrays including multiple brain tumour samples of different types revealed high expression levels of Spy1 in high grade or poorly differentiated glial tumors in comparison to normal adjacent tissues. It is our hypothesis that Spy1 plays a key role in developmental decisions in the brain and that abrogation of this function contributes to various forms of neural derived and brain cancers. Collectively, this project has elucidated a potentially crucial role for the novel cell cycle regulator Spy1 in the regulation of neural cell proliferation and differentiation. Furthermore, we are the first to demonstrate the potential involvement of this protein in the development and/or progression of various brain cancers. 1. Porter, L. A. et al. Human Speedy: a novel cell cycle regulator that enhances proliferation through activation of Cdk2. J Cell Biol 157, 357-66 (2002). 2. Porter, L. A., Kong, M. & Donoghue, D. J. Speedy interacts with p27Kip1 to allow G1/S progression. Mol Biol Cell 14, 3664-3674 (2003).3. Zucchi, I. et al. Gene expression profiles of epithelial cells microscopically isolated from a breastinvasive ductal carcinoma and a nodal metastasis. Proc Natl Acad Sci U S A 101, 18147-52 (2004).4. Golipour, A., Moorehead, R. A., Seegroves, T., Donoghue, D. J. & Porter, L. A. Role of Spy1 in Mammary Gland Development; Implications in the Development of Breast Cancer. Genes and Development (in preparation) (2006).
Department of Psychiatry and Behavioural Neurosciences