Tuesday, September 13, 2005

Brain Size May Prevent Anxiety

A little technical, but this article suggests that those with a larger brain structure in the front of the brain may have some resiliency to developing anxiety disorders. It will be interesting to see if psychotherapy or psychoeducational approaches can lead to an increase in the size of this area of the brain, creating some immunity to anxiety. Here is part of the article, what do you think?

Size of Brain Structure Could Signal Vulnerability to Anxiety Disorders

By: Massachusetts General Hospital on Jul 23 2005 16:52:05

Anxiety Disorders

The ventromedial prefrontal cortex (vmPFC) area appears smaller in those that continue to react to images associated with discomfort

The size of a particular structure in the brain may be associated with the ability to recover emotionally from traumatic events. A new study by researchers from Massachusetts General Hospital (MGH) finds that an area called the ventromedial prefrontal cortex is thicker in volunteers who appear better able to modify their anxious response to memories of discomfort. The report will appear in the Proceedings of the National Academy of Science and has received early online release on the PNAS website.

"We've always wondered why some people who are exposed to traumatic experiences go on to develop anxiety disorders like post-traumatic stress disorder and others do not," says Mohammed Milad, PhD, a research fellow in the MGH Department of Psychiatry, the study's lead author. "We think this study provides some potential answers."

In the classical model of conditioned fear, individuals respond with physical and emotional distress to situations that bring back memories of traumatic events. Such responses are normal and usually diminish over time, as those situations are repeated without unpleasant occurrences. But some people continue to respond with what can be overwhelming fear and may develop post-traumatic stress disorder (PTSD).

For example, it would not be unusual for a soldier who experienced a traumatic battlefield situation to become distressed when hearing noises that bring back those memories, such as the sound of a helicopter. Most commonly, repeated exposure to such sounds without additional trauma reduces or extinguishes the fearful response - a phenomenon called "extinction memory." But some individuals continue to experience anxiety, along with other symptoms characteristic of PTSD, when hearing the sounds.

Prior studies in animals have suggested that the ventromedial prefrontal cortex (vmPFC), an area on the lower surface of the brain, may be involved in extinction memory. The vmPFC may help to quell potential fears by inhibiting the activity of the amygdala, an area known to be involved with fear. The current study was designed to see if the structure of the vmPFC is related to the ability to modify response to an unpleasant memory.


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