NBIO Presents: Arif Hamid, PhD (University of Minnesota Twin Cities)

On the Principles of Dopamine Release in Dorsal Striatum

In this talk, I will present evidence that dopamine (DA) release across the striatum unfolds not as a global broadcast but as structured spatiotemporal waves that tailor reward signals to the computational specialties of distinct frontostriatal circuits. I will argue that these waves resolve a key spatiotemporal credit assignment problem by vector-weighting regional decision signals to facilitate a dynamic reprioritization of policy gating. I will outline our recent analysis of fundamental activational principles, demonstrating that DA fluctuations follow lawful, linear oscillatory dynamics captured by a generalized DA wave equation, and provide empirical evidence for circuit interactions that generate, propagate, and constrain these DA activity primitives. Together, our studies provide an empirically informed revision of an enduring “global broadcast” hypothesis about DA-RPE signals, clarifying the circuit and dynamical mechanisms underlying DA’s role in reinforcement learning.

Health Sciences G328 and Zoom