Preface

The purpose of this course is to help the college-level student attain a thorough understanding of the field of neuroscience. Neuroscience as a discipline might seem new, however, researchers have studied aspects of neuroscience for at least a century scientifically and have speculated on issues related to neuroscience since antiquity. Since the time of Hippocrates, philosophers have wondered about issues related to consciousness, emotions, and sleep—questions that have largely been answered through modern research in more recent times.

In this course, we will talk about the nervous system in its entirety, starting with the anatomy of the nervous system and then talking about things like neural development, nerve cells and their function, neural pathways, and neurotransmitters. We will then break down the different parts of the nervous system to include the motor aspects, sensory aspects, and unconscious parts of the nervous system, such as the autonomic nervous system. Finally, we will talk about what is known about consciousness, sleep, emotions, and intelligence that have come out of sophisticated theories and research about how our amazing nervous systems work throughout our lives.

Chapter one in the course opens the discussion of neuroscience with the basic anatomy of the nervous system as a whole. The central nervous system is the brain and spinal cord together, while the peripheral nervous system involves the nerves that travel throughout the rest of the body. There are superficial brain structures and deep brain structures covered in this chapter. The basic pathways of the spinal cord are also talked about in the chapter as well as what peripheral nerves look like in the body. This will provide you with a foundation you will build on in the rest of the course.

In chapter two, we go microscopic and talk about nerve cells and their supporting cells, called glial cells. As you will see, nerve cells have an unusual shape with a central cell body and several projections coming from them, called dendrites and axons. We will talk about how nerves interact with each other at synapses and will talk about how

electrical signals travel along the dendrites and axons. Finally, we will describe the blood-brain barrier, which separates the brain from the rest of the body.

Chapter three in the course is all about the beginnings and development of the nervous system in humans. Humans begin as a one-celled organism but within a few weeks, there is the development of a primitive nervous system that continues to develop at a rapid pace, even before birth. As you will see, there is advancement of the nervous system development throughout life, even as there isn’t a great potential for new nerve cells to develop after birth. This leads to the concept of neuroplasticity, which is the potential for nerve pathways to be created or to change and for pathways to either strengthen or dissipate over time in order to keep the nervous system from being a static organ system throughout a person’s life.

The purpose of chapter four is to cover all of the major neurotransmitters and neurotransmitter systems commonly used in the nervous system. Neurotransmitters are the chemical messengers of the nervous system and allow for postsynaptic nerve cells to be excited or inhibited in their response. In the chapter, we will talk about what makes a neurotransmitter excitatory versus inhibitory and which ones tend to have what kinds of effects on mood, thinking, and behavior.

In chapter five of the course, we will isolate out the motor nervous system involving the parts of the brain and peripheral nervous system that generate movement. Most, but not all, movement is voluntary but is not truly disconnected from the sensory system, which helps to direct the accuracy and appropriateness of movement. In the chapter, we will cover everything that leads to movement—from the cortical motor areas, through motor pathways, and to the lower motor neurons and the neuromuscular junction at the level of the muscles.

The focus of chapter six is the sensory nervous system, which is just as complex as the motor system. We will talk about the somatosensory cortex, where sensations are interpreted as well as the different receptors available for the sensations of touch, temperature, vibration, proprioception, and pain. There are spinal tracts that carry this information through the thalamus and into the somatosensory cortex. How sensations like pain get interpreted and modulated will also be discussed as part of this chapter.

The main topic of chapter seven in the course is the autonomic nervous system, along with the related topic of the enteric nervous system. Both of these are involuntary neural systems that regulate all of the body processes that happen without a great deal of conscious thought, such as heart rate, blood pressure, gastrointestinal function, sweating, sexual function, and bladder control. These are considered subconscious even though we have conscious awareness of them and some voluntary control over them. In the chapter, we will talk about the different branches of this system and how the different aspects of the body are regulated using the various autonomic nerves.

Chapter eight focuses entirely on the cranial nerves, which are specialized nerves that do not come off the spinal cord but instead come off parts of the brain proximal to the spinal cord through individual nuclei. These cranial nerves are unique as they are not only sensory and/or motor nerves but also sometimes have special sensory functions, such as those related to the major special senses like taste, vision, olfaction, and hearing. In this chapter, we will talk about the anatomy and basic physiology of each of the twelve cranial nerves.

The focus of chapter nine in the course is the special senses. These consist of senses that are termed chemical senses and those that are termed mechanical senses. We will first talk about the chemical senses of taste and olfaction. Other special senses discussed in this chapter are the sense of vision and the sense of hearing. Separate from this is the sense called vestibular sense, which relates to balance and posture. How these senses work at the receiving organ is the main focus of this chapter.

Chapter ten talks about the neuroscience behind human memory and the importance of memory with regard to human behavior, thinking, and functioning. Memory is interesting and multidimensional. There are differences in the memory required to do physical tasks like riding a bike and the memory necessary to remember a grocery list or to think about one’s past. The structure and function of the brain areas responsible for memory are also covered in this chapter.

Chapter eleven in the course delves into the neuroscience behind our human emotions. Having emotions is essential to being human and yet so many human disorders are directly influenced by emotions or are a result of disordered emotions. In

this chapter, we will talk about the limbic system, which is the seat of human emotions in the brain and will talk about how this system has projections to other body and brain areas so we can experience emotions on a cortical and visceral level.

Chapter twelve focuses on the association cortices in the brain, which together provide the basis for cognition. Cognition itself is complex but it is believed to involve the way the association cortices process sensory input and then generate thoughts and behaviors. In this chapter, we will talk about the inputs of the frontal lobe neurons, the temporal lobe neurons, and the parietal lobe neurons when it comes to cognitive processes in the human brain.

Chapter thirteen in the course concerns itself most with the concept of sleep and about what represents wakefulness. Sleep is complex and has many stages which appears to represent different physiological functions in the body. Sleep happens in most people that is dependent on the Circadian rhythm, which is covered in this chapter. The subject of dreams and why we have them is also discussed. There are different pathways that determine sleep and wakefulness that are covered as well in this chapter.

Chapter fourteen is about how the human brain participates in both the production of speech and the appreciation or understanding of speech. As we will discuss, there is not just a single language center in the brain but rather two major centers. Speech is therefore lateralized and relies on connections between these areas in order to have the ability to participate in human language. Disorders of language will also be covered in this chapter.