New research has found that the effects of post-traumatic stress disorder (PTSD) can persist even in the absence of stressful stimuli. Past research has focused on the fact that the brains of people with PTSD might over- or under-react when presented with stressful situations, but this study is the first to document how the brain manages stress during times of calm.
Researchers from the New York University School of Medicine sought to document what happens in the minds of people with PTSD when no external triggers are present. They worked with 104 veterans returning from Iraq and Afghanistan to examine both “spontaneous” and “resting” brain activity. The research team used a functional MRI, which measures the brain’s blood-oxygen levels.
After examining the veterans, they found that the subjects’ amygdalas—the part of the brain that deals with fear and anxiety—produced 52% more spontaneous brain activity in combat veterans with PTSD than the combat veterans who did not have PTSD. They also found that the veterans with PTSD exhibited elevated brain activity in the anterior insula, which regulates pain and negative emotions. Finally they also documented decreased activity in the precuneus—a part of the brain that is involved in episodic memory, visuospatial imagery, and the sense of self—which is correlated with increased severity of “re-experiencing” trauma.
One problem with diagnosing PTSD is that there is no objective test, but this research may lead to being able to establish concrete standards for what consists of PTSD.
PTSD is known to cause its sufferers recurring flashbacks, nightmares, and emotional instability. Many researchers have taken on the subject as of late because an estimated 20% of the 1.7 million veterans returning from Iraq and Afghanistan have PTSD. Furthermore, PTSD has been shown to increase suicide risk in veterans.
This study was published in the journal Neuroscience Letters.