Figure 6.

Parallel basal ganglia circuits for voluntary and automatic behaviour. Receiving inputs from different cortical areas, caudate head (CDh) and caudate tail (CDt) have separate downstream circuits, both targeting superior colliculus (SC). Both circuits process object–value memory and learning, but do so under different conditions. These two learning mechanisms lead to different outcomes, namely voluntary and automatic behaviour. Separate groups of dopamine neurons may contribute to the different kinds of memory processing. GPe(r) = rostral part of globus pallidus external segment; GPe(c) = caudal part of globus pallidus external segment.