Our Lives With Post Traumatic Stress Disorder and Traumatic Brain Injury

Posts tagged “frontal cortex

Physiological Changes in PTSD

PTSD causes many things to change. These changes are all encompassing. Physical, psychological and social changes can affect every aspect of our lives. In this article I want to share what some of those changes are and how they affect someone with PTSD.

First, lets look at the physical changes. Studies have shown that there are structural changes that occur in the brains of people with PTSD.

It is known that sensory input, memory formation and stress response mechanisms are affected in patients with PTSD. The regions of the brain involved in memory processing that are thought to cause these changes in PTSD include the limbic system (amygdala, hippocampus) as well as the frontal cortex. While the heightened stress response is likely to involve the thalamus, hypothalamus and the locus coeruleus.

Limbic System: The limbic system, sometimes referred to as the “emotional brain,” is a group of brain structures located deep within the cerebrum. It is composed of the amygdala, the hippocampus, and the hypothalamus. These three structures are involved in the expression of emotions and motivation, particularly those related to survival. Such emotions include fear, anger, and the “fight or flight” response. The limbic system is also involved in feelings of pleasure that reward behaviors related to species survival, such as eating and sex. In addition, limbic system structures have functions related to memory storage and retrieval, particularly memories related to events that invoked a strong emotional response.

Amygdala: The amygdala contains some of our most primal instincts. One of these physical events associated with fear is often called the “fight or flight” reaction:  increased heart rate and force of each beat (“pounding heart”); increased muscle tension that can even cause tremors; sweaty but cold palms; and even nausea and diarrhea.  Another aspect of fear is a physical “conditioning”, so that even a minor stimulus can bring on the whole fear reaction. The amygdala seems to respond to severe traumas with an un-erasable fear response. It seems to be genetically different and “wired” for a higher level of fear in some individuals, such as those with panic disorder or PTSD.

Hippocampus: The hippocampus is part of the limbic system and is responsible for transferring information into autobiographical and fact memory. It may function as a memory “gateway” through which new memories must pass before entering permanent storage in the brain. Hippocampal damage can result in anterograde amnesia (loss of ability to form new memories, although older memories may be safe). Thus, someone who sustains an injury to the hippocampus may have good memory of his childhood and the years before the injury, but relatively little memory for anything that happened since. MRI studies have shown marked changes in this area of the brain in those with PTSD. These changes are thought to be caused by increased exposure to cortisol (the ‘stress’ hormone).

Hypothalamus: The hypothalamus is an area of the brain that produces hormones that control body temperature, hunger, moods, sex drive, sleep, thirst and the release of hormones from many glands, especially the pituitary gland. The pituitary gland is a critical part of our ability to respond to the environment most often without our knowledge.

Prefrontal Cortex: This area of the brain controls cognitive behavior, personality, decision making, and the orchestration of thoughts and actions in accordance with internal goals as well as appropriate social behavior.

Is it any wonder, since PTSD effects so many areas of the brain that every case is very different? Looking at the various symptoms of PTSD, you can begin to see the correlation to the various parts of the brain. Memories, avoidance, hyperarousal can all be linked back to physical changes in the brain.

When you really look at the physiological changes, you can see the reasons behind the reactions in a person with PTSD. These aren’t things that we choose to happen. Our brains have been traumatically rewired. The way thoughts and experiences are processed are vastly different than those without PTSD. The slightest trigger can cause a ‘fight or flight’ response that we cannot control. Adrenaline surges through our bodies at inappropriate times (such as someone accidently dropping a box, what would normally cause a simple startle reaction instead causes us to reach in a much more visceral way).

Perhaps as the medical community continues to learn more about brain function as well as the effects of PTSD and TBI on the brain, more treatments and preventative measures can be discovered. Until that time comes, we continue our fight against PTSD.