Single-cell activity tracking reveals that orbitofrontal neurons acquire and maintain a long-term memory to guide behavioral adaptation

Learning to predict rewards based on environmental cues is essential for survival. The orbitofrontal cortex (OFC) contributes to such learning, by conveying reward-related information to brain areas such as the ventral tegmental area (VTA). Despite this, how cue-reward memory representations form in individual OFC neurons and are modified based on new information is unknown. To address this, using in vivo 2-photon calcium imaging in mice, we tracked the response evolution of thousands of OFC output neurons, including those projecting to VTA, through multiple days and stages of cue-reward learning. Collectively, we show that OFC contains several functional clusters of neurons distinctly encoding cue-reward memory representations, with only select responses routed downstream to VTA. Surprisingly, these representations were stably maintained by the same neurons even after extinction of the cue-reward pairing, and supported behavioral learning and memory. Thus, OFC neuronal activity represents a long-term cue-reward associative memory to support behavioral adaptation.