Post-traumatic stress disorder
From WikiCover
Announced July 26, 2007, the first study to examine brain activity patterns in severely traumatized children showed their brains function differently than those of healthy children, say researchers at the Stanford University School of Medicine and Lucile Packard Children's Hospital.
The study hints at the biological underpinnings of the disorder called PTSD, or post-traumatic stress disorder. It also provides a valuable benchmark with which to assess the effectiveness of potential therapies.
Some children with PTSD cut or burn themselves as a way of coping with their feelings. The researchers found that affected children who had also cut or otherwise injured themselves exhibited unique patterns of activation in a portion of the brain involved in the perception of pain and emotions.
It's not yet clear whether the brain differences are caused by the interpersonal trauma, such as abuse, experienced by the children or if pre-existing differences make some children more susceptible to developing PTSD after traumatic events than their more resilient peers.
The researchers used an experimental technique called functional magnetic resonance imaging, or fMRI, to compare brain activation patterns in sixteen children with symptoms of PTSD with the patterns seen in fourteen age- and gender-matched non-traumatized children as they performed a simple decision-making task. The fMRI analysis detects changes in blood flow and oxygenation that correlate with increased neuronal activity in different regions of the brain.
To conduct the test, study subjects were placed inside the fMRI machine - a body-sized, narrow, hollow tube - and then asked to push a button each time a letter other than X flashed on a screen in front of them. Because Xs were introduced only after a string of non-Xs, the test is a good way to measure what's known as response inhibition, or a subject's ability to suppress the natural tendency to push the button as soon as any letter appears. Response inhibition is often difficult for children and adults with PTSD.
The researchers found that, although the two groups accomplished the task equally well, they used different parts of their brains to do so. The children with PTSD symptoms showed less activity than their non-traumatized peers in the left middle frontal cortex, an area known to be involved in response inhibition, and more activity in several other areas of the brain including a region involved in emotional awareness known as the insula.
People with PTSD often have trouble paying attention and responding appropriately to experimental tasks, perhaps due to heightened physiological arousal arising from their traumatic experience. As a result, many children with PTSD symptoms are diagnosed with attention-deficit hyperactivity disorder, or ADHD. But it's difficult to tell whether the two disorders are truly related, or if they simply have overlapping symptoms. Functional imaging like fMRI may allow researchers to finally solve the mystery. More importantly, it may help doctors devise better therapies.