Arif Hamid, Ph.D.
Research in the lab is focused on understanding how the neurotransmitter dopamine modulates the Cortico-Basal Ganglia-Thalamic circuitry in the service of learning from, planning, preparing, and executing adaptive and flexible behaviors. Though broadly interested in various nodes within this circuit and multiple levels of analysis, the approach in the lab is concentrated on providing a formal computational analysis of circuit mechanisms (anatomical and physiological properties) that implement specific operations and become leveraged during behavioral demands. To this end, we use carefully designed behavioral tasks in rodents (and an array of methods for measurement and manipulation of neural dynamics) to test precise predictions from competing models and iteratively refine our theoretical grasp on precisely how biological agents come to flexibly interact with their environment.
Our previous contributions have reported novel empirical findings (including dopamine midbrain spiking-vs-forebrain release dissociation (Hamid et. al., 2016, NatureNeuro, Mohebi et. al., 2019, Nature) and striatal dopamine waves in dorsal striatum (Hamid et. al., 2021 Cell)) that have significantly (re)shaped formalizations of dopamine’s role in Reinforcement Learning and agency learning. The lab seeks to build on this trajectory to make deep contributions that integrate experimental findings into multilevel neurocomputational models for tandem and cyclical advances in the simulated and empirical understanding of brain mechanisms for valuation, selection, planning, and execution of behavioral goals.
- Biol Psychiatry. 2022 Sep 15;92(6):514-522. Etiopathogenic models of psychosis spectrum illnesses must resolve four key features.
- Cell. 2021 May 13;184(10):2733-2749.e16. Wave-like dopamine dynamics as a mechanism for spatiotemporal credit assignment.
- Zacharoff LA, Hamid AA, Engeland WC, Dubinsky JM, Abnormal recovery from acute stress in Huntingtons Disease mice. 2021. bioRxiv 2021.07.21.453245;
- Hamid AA. Dopaminergic specializations for flexible behavioral control: Linking levels of analysis and functional architectures. Curr Opin Behav Sci. 2021;41:131-136.
- Hamid AA, Frank MJ, Moore CI. Dopamine waves as a mechanism of spatiotemporal credit assignment. Cell. 2021;184:2733-2749.
- Mohebi A, Pettibone JR, Hamid AA, Wong JM, Patriarchi T, Tian L, Kennedy R, Berke JD. Dissociable dopamine dynamics for learning and motivation. Nature. 2019 Jun;570(7759):65-70.
- Hamid AA, Pettibone J, Mabrouk O, Hetrick V, Schmidt S, Vanderweele CM, Kennedy RT, Aragona BJ, And Berke JD. Mesolimbic dopamine signals the value of work. Nat Neurosci. 2016 Jan;19(1):117-126.