Lesson 3: Basic Neuropsychology and Genetic Issues Attention Take a look at this video regarding the basic structures and functions of the brain. Learning Outcomes Upon completion of this lesson's material, students will
Reading Chapter 2 in Facing Addiction in America Teaching
THE CENTRAL NERVOUS SYSTEM All behavior is grounded in the Central Nervous System (Brain/Spine) This does not mean that we are maintaining materialism or determinism as explanatory of substance disorders but rather that explanation begins with the CNS The CNS operates through neurons: cells that send messages through chemical mediators (neurotransmitters) that are related to electrical activity in the neuron The neuron depicted above is typical: all you need to know is that at each end, there are structures capable of emitting and absorbing chemicals that communicate with adjacent neurons, and that between the two ends, an electrical impulse is transmitted through the Schwann cells so that the chemical message received at one end is passed on to the other end electrically. It is this electrical activity that is picked up in electroencephelograms. Mental disorders including substance disorders seem to be causally related to excesses or deficiencies of these chemical mediators that communicate between neurons. The CNS is composed of the Brain and Spine and the Spine is how information gets to and from the brain while the brain is where information is processed (sensations, perceptions, thoughts and feelings) and acted upon (behavioral initiation and execution in terms of reflexes and operants as well as homeostatic regulation of organs) Part of the CNS largely located in the Spine ( but also involving the mid brain and hind brain) is the Autonomic (self-regulating, self-ruling) Nervous System which regulates our bodily systems largely without conscious involvement Here is a picture representing how the Autonomic Nervous System is responsible for specific functions. The Autonomic Nervous System (ANS), pictured above, is subcortical and involves the brain stem and spine, areas 3 and 5 of the Central Nervous System. The ANS as you can see is separated into Sympathetic (in the sense of being coordinated with arousal and our feelings---anger, fear, fight or flight) and Parasympathetic (in the sense of acting in a different direction than the Sympathetic being associated largely with resting and relaxing) The ANS is also involved in SUDS with stimulants largely affecting the Sympathetic (through epinephrine---adrenaline--- with its associated sense of excitement) and sedatives largely affecting the Parasympathetic (through aceylcholine which in this case produces relaxation) and in each case being a valued part of the "high" Although the ANS is "involuntary", our thoughts can affect it. By imagining ourselves on a roller coaster, for example, we can produce epinephrine and raise heart rate and blood pressure. By imagining an erotic image we can produce genital sensations and even orgasm NEUROTRANSMITTERS Neurons sensitive to these mediators are found throughout both Central and Peripheral Nervous Systems and the transmitters may act in significant ways at any point so that there may be very complex interactions that finally explain the observed behavior.
The GABA/Glutamate System
Cannabis Receptors
OTHER CNS FACTORS There are many other CNS factors and dynamics that affect substance use so that we should not think that understanding this neurochemistry has completely explained substance dependence. But this understanding is valuable towards beginning to think about how to help. For example, if there is a specific nicotine receptor in the CNS, then perhaps a medication that affects this receptor will help people to stop smoking. This is the idea behind Chantix which is a medication that blocks the nicotine receptor making people think they have already had a cigarette and keeping them from craving another. Another example is Naltrexone which blocks opiate receptors and can be helpful in the treatment of both opiate and alcohol addiction because it somewhat reduces craving. Finally, we need to understand that although nothing happens without the CNS, understanding whats going on in the CNS is not an exhaustive explanation of the behaviors with which we are concerned. For example, knowing that a genetic deficiency in dopamine receptors in the limbic system explains why some people become addicted practically from their first use of substances does not explain the whole phenomenon of addiction even in a single instance. In each case there are always other psychological, social and even spiritual factors involved which help us to understand the case under consideration in a practical and helpful way. Assessment In this section you will find a list of the required Assessments that accompany this Lesson. The Lesson Discussions are designed for the ONLINE and HYBRID versions of this course. If you are not in an ONLINE or HYBRID version of this course you can ignore these instructions unless otherwise guided by your instructor. Lesson 3 Quiz
Lesson 3 Discussion Write a paragraph describing what you think about the relationship of the brain to addiction. Write another paragraph stating what factors influence addiction in addition to the brain and which factors in your experience have been most important in cases of addiction that you have seen.
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