A Functional Magnetic Resonance Imaging Study of Amygdala and Medial Prefrontal Cortex Responses to Overtly Presented Fearful Faces in Posttraumatic Stress Disorder

The present study explored amygdala hyperresponsivity for individuals with posttraumatic stress disorder (PTSD) using functional magnetic resonance imaging (fMRI). Blood oxygenation level-dependent (BOLD) signal responses were assessed for a sample of 26 participants (13 with PTSD; 13 without PTSD) as they watched fearful, happy and neutral facial expressions. fMRI data was analyzed with a statistical parametric mapping method.

Key Findings:

  • The PTSD group's amygdala response was heightened while medial prefrontal cortex responses were reduced when presented with fearful versus happy expressions.
  • For the PTSD group, BOLD signal changes in the amygdala had an inverse relationship with media prefrontal cortex signal changes. Severity of PTSD symptoms was also inversely related to BOLD changes in the medial prefrontal cortex.
  • As compared to the control group, the PTSD group had less of a habituation in the right amygdala to fearful versus happy responses over fMRI runs.