Striatal dopamine release tracks the relationship between actions and their consequences

The acquisition and performance of goal-directed actions has long been argued to depend on the integration of glutamatergic inputs to the posterior dorsomedial striatum (pDMS) under the modulatory influence of dopamine. Nevertheless, relatively little is known about the dynamics of striatal dopamine during goal-directed actions. To investigate this, we chronically recorded dopamine release in the pDMS as rats acquired two actions for distinct outcomes as these action-outcome associations were incremented and then subsequently degraded or reversed. We found that bilateral dopamine release scaled with action value, whereas the lateralized dopamine signal, i.e., the difference in dopamine release ipsilaterally and contralaterally to the direction of the goal-directed action, reflected the strength of the action-outcome association independently of changes in movement. Our results establish, therefore, that striatal dopamine activity during goal-directed action reflects both bilateral moment-to-moment changes in action value and the long-term action-outcome association.