Neurological Processes
Ugur Unal
PSY/340
July 15th, 2016

Neurological Processes The brain is the most complex part of the body. This organ is the center of intelligence, interpreter of the senses, initiator of body movement, and controller of behavior. For centuries, scientists and philosophers have been infatuated by the brain, but until recently the brain has been viewed as perplexing. Now, however, the brain is beginning to show its secrets. Scientists have learned more about the brain in the last few years than in all previous centuries because of the accelerating pace of research in neurological and behavioral science and the development of new research techniques. The brain is like a committee of experts. All the parts of the brain work together, but each part has its own special properties. Biological causes of clinical depression continue to be studied extensively. Great progress has been made in the understanding of brain function, the influence of neurotransmitters, and other biological processes, as well as how they may relate to the development of depression. Depression or anxiety causes individuals to have many changes in their behaviors. They tend to become isolated from their family, friends, or be social. Their eating patterns lead to either weight gain or loss; and sleeping patterns change where they either do not sleep or sleep excessively. They become agitated, irritable, and fatigue or have lack of energy. Biological psychology aims at finding the biological factor of depression. Selective serotonin reuptake inhibitors, (SSRI) have had a major impact on the field of biological psychology because it is the most commonly prescribed medication for the treatment of depression and other mental disorders including anxiety and obsessive disorder. The brain is the "command center" of the human body. It controls the basic functions of our bodies, our movements, and our thoughts and emotions. Researchers studying clinical depression tend to look at several aspects of brain function including the structures of the limbic system and the function of neurotransmitters within neurons. Those who research clinical depression have been interested in a particular part of the brain called the limbic system. This is the area of the brain that regulates activities such as emotions, physical and sexual drives, and the stress response. The activities of the limbic are so important and complex that disturbances in any part of it, including how neurotransmitters function, could affect your mood and behavior. Neuropsychology involves the study of healthy individuals, especially those who have suffered either brain injury or mental illness. Cognitive neuropsychology and cognitive neuropsychiatry study neurological or mental impairment in an attempt to infer theories of normal mind and brain function. This typically involves looking for differences in patterns of remaining ability (known as 'functional disassociations') which can give clues as to whether abilities are composed of smaller functions, or are controlled by a single cognitive mechanism. There has been a great debate about illnesses such as depression and anxiety and if the reaction is a chemical imbalance or because of natural events in life. There is no doubt that our feelings are in fact complex chemical, electrical and neurological processes that occur in our brain. According to some advocates, depression is caused by small amounts of certain neurotransmitters such as serotonin, dopamine and norepinephrine in the brain. These advocates do not deny that emotions are chemically, electrically and neurologically based, but believe that all emotions are simply the brain’s reaction to external events, regardless of severity or consequence of depression or anxiety. Postsynaptic potentials, both excitatory and inhibitory, along with synaptic transmission, and receptors, have a role in producing and regulating behavior. Postsynaptic potential is a change in the resting potential after being stimulated by the presynaptic cell. "If all this stimulation causes the voltage inside the cell to become more positive, this is called an excitatory postsynaptic potential (EPSP), and if the cell becomes more negative, it is called an inhibitory postsynaptic potential (IPSP)" (Wickens, 2005 p.19). The accumulation of these nerve impulses causes electrical movement inside of the synapses known as synaptic transmission or neurotransmission. Synaptic transmission allows communication between neurons. All experiences, such as thoughts and feelings, and all actions, are the results of neurons generating nerve impulses. The receptor is the part of the cell that binds with certain transmitters or molecule, which cause psychological changes to occur. Neurotransmitters are essentially chemical messengers, which are pre programmed to send messages throughout the body and brain. There are over 100 different types. The two main neurotransmitters that are responsible for mood, mood stability, energy, feelings, concentration, appetite and others are serotonin and dopamine. There are numerous types of neurotransmitters and chemicals that inhibit the body but there are primary neurotransmitters that play a role in brain function and behavior. These primary neurotransmitters are; noradrenalin, dopamine, serotonin, GABA (gamma amino butyric acid), acetylcholine, and glutamate. Noradrenalin (norepinephrine) is a hormone that "activates the sympathetic nervous system, which increases the concentration of glucose in the blood, raises blood pressure and heartbeat rate, and increases muscular power and resistance to fatigue" (The Internet Encyclopedia of Science). Dopamine is a neurotransmitter that plays many roles within the brain. It has a role in behavior and thinking, as well as motivation, reward, sleep, and mood. Serotonin, like Dopamine, is a neurotransmitter that plays a role in mood regulation and sleep. Serotonin also plays a role in regulating body temperature and sexuality. GABA, or Gamma-amino butyric acid, acts at inhibitory synapses in the brain by binding to specific transmembrane receptors in the plasma membrane of both pre- and postsynaptic neurons. Acetylcholine is a neurotransmitter that is a very effective deliverer or sodium ions, which stimulate muscle contractions and excites nerves. An increase in acetylcholine causes a decreased heart rate and increased production of saliva, as well as readying the muscles for work. (ISCID Encyclopedia of Science and Philosophy, 2008) Finally, Glutamate is an excitatory neurotransmitter that is believed to play a role in cognitive functions. It is of great importance for psychologists to understand the biological roles that neurotransmitters play in the brain in order to understand a majority of mental illnesses. Neurotransmitters are the chemicals emitted by the body that send messages between neurons and other cells. When there is an imbalance or any other type of