The researchers said their findings suggest why people subject to traumatic events may be trapped in a cycle of emotion and recall that aggravates post-traumatic stress disorder (PTSD). They said their findings also suggest why therapies in which people relive such memories and reshape perspective to make it less traumatic can help people cope with such memories.

The paper by Florin Dolcos, Kevin LaBar and Roberto Cabeza, was published online February 9, 2005, in the Proceedings of the National Academy of Sciences. The researchers are in Duke University's Center for Cognitive Neuroscience, Department of Psychological and Brain Sciences, and Brain Imaging and Analysis Center. Their work was sponsored by the National Institutes of Health and the National Science Foundation.

"This study is the first to really test recall of emotional memories after a long time period," said Cabeza. "Previous studies had only allowed a short time interval, for example minutes, between encoding of the memory and retrieval. Hence, they could not distinguish between the process called consolidation -- in which memories are being established -- and retrieval. Also, they did not distinguish between true recollection of a memory and a vague familiarity. In memory studies, it's very important to distinguish between these two phenomena," he said.

In their study, the researchers showed volunteer subjects images that were pleasant, unpleasant or neutral while their brains were being scanned with functional magnetic resonance imaging (fMRI). In this widely used technique, harmless magnetic fields and radio waves are used to image blood flow in regions of the b
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Contact: Dennis Meredith
dennis.meredith@duke.edu
919-681-8054
Duke University
8-Mar-2005