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Dopamine tone influences strategic learning in humans: a pharmacological PET study

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Jacinda Taggett¹ (jacinda.taggett@gmail.com), Nienhsuan Su^1,2, Julia Bertolero^1,2, Joshua Warren⁴, William Jagust¹, Andrew Kayser^1,2,3, Ming Hsu¹; ¹UC Berkeley, ²UC San Francisco, ³San Francisco VA Health Care System, ⁴Yale University

Competitive social interactions are critical in determining access to resources and status. Previous work has demonstrated that competitive decisions require agents to behave strategically, learning not only about the reward structure of their environment but also about the actions of others competing for those same rewards. While these studies have begun to reveal the behavioral and neural correlates of this form of social learning, its neurochemical bases, especially those related to dopaminergic functioning, have largely relied on indirect inferences. Here, we used a strategic learning framework that incorporates participants’ beliefs about others’ actions in order to model performance in a competitive social game, the patent race. Subjects performed the task twice in counterbalanced fashion, after receiving either the catechol-O-methyltransferase (COMT) inhibitor tolcapone, which enhances cortical dopamine tone, or placebo. In addition, we used 11-C raclopride PET to obtain measures of D2/3 receptor availability and dopamine release. We hypothesized that parameters sensitive to reward history and beliefs in competitive social learning would be similarly influenced by dopaminergic tone. Utilizing the experience-weighted attraction model to parameterize learning, we find that participants more strongly weigh recent outcomes on tolcapone versus placebo, and that this effect is enhanced in the context of greater baseline dopamine release. However, we see no main effects of baseline D2/3 receptor availability on the parameters for strategic learning. Together these results support models in which dopamine tone supports strategic social learning, and they suggest the importance of ongoing work to directly evaluate neuromodulatory influences on social function.

Topic Area: THINKING: Decision making