Textbook: Physiology of Behavior, Chapter 2 and Chapter 4 (pp. 89–101)
Physiology of Behavior
Neil R. Carlson and Melissa A. Birkett
Pearson
Thirteenth Edition
2021
Module Overview11.html
Structure and Function of the Nervous System
The Nervous System
The nervous system is a complex network that controls all physical and cognitive processes. The central nervous system (CNS) includes the brain and the spinal cord. The peripheral nervous system (PNS) includes nerves reaching the body’s appendages, the cranial nerves, and all organs. The CNS is involved in all parts of the transmission of information, including reception, processing, and storage. This intricate bodily system is what makes behavior possible.
The nervous system’s activity modifies its performance. The system receives signals from the environment and sends them throughout the body to the spinal cord and the brain for processing. The information (response) is sent from the brain or the spinal cord to various body parts in response to environmental conditions. It leads to new signal pathways to modify behavior, as appropriate.
The Neuron
The neuron is the brain’s basic unit and the workhorse of all CNS functions. At the simplest level, a neuron contains:
- A cell body that houses the cell’s important life functions
- An axon that carries information toward other cells
- Dendrites that receive information from other cells
The neuron works through electrochemical mechanisms. It releases neurotransmitters (the brain’s communication chemicals). The release of neurotransmitters helps communication from one neuron to the next in the chain. Neurotransmitters trigger an action potential, or electrical signal, when they reach the next neuron. This electrical signal travels inside the neuron. Then the cycle repeats itself. The brain has dozens of neurotransmitters, but perhaps the most important ones to neuropsychology include the amines. These amines include serotonin, dopamine, norepinephrine, and acetylcholine (Stahl, 2011). Chemical communication in the brain can be from cell to cell across the synapse. Communication can also be more diffuse, which is known as volume transmission (Srivastava et al., 2022). Psychotropic medications act on the brain through volume transmission. Therefore, the process is of significant clinical importance.
The Developing Nervous System
At birth, the brain is about 25% of its adult weight. In other words, it is disproportionally large compared to the rest of a newborn’s body. At the same time, a newborn’s body is only about 5% of its adult weight. The brain is about 75% of its adult weight by age two. Pediatricians measure head circumference during this critical growth period to gauge how the brain is growing.
The brain continues to develop throughout infancy, childhood, adolescence, and even into young adulthood. However, the first two years of life are a time of dramatic change. Most neurons are created before birth and already send and receive electrochemical impulses. At birth, the brain contains many more neurons than a person needs. A process called apoptosis eliminates excessive neurons. This process can be likened to cell death prompted by genetic instruction (Stahl, 2011). These critical first couple of years are a time of rapid growth of axons, dendrites, and synapses (particularly in the cortex). It is also a time of refinement. Frequently used pathways become stronger. Unused pathways atrophy—a process known as synaptic pruning (Stiles, 2008).
The process of synaptic pruning highlights the importance of early experiences in a child’s life. Expansion and pruning occur during every aspect of an infant’s life. This process includes listening, using language, and hearing musical rhythms. It also occurs from when children experience the world around them to when they begin to understand emotions. For typical development to occur, infants must have typical early experiences that strengthen certain connections in the brain (Kohlasch et al., 2021).
Neuron proliferation and pruning take place in infancy. A critical process called myelination also occurs in infancy. Myelination develops the myelin sheath that coats the axons. This fatty layer is important to processing speed. It allows electrical signals to travel more quickly through the neuronal network. Much of this myelination occurs in the first few months of life. Think of myelin as the plastic coating (insulation) on electrical wires. The coating prevents short-circuiting and permits a better transfer of electricity. The better the coating, the better protected the current. Thus, myelination is directly related to brain efficiency. This efficiency is known cognitively as processing speed. Disorders such as multiple sclerosis are linked to myelin damage that results in physical, cognitive, and emotional symptoms.
Human development involves important brain phases of development before and after birth. Apoptosis and synaptic pruning refine the brain while other areas continue to develop. For example, the frontal lobes are not fully developed until about the mid-20s.
References
Kohlasch, K. L., Cioffredi, L.-A., Lenninger, C., Stewart, E., Vatalaro, T., Garavan, H., Graham, A., Heil, S. H., Krans, E. E., Robakis, T., Rommel, A., Sullivan, E. L., Thomason, M., & Potter, A. (2021). Factors associated with parent views about participation in infant MRI research provide guidance for the design of the Healthy Brain and Child Development (HBCD) study. Developmental Cognitive Neuroscience, 50. https://doi-org.ezproxy.snhu.edu/10.1016/j.dcn.2021.100986.
