Afferent connections to the ventral striatum from the medial prefrontal cortex (area 25) and the thalamic nuclei in the macaque monkey.

The ventral striatal inputs in the macaque monkey were studied in relation to the connections from the orbitofrontal cortex, focusing on the infralimbic area (IL or area 25), thalamic nuclei and the vagal-solitary nuclear complex (NTS-X). The IL projects to more restricted parts of the ventral striatum (shell and core of nucleus accumbens, Acb; ventricular margin of caudate nucleus, CN), whereas the striatal projections of the prelimbic area (PL) are more extended than those of IL. The dorsal midline nuclei project densley to area 13, agranular insular cortex (Ia), and Acb. The nucleus ventralis anterior pars magnocellularis (VAmc) projects to the IL, perigenual area and to the region of CN between the limbic and association striatum with partial overlapping, and seems to play a role as an interface between the limbic and motor systems. The distribution pattern of retrogradely labeled neurons was similar in the midline-intralaminar thalamic nuclei following injections in the IL and ventral striatum.