The basal ganglia play key roles in adaptive behaviors guided by reward and punishment. However, despite accumulating knowledge, few studies have tested how heterogeneous signals in the basal ganglia are organized and coordinated for goal-directed behavior. In this study, we investigated neuronal signals of the direct and indirect pathways of the basal ganglia as rats performed a lever push/pull task for a probabilistic reward. In the dorsomedial striatum, we found that optogenetically and electrophysiologically identified direct pathway neurons encoded reward outcomes, whereas indirect pathway neurons encoded no-reward outcome and next-action selection. Outcome coding occurred in association with the chosen action. In support of pathway-specific neuronal coding, light activation induced a bias on repeat selection of the same action in the direct pathway, but on switch selection in the indirect pathway. Our data reveal the mechanisms underlying monitoring and updating of action selection for goal-directed behavior through basal ganglia circuits.
Keywords: action selection; antidromic activation; basal ganglia; decision making; direct and indirect pathway; dorsomedial striatum; optogenetics; outcome; punishment; reward.
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