Stahl, S. M. (2011). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications (3rd ed.). Cambridge University Press.
Stiles, J. (2008). The fundamentals of brain development: Integrating nature and nurture. Cambridge, MA: Harvard University Press.
Srivastava, P., Fotiadis, P., Parkes, L., & Bassett, D. S. (2022). The expanding horizons of network neuroscience: From description to prediction and control. NeuroImage, 258. https://doi-org.ezproxy.snhu.edu/10.1016/j.neuroimage.2022.119250
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Reading and Resources1.html
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Required Resources |
Textbook: Physiology of Behavior, Chapter 2 and Chapter 4 (pp. 89–101)
Library Article: Neuronal Communication This article explains the importance of neural communication for the medical treatment of different diagnoses.
Website: Neuroanatomy Tutorial – Labeled Images This neuroanatomy tutorial from the University of Utah includes images from all views of the brain and can help you visualize neural networks and electrical signals. This UT resource offers a unique visual breakdown of the brain from different angles.
Website: Introduction – Overview of the Nervous System This resource reviews the human nervous system and discusses the roles of the central nervous system and the peripheral nervous system.
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2-1 Discussion: The Brain-Behavior Relationship
The brain consists of an estimated 100 billion neurons. Each neuron can have thousands of connections to other neurons. Also, there are an estimated 10 times the number of glial cells (support cells) as there are neurons. In other words, the brain's communication system is complex. In your discussion post, address each of the following questions:
● How is the brain's complex network of neurons key to the brain–behavior relationship?
● What is the cellular process of information transfer within the brain? Discuss.
● What is the process of information transfer between the brain and the body? Discuss.
● What types of developmental problems could result from childhood disruption of neural systems? Consider emotional, cognitive, or physical problems.
When responding to peers, consider the neural communication process in their post. Can it lead to establishing patterns of behavior? For example, if the post is about slowed neural communication, how does it affect their school and home functioning?
To complete this assignment, review the Discussion Rubric.
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Graduate Discussion Rubric.html
Graduate Discussion Rubric
Overview
Your active participation in the discussions is essential to your overall success this term. Discussion questions will help you make meaningful connections between the course content and the larger concepts of the course. These discussions give you a chance to express your own thoughts, ask questions, and gain insight from your peers and instructor.
Directions
For each discussion, you must create one initial post and follow up with at least two response posts.
For your initial post, do the following:
- Write a post of 1 to 2 paragraphs.
- In Module One, complete your initial post by Thursday at 11:59 p.m. Eastern.
- In Modules Two through Ten, complete your initial post by Thursday at 11:59 p.m. of your local time zone.
- Consider content from other parts of the course where appropriate. Use proper citation methods for your discipline when referencing scholarly or popular sources.
For your response posts, do the following:
- Reply to at least two classmates outside of your own initial post thread.
- In Module One, complete your two response posts by Sunday at 11:59 p.m. Eastern.
- In Modules Two through Ten, complete your two response posts by Sunday at 11:59 p.m. of your local time zone.
- Demonstrate more depth and thought than saying things like “I agree” or “You are wrong.” Guidance is provided for you in the discussion prompt.
Discussion Rubric
Criteria | Exemplary | Proficient | Needs Improvement | Not Evident | Value |
---|---|---|---|---|---|
Comprehension | Develops an initial post with an organized, clear point of view or idea using rich and significant detail (100%) | Develops an initial post with a point of view or idea using appropriate detail (90%) | Develops an initial post with a point of view or idea but with some gaps in organization and detail (70%) | Does not develop an initial post with an organized point of view or idea (0%) | 20 |
Timeliness | N/A | Submits initial post on time (100%) | Submits initial post one day late (70%) | Submits initial post two or more days late (0%) | 10 |
Engagement | Provides relevant and meaningful response posts with clarifying explanation and detail (100%) | Provides relevant response posts with some explanation and detail (90%) | Provides somewhat relevant response posts with some explanation and detail (70%) | Provides response posts that are generic with little explanation or detail (0%) | 20 |
Critical Thinking | Draws insightful conclusions that are thoroughly defended with evidence and examples (100%) | Draws informed conclusions that are justified with evidence (90%) | Draws logical conclusions (70%) | Does not draw logical conclusions (0%) | 30 |
Writing (Mechanics) | Initial post and responses are easily understood, clear, and concise using proper citation methods where applicable with no errors in citations (100%) | Initial post and responses are easily understood using proper citation methods where applicable with few errors in citations (90%) | Initial post and responses are understandable using proper citation methods where applicable with a number of errors in citations (70%) | Initial post and responses are not understandable and do not use proper citation methods where applicable (0%) | 20 |
Total: | 100% |