It was generally accepted that dopamine receptors D1 (D1R)- and D2 (D2R)-expressing neurons are homogeneously and randomly distributed throughout the striatum. However, in reporter transgenic mice, the specific subregions of the caudal lateral striatum have been reported: the D1R-poor zone, in which D2R-expressing neurons are predominant, and the D2R-poor zone, in which D1R-expressing neurons are predominant. The present study demonstrated the presence of these distinct subregions not only in rodents but also in marmosets using endogenous dopamine receptors. We also showed that direct pathway medium spiny neurons in these distinct subregions preferentially project to parvalbumin-positive GABAergic neurons in the dorsal part of the substantia nigra pars lateralis. / 博士(理学) / Doctor of Philosophy in Science / 同志社大学 / Doshisha University