Distinct Temporal Windows for Ventral Tegmental Area Dopamine Neurons are Required for Active Avoidance Learning.

Abstract

Ventral tegmental area (VTA) dopamine neurons play a central role in learning. Previous studies have shown that dopamine signaling is required for negative reinforcement and aversive instrumental learning, but whether this contribution is mediated by temporally distinct activity of dopaminergic neurons remains poorly understood. Here, using a two-way active avoidance paradigm, we monitored VTA dopamine neuron activity in animals that successfully acquired avoidance behavior and found that VTA dopamine neuron activity increased at two distinct time points, during the conditioned stimulus (CS) period and immediately after active avoidance. To test the functional significance of these signals, we chemogenetically inhibited VTA dopamine neurons. Global suppression of VTA dopamine neuron activity impaired avoidance learning. Furthermore, temporally restricted inhibition using optogenetics either during the CS period or immediately after successful avoidance was also sufficient to disrupt learning. We further mapped downstream projections of VTA dopamine neurons and monitored dopamine release in the basolateral amygdala (BLA) and nucleus accumbens (NAc), revealing that dopamine release in these regions was differentially aligned with cue-related and post-avoidance components of VTA dopamine neuron activity. Together, these findings suggest that VTA dopamine neurons support aversive instrumental learning through temporally distinct activity patterns that are accompanied by region-specific dopamine release dynamics in the BLA and NAc.