Striatal cell-type specific stability and reorganization underlying agency and habit.

Adaptive decision making requires agency, knowledge that actions produce particular outcomes. For well-practiced routines, agency is relinquished in favor of habit. Here, we asked how dorsomedial striatum D1 and D2/A2A neurons contribute to agency and habit. We imaged calcium activity of these neurons as mice learned to lever press with agency and formed habits with overtraining. Whereas many D1 neurons stably encoded actions throughout learning and developed encoding of reward outcomes, A2A neurons reorganized their encoding of actions from initial action-outcome learning to habit formation. Chemogenetic manipulations indicated that both D1 and A2A neurons support action-outcome learning, but only D1 neurons enable the use of such agency for adaptive, goal-directed decision making. These data reveal coordinated dorsomedial striatum D1 and A2A function for the development of agency, cell-type specific stability and reorganization underlying agency and habit, and important insights into the neuronal circuits of how we learn and decide.