Differential coding of reward and movement information in the striatal direct and indirect pathways

Abstract

To better understand striatal neural processes underlying reward-based learning and movement control, we examined the responses of D1 and D2 medium spiny neurons (MSNs) in the -dorsomedial striatum of mice performing a probabilistic Pavlovian conditioning task. These neurons, which are components of the direct and indirect pathways, respectively, showed diverse arrays of reward- and tongue movement-related activity, but with quantitative differences. D1 and D2 MSNs tended to increase and decrease activity as a function of reward value, respectively, suggesting striatal value representation by relative activity levels between D1 and D2 MSNs. D1 MSNs increased activity more strongly than D2 MSNs in association with lick offset, suggesting the involvement of D1 MSNs in suppressing licking behavior. In addition, rapid responses to negative outcome and previous reward signals were stronger among D2 than D1 MSNs, suggesting stronger contributions of D2 MSNs to outcome-dependent behavioral adjustment. These findings provide new insights into striatal neural circuit operations underlying reward-based learning and movement control.