Dopamine regulation of action initiation and self-control (360G-Wellcome-202831_Z_16_Z)

Dopamine has long been associated with value-guided decision-making, but its precise contribution has remained elusive. One prominent theory elegantly relates the phasic activity of dopamine cell bodies to a prediction error term used in reinforcement learning to represent and update expectations of reward. However, another argues that the functional role of dopamine transmission in terminal fields is to motivate and energise responding. My recent work plots a path to reconcile these perspectives by demonstrating that dopamine release only encodes prediction errors if and when a reward-seeking action is appropriately initiated. Therefore, phasic mesolimbic dopamine release signals the value of action over inaction. My programme will use a combination of complex behavioural tasks and state-of-the-art techniques (fast-scan cyclic voltammetry, optogenetic stimulation, chemogenetic inactivation) to test: (i) whether these signals causally promote actions to be taken, even when actions should be withheld, (ii) what networks are involved in regulating mesolimbic dopamine release in situations when actions should be withheld, and (iii) how mesolimbic dopamine release influences a key foraging decision about whether to act to engage with a presented opportunity. Together, these studies will provide fundamental new insights into the relationship between dopamine release, value and action.