I guess I know why I like Labrador Retrievers so much--we both really enjoy everything life has to offer.
http://www.armytimes.com/news/2009/0...rauma_033009w/
Study holds clue to gauging trauma resiliency
By Kelly Kennedy - Staff writer
Posted : Tuesday Mar 31, 2009 10:22:46 EDT
A study may offer a tantalizing clue to identifying which service members may be particularly resilient to trauma and stress — and which ones may not be.
One of the symptoms of post-traumatic stress disorder is a “reduced capacity for reward” — meaning nothing seems exciting. Amusement park? Not interested. Beautiful day? Heavy sigh. Friday night date with the spouse? Please.
Researchers from the government’s National Institute for Mental Health in Bethesda, Md., and at Fort Bragg, N.C., wanted to see if those who have a “robust reward function” might be more resilient to stress — and if they could pick that up on a brain scan.
In the study, detailed in the journal Psychiatry Research: Neuroimaging, the researchers gathered 11 Special Forces soldiers at Fort Bragg who had been exposed to trauma but had not developed PTSD and took them to the National Institute for Mental Health to perform some tests alongside 11 civilians who had no symptoms of mental health issues and no history of experiencing trauma.
Both groups had similar IQ scores.
Each person performed a task on a computer: If a particular image popped up, they were to push a button as quickly as they could. But before each group of images, they were told the stakes:
For one group, if they pushed the button correctly, they would receive $5. For another group, they would lose $5 if they didn’t push the button correctly. For a third group, they would neither gain nor lose money if they pushed the button correctly.
While the men performed the tasks, researchers monitored their brain activity using digital imaging.
Researchers discovered that in the civilians, the right subgenual prefrontal cortex, which may be where the brain decides how outside input will affect mood, lit up more when the stakes were “you will receive $5” than when the stakes were “you will neither gain nor lose money,”
But in the Special Forces troops, the brain lit up the same way no matter what the stakes were. In other words, no matter what they were told, they got excited about everything.
The civilians also engaged the right nucleus accumbens — which monitors reward function and may be involved in laughing, pleasure, addiction and fear — more when they had more to gain.
But again, the Special Forces troops’ brains reacted the same no matter what the stakes.
Lead researcher Meena Vythilingam wrote that this could be a potential biomarker that the military might use to keep those who might not be as resilient out of high-stress jobs, while also quickly getting more susceptible troops to help if they experience trauma.
The researchers said more work needs to be done to see if the soldiers’ brains reacted differently because they had already been exposed to trauma or if they would have reacted the same before they were exposed.
And they don’t know yet if the soldiers’ reactions mean they have a higher or lower baseline of activity in those areas than the civilians do.
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