Parvalbumin Interneurons Determine Emotional Valence Through Modulating Accumbal Output Pathways.

Parvalbumin (PV) expressing GABAergic interneurons provide large source of GABA to spiny projection neurons (SPNs) in the striatum. However, the roles of PV interneurons in the regulation of SPNs in the ventral striatum and emotional states are largely unknown. Here, we investigated whether stimulation of ventral striatal (accumbal) PV interneurons would drive emotional valence in mice. We found that during conditioned place preference (CPP) training, activation of accumbal PV interneurons evoked place preference while suppressing them resulted in conditioned place aversion (CPA). Activation of PV interneurons during place conditioning increased expression in SPNs in the direct pathway (dSPNs) and impaired lithium chloride-induced CPA. Activation of dSPNs and SPNs in the indirect pathway (iSPNs) induced CPP and CPA, respectively; conversely, suppression of dSPNs or iSPNs induced CPA or CPP. In addition, activation or suppression of calretinin-expressing (CR) GABAergic interneurons did not induce place preference or aversion. These data suggest that PV interneurons can bidirectionally determine the emotional valence through their regulation of accumbal SPN activities and raise the possibility that manipulation of PV interneuron activity may have the potential to alter emotional valence and treat related mental disorders.