The brain is the control center of the body, it is a part of the central nervous system and controls all mental and physical actions. Most sensory systems of the body are located within parts of the brain allowing for the interpretation of many different senses. The intake and addiction to drugs can alter a great deal of brain activity, dysregulating typical brain function. Drugs can create an interference in how neurotransmitters send and receive signals. Some drugs can have the ability to activate neurons due to mimicking the natural neurotransmitter, other drugs can cause an influx and excess release of neurotransmitters. There are many structures in the body that are altered by the use of drugs, the three brain structures I want to focus on are the basal ganglia, amygdala, and the prefrontal cortex.
Basal ganglia play the important role of reward based motivation where it acts as a reward circuit where behavior is learned. When drugs or substances are overused it becomes problematic as there is an overproduction of dopamine in the basal ganglia. The body adapts to the surge and excess of dopamine causing tolerance in the body to dopamine. After the body creates a new tolerance to dopamine it decreases the overall effect dopamine has on an individual, this decreases the amount of pleasure received from any activity that may have previously caused pleasure. The tolerance to dopamine in the basal ganglia is part of the reason why drug users increase their intake more and more in order to receive a similar euphoric or high feeling. Reward based motivation trains high behaviors as it associates happiness with the intake of drugs or situations in which drugs are frequent. The basal ganglia are altered by the use of drugs both by tolerance to dopamine and amplifying learned drug based motivations.
Another important structure of the brain that is altered by drug use is the amygdala. Parts of the amygdala are responsible for the body's stress response. The amygdala drives the body away from stressful situations and pushes individual’s to escape the situation that causes stress. An issue with drugs is that as a person experiences withdrawal from drugs there is unpleasant stress. After extended periods of taking drugs there is a shift in the amount of stress and discomfort an individual feels when withdrawing from drugs, this then leads to negative reinforcement. When drugs are taken the adverse stimulus of negative physical and emotional pain from withdrawal is removed. This leads to a constant cycle of continued drug use in order to halt the pain from not having drugs.
The prefrontal cortex plays a major role in daily life of decision making, impulses control, and problem solving. One major thing that is often thought about drug users is the extreme emotions that are felt, this is due to damage to the prefrontal cortex. The prefrontal cortex helps with regulating emotions and suppression of extreme emotions which means after the prefrontal cortex is damaged with prolonged drug use then emotional outburst can become frequent and unpredictable. The dysfunctional prefrontal cortex creates all impulses and decisions to begin to revolve around drugs themselves. An altered way of thinking puts drugs at the center of the user's life due to increased intrusive thoughts purely focused on drugs.
As a whole it is evident that extended drug use alters brain function negatively. Unfortunately the way the brain reacts to drugs leads to a difficult cycle to break. The basal ganglia decreases sensitivity to dopamine causing the main form of happiness to be drug induced. The amygdala creates a pattern of drug based on negative reinforcement and drugs are repeatedly taken to reduce negative physical and emotional states. Overall the altered thinking of impulses and decision making continues the cyle as the prefrontal cortex is altered. Drugs impact the brain in such a way that repeated use becomes rewarding and unfortunately can easily cause addiction.
Sources:
Goldstein, R. Z., & Volkow, N. D. (2011). Dysfunction of the prefrontal cortex in addiction: neuroimaging findings and clinical implications. Nature reviews. Neuroscience, 12(11), 652–669. https://doi.org/10.1038/nrn3119
Koob G. F. (2009). Brain stress systems in the amygdala and addiction. Brain research, 1293, 61–75. https://doi.org/10.1016/j.brainres.2009.03.038
NIDA. (2022) Drugs and the Brain. https://nida.nih.gov/publications/drugs-brains-behavior-science-addiction/drugs-brain
Rebekah, I thought your topic was really interesting. I especially liked how that you talked about the specific parts of the brain that were affected by various drugs, and the specific reasons for why these parts of the brain are important. The explanation of the parts I thought was very helpful in explaining the actual gravity of drug use.
ReplyDeleteI love your thoughts here. It is interesting that you got so much about how drugs affect the nervous system. I think that it is amazing that we can design drugs that have such a great influence on our body systems
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