Abstract:
Five parallel anatomic circuits link regions of the frontal cortex
to the striatum, globus pallidus/substantia nigra, and thalamus. The
circuits originate in the supplementary motor area, frontal eye fields,
dorsolateral prefrontal region, lateral orbito-frontal area, and
anterior cingulate cortex. Open loop structures that provide input to or
receive output from specific circuits share functions, cytoarchitectural
features, and phylogenetic histories with the relevant circuits. The
circuits mediate motor and oculomotor function as well as executive
functions, socially responsive behavior, and motivation.
Neuropsychiatric disorders of frontal-subcortical circuits include
impaired executive function, disinhibition, and apathy; indicative mood
disorders include depression, mania, and lability. Transmitters,
modulators, receptor subtypes, and second messengers within the circuits
provide a chemoarchitecture that can inform pharmacotherapy