Increased amygdala activation during mania: A functional magnetic resonance imaging study

Objective: This study sought to investigate neural activity in the amygdala during episodes of mania. Method: Nine manic subjects and nine healthy comparison subjects underwent functional magnetic resonance imaging ( fMRI) while performing a neuropsychological paradigm known to activate the amygdala. Subjects viewed faces displaying affect ( experimental task) and geometric forms (control task) and matched them to one of two simultaneously presented similar images. Results: Manic subjects had significantly increased activation in the left amygdala and reduced bilateral activation in the lateral orbitofrontal cortex relative to the comparison subjects. Conclusions: Increased activation in the amygdala and decreased activation in the orbitofrontal cortex may represent disruption of a specific neuroanatomic circuit involved in mania. These brain regions may be implicated in disorders involving regulation of affect.