Subthalamic Nucleus dynamically encodes reward value and cognitive flexibility

STN calcium activity tracks reward-predictive cues and remaps after reversal, with chemogenetic STN inhibition impairing cue discrimination and delaying reversal learning in Pavlovian tasks.

• Why it matters: It remains unclear how the STN encodes learned reward associations and updates them when contingencies change, limiting understanding of its role in cognitive flexibility.
• What they did: Using fibre photometry calcium imaging during established Pavlovian conditioning, the STN showed responses to reward predictive cue and reward delivery but not unrewarded cues; after reversal, activity remapped to the newly rewarded cue. Chemogenetic inhibition impaired cue discrimination, delayed reversal learning, and disrupted outcome-specific Pavlovian-to-instrumental transfer.
• The result: These results show STN activity is required for flexible updating of learned reward associations and goal-directed behaviour, establishing the STN as a dynamic integrative hub for cognitive flexibility.