Distinct dynamics and intrinsic properties in ventral tegmental area populations mediate reward association and motivation

Ventral tegmental area (VTA) dopamine neurons regulate reward-related associative learning and reward-driven motivated behaviors, but how these processes are coordinated by distinct VTA neuronal subpopulations remains unresolved. Here, we compare the contribution of two primarily dopaminergic and largely non-overlapping VTA subpopulations, all VTA dopamine neurons and VTA GABAergic neurons of the mouse midbrain, to these processes. We find that the dopamine subpopulation that projects to the nucleus accumbens (NAc) core preferentially encodes reward-predictive cues and prediction errors. In contrast, the subpopulation that projects to the NAc shell preferentially encodes goal-directed actions and relative reward anticipation. VTA GABA neuron activity strongly contrasts VTA dopamine population activity and preferentially encodes reward outcome and retrieval. Electrophysiology, targeted optogenetics, and whole-brain input mapping reveal multiple convergent sources that contribute to the heterogeneity among VTA dopamine subpopulations that likely underlies their distinct encoding of reward-related associations and motivation that defines their functions in these contexts. [Display omitted] •Differential encoding of task-specific variables by dopamine subpopulations and GABA neurons•Differential encoding of motivated responses by dopamine subpopulations and GABA neurons•Dopamine subpopulations have different intrinsic properties and connectivity Elum et al. demonstrate that subpopulations of dopamine neurons and GABA neurons of the ventral tegmental area differentially encode task-specific variables during reinforcement learning and motivation. They further demonstrate that the distinct functions of dopamine subpopulations and their encoding of reward-related information are related to differences in intrinsic excitability and connectivity.