parallel and segregated cortico-basal ganglia circuits. However, when terminals from various cortical areas are examined closely, it clearly demonstrates extensive convergence of inputs from different functional regions. This actually creates a complex interface between inputs from functionally distinct regions. Indeed, each cortical region, while projecting topographically to the striatum, does not maintain the narrow funneling that would be required to “fit” a large cortex into a far smaller striatal volume. For example, the volume occupied by the collective dense terminal fields from the ventromedial PFC (vmPFC), dorsal anterior cingulate cortex (dACC), and orbitofrontal cortex (OFC) is approximately 22% of the striatum, a larger cortical input than would be predicted by the relative cortical volume of these areas.14
