A hippocampus-accumbens code guides goal-directed appetitive behavior

Neurons in dorsal hippocampus (dHPC) encode a rich repertoire of task-relevant environmental features, while downstream regions such as the nucleus accumbens (NAc) translate this information into task-adaptive behaviors. Yet, the contents of this information stream and their acute role in behavior remain largely unknown. Here, we used in vivo dual-color two-photon imaging to simultaneously record from both large numbers of hippocampal neurons and an identified subpopulation of NAc-projecting neurons during goal-directed navigation towards a hidden reward zone. We found that NAc-projecting neurons contain enriched spatial information and enhanced representations of non-spatial task-relevant behaviors such as deceleration and appetitive licking, both of which could be elicited by optogenetic activation of dHPC terminals in NAc. A generalized linear model revealed enhanced conjunctive coding in NAc-projecting dHPC neurons, improving the identification of the reward zone. We propose that dHPC routes specific reward-related spatial and behavioral state information to guide NAc action selection.