PTSD Effects on the Hippocampus
Post-traumatic stress disorder or PTSD effects the brain when you develop the symptoms associated with PTSD. According to Bremner the part of the brain that is effected is the hippocampus and memory along with emotions. The hippocampus is a portion of the medial temporal lobe of the brain, its functions are memory and emotion. (Figure 1.) When the hippocampus is damaged it causes the person to have problems with memories and also other parts of the brain are effected from the traumatic experience. It is very sensitive to stress, so when there is too much stress the hippocampus can become damaged.
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Another problem that arises when the hippocampus becomes damaged, your ability of learning new material becomes harder for you. That part of the brain is known to regenerate nerve cell and when stress comes with the traumatic event it can cause it to stop or slow down the regeneration. Another area of the brain that is effected by PTSD is the medial prefrontal cortex, it controls emotional and fear responses. (Figure 2) The medial prefrontal cortex is linked to the hippocampus, when both are damaged patients are suffering from PTSD (Bremner 2000).
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Studies Done on the Hippocampus with PTSD
According to Bremner several studies were conducted on the hippocampus and with different types of PTSD. One of the studies were to look to see if the neurons in the hippocampus were lost due to PTSD symptoms. The first that were tested was Vietnam combat veterans with memory problems due to PTSD. An MRI was used and it was found to have eight percent decreased in the right hippocampus.(Figure 3) The right hippocampus is associated with short-term memory loss. The same results were found when it was tested on victims of childhood traumas. The hippocampal volume reduction is due to PTSD and isn’t due to other disorders as panic disorders or anxiety disorders.
Another study that was done was on the hippocampus and recalling memories. Its role is to connect and organize parts of memories like proper time, place, and context. The damaged hippocampus from stress of the childhood abuse is the result of distorted and fragmented of memories. A study of the medial prefrontal cortex was looked at of combat veterans with PTSD and combat veterans without PTSD. The study was also done on women with PTSD and women with a history of abuse but with no PTSD. When combat veterans PTSD symptoms were present there was a decreased blood flow to the medial prefrontal cortex, the combat veterans without PTSD this didn’t happen to them. There were similar results with the women (Bremner 2000).