Dopamine supports reward prediction to constrain reward seeking
Reward-predictive cues trigger dopamine release in the nucleus accumbens core (NAc). This signal has long been thought to mediate motivation. However, understanding of dopamine function is complicated by the fact that reward cues not only motivate reward pursuit, but also enable the reward predictions that shape how reward is pursued. Thus, here we used dopamine sensor fiber photometry, cell-type and pathway-specific optogenetic inhibition, Pavlovian cue-reward conditioning, and test of cue-induced reward-pursuit strategy in male and female rats, to ask how cue-evoked phasic dopamine release supports reward pursuit. Cues that predicted imminent reward with high probability triggered a large NAc dopamine response and checking for the expected reward in the delivery location, rather than exploratory reward seeking. Cues that predicted reward with low probability elicited less dopamine and biased towards motivation to seek, rather than check for reward. Cue-evoked dopamine inversely related to and predicted reward seeking. Correspondingly, yet surprisingly, inhibition of cue-evoked NAc dopamine increased reward-seeking motivation and decreased reward checking. Thus, cue-evoked NAc dopamine is positively modulated by high imminent reward prediction to constrain exploratory reward-seeking motivation in favor of a more focal reward-checking strategy. These data advance understanding of dopamine function by indicating dopamine does not simply promote reward-seeking motivation, but rather supports reward predictions to shape adaptive reward pursuit strategy.