May 7, 2007

Subtle brain changes after trauma exposure

A new study highlights how easily a traumatic incident can alter brain functioning, and how long that change can last.

The researchers studied people who had been close to the World Trade Center on 9/11. Four years after the attack, people who were within 1.5 miles of the disaster still showed greater activation of their amygdalas – the region of the brain that controls our fight-or-flight instincts – than a control group who had been further away.

Participants were shown pictures of either calm or fearful faces while their amygdala activation was measured through a functional magnetic resonance imaging (fMRI) procedure. Those who were close to the WTC on 9/11 showed greater amygdala activation to fearful faces.

The results suggest that exposure to a single traumatic event may produce long-term brain changes that cause even healthy-appearing people to react more fearfully to everyday events.

The article, by Barbara Ganzel of Cornell University and colleagues, is available from the American Psychological Association at