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Study may show how PTSD changes the brain

A new study shows that brain circuitry may actually change for people diagnosed with post traumatic stress symptoms, according to researchers from Duke University and the Durham, N.C., Veterans Affairs Medical Center.

Beyond the symptoms most-associated with PTSD — nightmares, flashbacks and hyper-awareness — combat troops also often suffer from an inability to think clearly or remember things well, which makes performing basic daily tasks difficult. While these same symptoms have been connected to traumatic brain injuries as a result of amnesia and short-term memory loss, some researchers began to wonder if service members’ brains had reorganized themselves to respond immediately to potentially dangerous information. According to the study, printed in Psychiatry Research: Neuroimaging journal, all of a person’s attention goes to an immediate, life-or-death situation, rather than letting other information filter in.

In one study, several words related to trauma were printed in different color inks. The combat veterans took longer to name the colors than non-combat veterans did, possibly because the combat veterans’ brains registered the words’ meanings as too important to allow the color information to process.

So researchers decided to look at neuroimaging to see if the way a person processes tasks changes if he is exposed to an emotional stimulus. They worked with 26 veterans of the current conflicts in Iraq and Afghanistan who had a history of combat trauma.

To test their reactions, the researchers had the veterans look at photos of mutilations, burn victims, aimed guns, starving children, severed hands or dead bodies. They also showed them pictures of neutral photos, such as a picture of a square or apple. Two groups of veterans — those with high levels of symptoms and those with low — were asked to push the same button for both emotional and neutral photos, but push a different button for a specific neutral photo. All had longer reaction times, compared to nonveterans, to the pictures that were negative.

However, the people in the two groups processed the information at higher levels in different parts of their brains and at different rates. The researchers already knew that people without mental health disorders process tasks in the dorsal — the back — regions of the brain. But in this study, the veterans with higher levels of PTSD symptoms had less activity in the dorsal regions. Instead, researchers saw the most activity for people with high levels of PTSD in the middle frontal gyrus of the prefrontal cortex. That could mean that those with fewer symptoms paid more attention to the task of looking for the specific photo so they could push the correct button, while those with higher levels of symptoms concentrated more on the emotional content of the photos.

Lead author Jasmeet Pannu Hayes of Duke’s Brain Imaging and Analysis Center wrote that it may be possible to determine from neuroimaging whether someone is suffering from an inattention disorder.

According to military studies, one out of five soldiers and Marines has PTSD three to four months after they return home from deploying to Iraq or Afghanistan.