Anxious Youth Have Disturbed Brain Responses When Looking At Angry Faces
When looking at angry faces so quickly that they are hardly aware of seeing them, youth with generalized anxiety disorder (GAD) have unchecked activity in the brain’s fear center, say NIMH researchers. This disturbance is greater in those who are more severely anxious.
These findings were reported in an article in the May 2008 issue of the Archives of General Psychiatry by NIMH-funded investigator Christopher S. Monk, Ph.D, of the University of Michigan, and colleagues at the University of California, Los Angeles; University of Southampton, Southampton, UK; Georgia State University, Atlanta; and NIMH in Bethesda, Md.
The investigators used functional magnetic resonance imaging, a brain-scanning technique that shows increases in blood flow when regions of the brain become active, to study changes in the regions of the brain after the participants saw pictures of angry faces. These pictures were shown so quickly—only 17 thousandths of a second—that the participants hardly saw them. The participants included 17 children and adolescents with GAD and 12 who were healthy.
The scans showed that increased anxiety is associated with increased activation of the brain’s fear center, the amygdala. This almond-shaped structure, deep in the brain, triggers a fear or anxiety response, and alerts the rest of the brain that a threat is present.
Scientists believe that the amygdala is normally kept in check by the brain’s executive hub, the prefrontal cortex, which is located behind the eyes and the forehead. The scans showed that the executive hub’s control over the fear center is weakened in the anxious participants. The scans also showed that the executive hub has the least control in the most anxious participants.