The Amygdala in Post-Traumatic Stress Disorder

Over the past decade, neuroimaging studies have yielded important insights into the function of the amygdala in post-traumatic stress disorder (PTSD). The results of these studies are presented here. Because neurocircuitry models of PTSD also emphasize the role of the medial prefrontal cortex, findings regarding that brain region are discussed as well. The reviewed studies suggest that (1) the amygdala is hyperresponsive to both trauma-related and unrelated stimuli in PTSD, (2) amygdala activation is positively correlated with PTSD symptom severity and, in some studies, inversely correlated with medial prefrontal cortex function, (3) symptom reduction after treatment is associated with decreased amygdala activation and increased medial prefrontal cortex activation, and (4) medial prefrontal cortex is hyporesponsive in PTSD, perhaps reflecting diminished inhibitory control over the amygdala. All of this information suggests that the amygdala and medial prefrontal cortex play important roles in the pathogenesis or maintenance of this disorder. Limitations and future directions of this research are discussed.