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.