The final large C-BG-C circuit that we will discuss is the sensorimotor circuit. As the name implies, this circuit includes the primary sensory and motor neocortices, along with some secondary regions such as supplementary motor areas (e.g. mouse M2 cortex). These cortical regions project into the dorsolateral striatum (DLS) in rodents (roughly equivalent to the putamen nucleus in primates). Indeed, there are several subcircuits within the corticostriatal sensorimotor projections that roughly correspond to different body parts, forming a very diffuse “humuncular” representation. No attempt will be made to differentiate these subcircuits in the present review. The intralaminar nuclei of the thalamus project to DLS, including several regions extending across the anterior-posterior extent of the thalamus. The dopaminergic DLS innervation comes mainly from the lateral portions of the SNc. The DLS MSNs innervate the lateral GPe, GPi and SNc, but there is also considerable overlap with regions receiving DMS input.
