The prefrontal cortex has extensive connectivity to cortical and subcortical circuits that may underlie its importance in cognitive functions and modulation of limbic activity .The main subcortical structures participating in these circuits are the basal ganglia, thalamus, hypothalamus, brainstem, and the white matter tracts that connect these structures among themselves and to the cerebral cortex . A limbic-thalamic-cortical circuit consisting of the amygdala, the medio-dorsal nucleus of the thalamus, and the medial and ventro-lateral prefrontal cortex, and a limbic-striato-pallidal-thalamic circuit comprising the striatum, the ventral pallidum, and the components of the other circuit are the main neuro-anatomic circuits that have been proposed to participate in the pathophysiology of mood disorders.