Prefrontal lobe-substantia nigra projection in human cerebrum

A PF-SN projection in the human cerebral neocortex was studied and the following results obtained. The PF-SN projection tract originates mainly from areas 9 and 10 and probably also from areas 46 and 47, and passes through the ipsilateral frontopontine tract. The main projecting area is the intermedial region of the pars compacta in the SN in a medio-lateral direction. The PF-SN projection fibers exist in quantities, possibly equal to those of the striatum-SN projection fibers. Fibers projecting from areas of the cerebral neocortex other than the PF to the pars compacta in the SN are likely to be absent.