retrogradely labeled neurons are also present within the substantia nigra of these same tissue sections , where they are most abundant within the pars compacta , but lesser numbers of labeled neurons are also present within the pars reticularis , pars lateralis , retrorubral area , and ventral tegmental area on the ipsilateral side , and all of these same subdivisions of the substantia nigra on the contralateral side .
C0038590
substantia nigra
C0175412
pars compacta