Science/Tech

PTSD Combat Veterans' 'Fear Circuitry' In Brains Always On High Alert

'Fear Circuitry' in Combat Veterans' Brains Always on High Alert with PTSD
Researchers have found the parts of the brain associated with PTSD, and learned what kind of activity sets of the disorder. Sergeant William Greer, United

Post-traumatic stress disorder (PTSD) has long been known to have lasting behavioral and emotional effects on soldiers long after they leave the combat zone. But what happens to physically to the brain of a combat veterans with PTSD is gaining more attention, including that of researchers at New York University's School of Medicine.

Their research, which was presented today at the annual meeting of the American Psychiatry Association in San Francisco, showed that PTSD physically manifests within certain regions of the brain, even when combat veterans aren't engaged in cognitive or emotional tasks and face no external threats.

"It is critical to have an objective test to confirm PTSD diagnosis as self-reports can be unreliable," said co-author Dr. Charles Marmar, chair of NYU Langone's Department of Psychiatry.

The study, which was led by Xiaodan Yan, a research fellow at NYU School of Medicine, analyzed "spontaneous" or "resting" brain activity in 104 combat veterans — 52 with PTSD and 52 without — from the Iraq and Afghanistan wars using functional MRI, which measures blood-oxygen levels in the brain. They found that the PTSD group had a significantly higher activity in the amygdala, the part of the brain that controls "fear circuitry" and anxious emotions. In the same group, they also found elevated activity in the anterior insula, the part of the brain that regulates sensitivity to pain and negative emotions.

Possibly the most intriguing finding was that the PTSD group had lower levels of activity in the precuneus, a region of the brain tucked between the two hemispheres that helps integrate information from the past and future, especially when a person's mind wanders. These lower levels have been connected to more severe bouts of re-experiencing traumas over and over through flashbacks, nightmares, and frightening thoughts.

This information is extremely important in developing treatments for PTSD plaguing veterans from the experiences of war. According to the release, of the 1.7 million soldiers who served in Iraq or Afghanistan, 20 percent have PTSD. Suicide is also the second leading cause of death among military personnel, according to RAND Corp., and more soldiers committed suicide in 2012 than the number of soldiers killed in combat in Afghanistan that year.

The results of this study were published in Neuroscience Letters.

Source: X Yan, A Brown, C Marmar, et al. Spontaneous brain activity in combat related PTSD. Neuroscience Letters. May 2013.

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