What regions of the brain are believed to be associated with post-traumatic stress disorder (PTSD)? Discuss the anatomy/physiology of the pathologic process of PTSD. Specifically focus on how normal anatomy/physiology has been altered.
A psychological “jolt” to the system can definitely trigger a depressive – even suicidal – state in the average human physiology. When that jolt is triggered by the unique and often protracted stresses and horrors associated with combat, the physiological transformations that occur can be difficult to reverse. Historically referred to as “combat neurosis,” “battle fatigue,” or “shell-shock,” what is today more commonly labeled “post-traumatic stress disorder” (PTSD) has been traced – courtesy of the development of highly-advanced imaging technologies -- to the physical transformations that occur within the brain when exposed or subjected to extraordinarily disturbing or horrific events, such as the sight of one’s friends being brutally killed or maimed in battle. Such symptoms of PTSD as recurring nightmares or flashbacks, anxiety, accelerated heart beat and accompanying sweating and, in some cases, intestinal disorders, feelings of guilt (often referred to as “survivor’s guilt”), memory loss, lethargy and depression are all a result of the transformative processes that have occurred in the brains of those subjected to horrific events. [It should be noted that, while the emphasis so far has been on military-related experiences, PTSD affects victims of all types of horrific events, including rape, natural disaster, and more]
The specific areas of the brain involved in PTSD are components of the "Limbic System," which runs through the central brain and is composed of the thalamus, hypothalamus, amygdala and hippocampus, which is the part of the brain associated with memory. With respect to the amygdala, one report noted that “brain activity in the amygdala, a key structure in the brain’s ‘fear circuitry’ that processes fearful and anxious emotions, was significantly higher in the 52 combat veterans with PTSD than in the 52 combat veterans without PTSD.” This same report also showed “elevated brain activity in the anterior insula, a brain region that regulates sensitivity to pain and negative emotions.” [See Rick Nauert, Ph.D., “Even Without Stress, PTSD Effects Persist in Brain Regions,” PsychCentral, May 20, 2013]
Many studies of PTSD have focused on the hypothalamus, a tiny part of the thalamus located at the brain stem. The primary function of the hypothalamus is to regulate the body’s neurological system. The various symptoms of PTSD, including accelerated heart rate, perspiration, blood pressure, chemical balances, etc., are all tied in with the hypothalamus. The neurotransmitters that connect the key areas of the brain to other parts of the body are essentially the body’s electrical system, and exposure to traumatic events can upset the electrical impulses that move between the regions of the brain involved and other organs, especially the gastrointestinal system, which produces serotonin, as well as the central nervous system. The chemical reactions that occur as a result of disturbances to the normal flow of electrical signals can physically rearrange the parts of the brain responsible for regulating mood, sometimes permanently. The chemical imbalances that result from disruptions to the normal function of the neurotransmitters can often be treated with prescription medications like Selective Serotonin Reuptake Inhibitors (SSRIs), which block the absorption of serotonin in the brain by interacting with the neurotransmitters.
The areas of the brain that are associated with PTSD are the prefrontal cortex, amygdala, and hippocampus. People with this disorder have a smaller volume of their hippocampus compared to those without it. The amygdala is believed to be involved in the formation of emotional memories, especially those related to fear.