Corticostriatal afferents can engage parvalbumin-expressing (PV+) interneurons to rapidly curtail the activity of striatal projection neurons (SPNs), thus shaping striatal output. Schemes of basal ganglia circuit dynamics generally consider striatal PV+ interneurons to be homogenous, despite considerable heterogeneity in both form and function. We demonstrate that the selective co-expression of another calcium-binding protein, secretagogin (Scgn), separates PV+ interneurons in rat and primate striatum into two topographically-, physiologically- and structurally-distinct cell populations. In rats, these two interneuron populations differed in their firing rates, patterns and relationships with cortical oscillations in vivo. Moreover, the axons of identified PV+/Scgn+ interneurons preferentially targeted the somata of SPNs of the so-called 'direct pathway', whereas PV+/Scgn- interneurons preferentially targeted 'indirect pathway' SPNs. These two populations of interneurons could therefore provide a substrate through which either of the striatal output pathways can be rapidly and selectively inhibited to subsequently mediate the expression of behavioral routines.
interneuron, mouse, neuroscience, parvalbumin, rat, rhesus macaque, secretagogin, striatum, Animals, Axons, Basal Ganglia, Calcium-Binding Proteins, Corpus Striatum, Female, Interneurons, Macaca mulatta, Male, Mice, Mice, Inbred C57BL, Neostriatum, Neural Pathways, Neurons, Parvalbumins, Rats, Rats, Sprague-Dawley, Secretagogins