Brain trait fosters stress disorder
By Bruce Bower
Several studies have noted that an inner brain structure, the hippocampus, is unusually small in individuals who, after surviving extraordinary threats, experience flashbacks, nightmares, and other symptoms of post-traumatic stress disorder (PTSD). A new investigation, in the November Nature Neuroscience, indicates that some of these people possess an undersized hippocampus before they ever develop PTSD.
This finding challenges the theory that hormonal responses to traumatic events shrink the hippocampus, a brain area implicated in memory and in the learning of fear responses (SN: 6/3/95, p. 340).