Change Marijuana Brain Change in Chronic Marijuana Use: Volume and Connectivity Abnormalities

On November 15, the first study to comprehensively identify existing abnormalities in brain function and structure of long-term marijuana users published on the cover of one of the world’s most-cited and comprehensive multidisciplinary scientific journals, Proceedings of the National Academy of Sciences ( PNAS ). Led by BrainHealth’s Director of the Cognitive Neuroscience Research in Addictive Disorders, Francesca Filbey, Ph.D., the research suggests that the effects of chronic marijuana use on the brain may depend on age of first use and duration of use. Magnetic resonance imaging (MRI) techniques reveal smaller brain volume and increased brain connectivity in the orbitofrontal cortex (OFC), a part of the brain commonly associated with addiction, decision making, inhibition and motivation. The earlier and longer someone uses marijuana, the more pronounced the brain differences.

“The results suggest increases in connectivity, both structural and functional, that may be compensating for gray matter losses,” said Dr. Sina Aslan, founder and president of Advance MRI, LLC and adjunct assistant professor at The University of Texas at Dallas. “Eventually, however, the structural connectivity or ‘wiring’ of the brain starts degrading with prolonged marijuana use.”

“We have seen a steady increase in the incidence of marijuana use since 2007,“ said Dr. Filbey. “However, research on its long-term effects remains scarce despite the changes in legislation surrounding marijuana and the continuing conversation surrounding this relevant public health topic.”

The research team studied 48 adult marijuana users and 62 gender- and agematched non-users, accounting for potential biases such as gender, age and ethnicity. The authors also controlled for tobacco and alcohol use. On average, the marijuana users who participated in the study consumed the drug three times per day.

Cognitive tests show that chronic marijuana users had lower IQ compared to ageand gender-matched controls but the differences do not seem to be related to the brain abnormalities since no direct correlation can be drawn between IQ deficits and OFC volume decrease.

Tests reveal that the most dramatic connectivity increases appear when an individual first starts using marijuana, and the younger the person when he or she first begins using marijuana regularly, the greater the structural and functional connectivity increases. Findings also show a direct correlation between connectivity increases and severity of use.

Although increased structural wiring declines after six to eight years of continued chronic use, marijuana users continue to display more intense connectivity than healthy non-users, which may explain why chronic, long-term users “seem to be doing just fine” despite smaller OFC brain volumes, Filbey explained. Further studies are needed to determine the permanence and causality of these changes.

CENTER GOINGS-ON

A n estimated 8% of Americans will suffer from post-traumatic stress disorder (PTSD) at some point during their lifetime. Brought on by an overwhelming or stressful event or events, PTSD is the result of altered chemistry and physiology of the brain. Understanding how threat is processed in a normal brain versus one altered by PTSD is essential to developing effective interventions.

New research from the Center for BrainHealth published in Brain and Cognition illustrates how fear arises in the brain when individuals are exposed to threatening images. This novel study is the first to separate emotion from threat by controlling for the dimension of

Br A I N H E A Lth

Tip

Our brain can become less fit with age when we accept mental slippage. Make a New Year’s resolution to put your brain up front and center. You are never too young or too old to adopt brain healthy habits that challenge and enhance your brain to think and act smarter.

TO DO: Schedule a BrainHealth Physical to establish a benchmark of brain health so that you will always be able to tell if your brain is going forward or backward.

To schedule, contact Jennifer Zientz: jennifer.zientz@utdallas.edu

972.883.3404 arousal, the emotional reaction provoked, whether positive or negative, in response to stimuli. Building on previous animal and human research, the study identifies an electrophysiological marker for threat in the brain. brain’s memory center – the hippocampus – before traveling to the frontal lobe where thought processing areas are engaged. At the same time, beta wave activity indicates that the motor cortex is revving up in case the feet need to move to avoid the perceived threat.”

“We are trying to find where thought exists in the mind,” explained John Hart, Jr., M.D., BrainHealth’s Medical Science Director. “We know that groups of neurons firing on and off create a frequency and pattern that tell other areas of the brain what to do. By identifying these rhythms, we can correlate them with a cognitive unit such as fear.”

Utilizing electroencephalography (EEG), Dr. Hart’s research team identified theta and beta wave activity that signifies the brain’s reaction to visually threatening images.

“We have known for a long time that the brain prioritizes threatening information over other cognitive processes,” explained Bambi DeLaRosa, the study’s lead author. “These findings show us how this happens. Theta wave activity starts in the back of the brain in its fear center – the amygdala – and then interacts with the

For the study, 26 adults (19 female, 7 male), ages 19-30, were shown 224 randomized images that were either unidentifiably scrambled or real pictures. Real pictures were separated into two categories: threatening (weapons, combat, nature or animals) and nonthreatening (pleasant situations, food, nature or animals). While wearing an EEG cap, participants were asked to push a button with their right index finger for real items and another button with their right middle finger for nonreal/scrambled items. EEG results revealed that threatening images evoked an early increase in theta activity in the occipital lobe (the area in the brain where visual information is processed), followed by a later increase in theta power in the frontal lobe (where higher mental functions such as thinking, decisionmaking, and planning occur). A left lateralized desynchronization of the beta band, the wave pattern associated with motor behavior (like the impulse to run), also consistently appeared in the threatening condition.

This study will serve as a foundation for future work that will explore normal versus abnormal fear associated with an object in other atypical populations including individuals with PTSD.

February 3

The Emy Lou & Jerry Baldridge Lecture The Winner Effect: How Power Affects Your Brain

Dr. Ian Robertson

The most underestimated brain enhancing agent is empowerment, Dr. Robertson argues. Power’s effects on the dopamine system in particular can enhance cognitive and emotional function but in excess can disrupt them. How can we harness the effects of power and empowerment to get the most out of our brains at every age?

February 10

The Terry & MG (R) Lee Baxter Lecture | Heartbreak to Healing: How One Warrior’s Parents are Waging War Against Veteran Suicide

Dr. & Mrs. Howard Somers, moderated by Krys Boyd (KERA Think!)

“Too trapped in war to be at peace, too damaged to be at war” were the words Army Veteran Daniel Somers wrote in a note for his family before he took his own life on June 10, 2013. His parents, Jean and Howard Somers, are determined to use their son’s death to raise awareness of the struggles veterans face once home, expose gaps in healthcare for service members and repair a broken Veterans Affairs system. Learn how they are taking their fight from Washington, D.C. to the California coast and how you can join their efforts to affect positive change now.

February 17

The Bert Headden & Cindy Thomas Lecture | Utilize Your Brain’s Plasticity for Brain Health

Dr. Michael Merzenich

There’s a revolution in the understanding of the origins of our human abilities. We now know that the brain is continually “plastic,” subject to improvement at any age in life. How can we marshal this great human asset to optimize our well-being and health? Dr. Merzenich, who is often called “the father of brain plasticity,” will share the latest research and discuss how the things we do every day can change our brains for the good—or the bad.

February 24

The Brain Science Behind Golf:

Why Some Experience the “Yips”

Dr. Debbie Crews

What happens when an athlete, who has undoubtedly dedicated their life to training for the perfect performance, suddenly loses all control when it counts the most? Dr. Crews will share the fascinating behavioral, cognitive, and psychophysiological science behind getting the “yips” in the game of golf and learning to play with the yips. The brain pattern of “yippers” and “golfers who help the ball into (out of) the hole” (also known as manipulators) look very similar, but for some golfers this can change with training. Yippers and manipulators can learn to get the ball in the hole!