Medium spiny neurons spontaneous activity reveal the discrete segregation of mouse dorsal striatum

Behavioural studies differentiate the rodent dorsal striatum (DS) into lateral and medial regions based on their particular roles; however, anatomical evidence suggest that it is a unified structure. To understand striatal dynamics and basal ganglia functions, it is essential to clarify the circuitry that supports this behavioural-based segregation. Here, we show that the mouse DS is made of two non-overlapping functional circuits divided by a sharp boundary. Combining in vivo optopatch-clamp and extracellular recordings of spontaneous activity, we demonstrate different coupling of lateral and medial striatum to the cortex together with an independent integration of the slow and fast oscillations, due to particular cortico-striatal connectivity and local properties of each region. Additionally, distinct properties between striatonigral and striatopallidal neurons were revealed along DS. These results demonstrate that the rodent DS is segregated in two neuronal circuits, in homology with the caudate and putamen nuclei of primates.