Ventromedial Prefrontal Cortex and Its Role in PTSD

According to the Nebraska Department of Veteran's Affair, approximately 30% of those who serve in the military will experience posttraumatic stress disorder (PTSD). Not only that, those with PTSD tend to have anxiety, are more likely to exhibit substance abuse, more likely to be less social, and more likely to have stress which causes depression and results in a higher risk of suicide. It is a debilitating mental illness that encompasses many emotional aspects, but the most prominent of them all is fear. Fear is important, in an evolutionary aspect, because it stresses our body to heighten our senses and causes changes to it so it can respond by running or fighting. However, fear only comes when our life is in danger or when we are experiencing a traumatic event. With PTSD, it seems that the fear and stress stays when there is no danger or trauma.

The brain anatomy of those with PTSD differ from normal healthy people, especially in the ventromedial prefrontal cortex (vmPFC), amygdala, and hippocampus. Those with PTSD have a smaller hippocampus (link in distinguishing past and present memories), smaller vm(PFC) (responsible for regulating negative emotions in the amygdala), and a hyperactivity in the amygdala (responsible for emotions). With PTSD, the changes in the vmPFC, which may be caused by chemical changes due to stress, causes a failure in extinction of fear. A study by Koenings and his colleagues has shown that the vmPFC is indeed associated with inhibition of the amygdala illustrating that when examining individuals with vmPFC damage and their resulting anxiety and other negative affect.

A recent study has been published by researchers in Uppsala University are postulating how serotonin and substance P. may be involved in PTSD that cause these changes in the brain. According to them, their study “shows that it is the imbalance between the two signaling systems which determines the severity of the symptoms suffered by the individual […] Others have previously speculated that the biological basis of psychiatric disorders such as PTSD includes a shift in the balance between different signaling systems in the brain but none have yet proved it.” Though there is no cure, PTSD can be treated to help diminish the effect of PTSD through psychotherapy and certain drugs.

Sources

Motzkin, Julian c., Carissa L. Philippi, Richard C. Wolf, Mustafa K. Baskaya, and Michael Koenigs. Ventromedial Prefrontal Cortex Is Critical for the Regulation of Amygdala Activity in Humans. Rep. N.p.: Biological Psychiatry, 2015. Print.

"Post-Traumatic Stress Disorder." NIMH RSS. N.p., n.d. Web. 10 Dec. 2015.

"Post Traumatic Stress Disorder." Post Traumatic Stress Disorder. N.p., n.d. Web. 10 Dec. 2015.

Uppsala University. "Posttraumatic stress disorder reveals an imbalance between signalling systems in the brain." ScienceDaily. ScienceDaily, 1 December 2015.

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