problem with neurotransmitters, brain function and behavior will suffer the effects. "The discovery of synaptic chemical transmission by Loewi provides one of the pivotal points in the history of biological science-not least because it raised the possibility of modifying brain function (and behavior) by the use of drugs that affect neurotransmitters" (Wickens, 2005 p. 14). A Selective Serotonin Reuptake Inhibitor (SSRI) is one type of drug that can alter the way that neurotransmitters work. Selective serotonin reuptake inhibitors (SSRI) are usually prescribed for depression and other conditions. The neurotransmitters are released by one nerve and then are taken up by other nerves. The neurotransmitters that aren't taken up by other nerves end up getting taken up by the same (original) nerve which has released them. This is what "reuptake" is. SSRIs are antidepressants that work by increasing the extracellular level of the neurotransmitter serotonin by inhibiting its reuptake into the presynaptic cell, increasing the level of serotonin available to bind to the postsynaptic receptor. It is believed that altering the way that chemicals bond within the brain can help alleviate depression, anxiety disorders, and other mental illnesses and SSRIs allowed that to be accomplished. Neurotransmitters control every emotion and thought, memory and learning; they carry the signals between the nerve cells or neurons in the brain. Psychiatric drugs can interfere with just about every step in work of neurotransmitters. (Sahley, 2002) When Serotonin is low, we experience problems with concentration and attention. We become scatterbrained and poorly organized. (Carver, 2006) The lack of concentration and attention leads people to act in ways that are out of character. A person might not perform his or her job duties correctly or accidentally misplace important paperwork and not remember doing it. Physical symptoms such as sleepiness and stomach upset may also appear as they too are side effects of low serotonin. All of these symptoms, both mental and physical, may add to the feelings of despair and sadness which increases the severity of depression. Treatment for depression, as might be expected, involves increasing levels of Serotonin in the brain. Since the mid-eighties, medications have been available to simply target and increase Serotonin. (Carver, 2006) Zoloft (sertraline HCI) is an SSRI that is used to treat depression, anxiety disorders, obsessive-compulsive disorder, along with other mental disorders. Zoloft works by raising serotonin levels which helps to regulate the mood. The goal of prescribing medications such as Zoloft, or any SSRI, is to regulate the chemical imbalance and return it to its normal level within the brain. Mental health professionals use psychological testing, interviews, questionnaires, and patient history to determine first, if a change in the neurotransmitter system is present, then second, what neurotransmitters are involved. (Carver, 2006) Only after these processes can a proper diagnosis and ultimately, treatment, be determined. Theories about how neurotransmitters may be related to a person's mood have been based upon the effects that antidepressant medications can have on relieving depression in some people. It is believed that these medications are effective because they regulate the amount of specific neurotransmitters in the brain. However, the role that neurotransmitters play in the development or treatment of clinical depression is not completely clear. Another reason that the effects of neurotransmitters are not clear-cut has to do with the fact that antidepressant medications do not work for everyone. If there were a direct causal link between the level of a neurotransmitter in the brain and depression, then we would expect a much higher rate of success with medication. Further, although antidepressant medications can change the level of a neurotransmitter in the brain immediately, it normally takes a few weeks for a person with depression to feel better. What is seems to boil down to is that there appears to be a strong relationship between neurotransmitter levels in the brain and clinical depression, and that antidepressant medications work for a great many people, but we are not absolutely certain of the actual relationship between neurotransmitters and depression. The reason we do not know more about the effects of neurotransmitters has to do with that fact that they are so difficult to study. Neurotransmitters are present in very small quantities, they are only available in certain locations within the brain, and they disappear very quickly once they are used. Because they are removed so fast, they cannot be measure directly. Researchers can only measure what is left over after their use in the brain. The substances that remain are called metabolites and they can be found in blood, urine, and cerebrospinal fluid. By measuring these metabolites, researchers can gain an understanding of the effects of changes in neurotransmitters in the brain. It is unknown whether changes in levels of neurotransmitters cause the development of depression or depression causes changes in neurotransmitters. It may happen both ways. Researchers believe that our behavior can affect our brain chemistry, and that brain chemistry can affect behavior. For instance, if a person experiences numerous stressors or traumas this may cause his or her brain chemistry to be affected, leading to clinical depression. On the other hand, that same person may learn how to change depressed thoughts and behavior and cope with stressful events. Doing this may also change brain chemistry and relieve depression. There are many reasons that a person may encounter mental illness, be it circumstantial or chemical. Whatever the reason; biological psychology should be a person's first course of action. The impact SSRIs have had on the field of biological psychology has been huge. Without selective serotonin reuptake inhibitors, there would not be medications available to help those suffering from mental illnesses.

References
Acetylcholine. (2008). ISCID Encyclopedia of Science and Philosophy. Retrieved on September 1, 2010 http://www.iscid.org/encyclopedia/Acetylcholine
Carver, J., (2006). Medication Treatment of the Chemical Imbalance. Retrieved on September 1, 2010 http://www.enotalone.com/article/4119.html
Carver, J., (2006). Serotonin: From Bliss to Despair. Retrieved on September 1, 2010 http://www.enotalone.com/article/4116.html
Noradrenalin. In The Internet Encyclopedia of Science. Retrieved on September 1, 2010 http://www.daviddarling.info/encyclopedia/N/noradrenaline.html
Sahley, B., (2002). Understanding Chemical Imbalances. Retrieved on September 1, 2010 http://web.ebscohost.com/ehost/detail?vid=4&hid=9&sid=385e984f-4531-405c-99df-d9250955aad9%40sessionmgr2
Wickens, A.P. (2005). Foundations of Biopsychology, (2nd ed). New York: Pearson/Prentice Hall