While the topographic organization of corticostriatal projections is well documented, there is increasing evidence for regions of interface between terminals from different cortical areas, suggesting functional integration. For example, early studies showed that corticostriatal terminals from sensory and motor cortex converge within the striatum.69 Here, axons from each area synapse onto single fast-spiking GABAergic interneurons. Interestingly, these interneurons are more responsive to cortical input than the MSNs.104-106 This suggests a potentially critical role for interneurons in integrating information from different cortical areas before passing that information on to the medium spiny projection cells.
