Proposed encoding of VLS MSNs Proposed encoding of VLS MSNs. Schematic illustration of basal ganglia circuitry (Kupchik et al., 2015) and proposed VLS MSN encoding. Proposed encoding of VLS MSNs. Schematic illustration of basal ganglia circuitry (Kupchik et al., 2015) and proposed VLS MSN encoding. Red represents unique connections (VLS D1-MSNs to VP, output from the VP). VLS D1-MSN to VM pathway encodes action sustainment (red shading), whereas VLS D1- and D2-MSN to VP pathway encodes action initiation (blue-shading). Akiyo Natsubori et al. J. Neurosci. 2017;37:2723-2733 ©2017 by Society for Neuroscience