Washington: Researchers at NYU School of Medicine have shown that the effects of trauma persist in certain brain regions even when veterans of combat are not engaged in cognitive or emotional tasks, and face no immediate external threats.
The results shed light on which areas of the brain provoke traumatic symptoms and represent a critical step toward better diagnostics and treatments for post-traumatic stress disorder (PTSD).
A chronic condition that develops after trauma, PTSD can plague victims with disturbing memories, flashbacks, nightmares and emotional instability.
The study, led by Xiaodan Yan, a research fellow at NYU School of Medicine, examined "spontaneous" or "resting" brain activity in 104 veterans of combat from the Iraq and Afghanistan wars using functional MRI, which measures blood-oxygen levels in the brain.
The researchers found that spontaneous 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.
The PTSD group also showed elevated brain activity in the anterior insula, a brain region that regulates sensitivity to pain and negative emotions.
Moreover, the PTSD group had lower activity in the precuneus, a structure tucked between the brain`s two hemispheres that helps integrate information from the past and future, especially when the mind is wandering or disengaged from active thought. Decreased activity in the precuneus correlates with more severe "re-experiencing" symptoms-that is, when victims re-experience trauma over and over again through flashbacks, nightmares and frightening thoughts.
The result of the study has been published in Neuroscience Letters.