Research Unit 5159

Short Summary: Adaptive behaviour requires learning which actions lead to desired outcomes and updating these preferences when the world changes.  Reinforcement learning has provided an influential account of how this works in the brain, with reward prediction errors (RPEs), putatively conveyed via dopamine release, updating estimates of the values of states and/or actions.  However, the role dopamine plays in shaping adaptive behaviour remains contentious.  One reason for this is that it is increasingly clear that an ability to infer statistical relationships and hidden states of the world also plays an important role in shaping adaptive behaviour.  Intriguingly, brain recordings have shown that not only prefrontal cortex but also the dopamine system can reflect knowledge of such hidden states.  Additionally, dopamine might also represent actions and reward information beyond canonical RPE signals.  Here, I will present work from mice performing flexible reward-guided decision making tasks showing that dopamine indeed can convey a rich array of signals across different timescales and striatal regions about reward updates, actions taken, and the recent reward rates.  Nonetheless, while reward consistently shapes dopamine signalling, the influence of reward over adaptive choice goes beyond what is conveyed simply through dopamine.