Neostriatal projections from individual cortical fields conform to histochemically distinct striatal compartments in the rat.

A number of recent studies have demonstrated two chemically distinct compartments in the neostriatum: opiate receptor-rich patches and a surrounding matrix. Using axonal transport and receptor localization techniques in the rat brain, we have found that striatal projections from architectonically distinct cortical fields conform to this compartmentalized plan. The prelimbic cortex has bilateral projections that concentrate within the striatal patches. In contrast, the agranular motor cortex and cingulate cortex have bilateral projections to the matrix, while the somatic sensory cortex and visual cortex have ipsilateral matrix projections. Each matrix input occupies a characteristic striatal district. The projection to the patches distributes prelimbic input throughout the striatum, which may allow for prelimbic interactions with input from all other cortical areas.