Lexi Zhou L&S Sciences
Dopamine Modulation of Striatal Pathways in Choice Rejection
The Striatum plays a critical role in decision making and action outcome evaluation. It is primarily composed of two distinct pathwaysdirect and indirect that receive excitatory inputs from the cortex and the thalamus and are differentially modulated by dopamine signals from the midbrain. There has been a wealth of experimental and theoretical work on how the dichotomy of these striatal pathways mediates choice selection. The classic go/no-go model proposes that these pathways play discrete roles in choice selection, with the direct pathway fires to select a rewarding option and the indirect pathway fires to reject the rest. However, predictions made by this model are at odds with empirical findings. More recent studies show that these striatal pathways encode opposite value variables and are co-activated during choice selection, suggesting that they play opponent rather than independent roles in choice rejection. Using a serial decision-making task that isolates choice rejection and selection, my project leverages the lateralized nature of the striatum to experimentally demonstrate this new model. I will be looking at the relative activities of these striatal pathways in both hemispheres to test how they coordinate to generate decisions. I will also record the corresponding dopamine dynamics to see if it relates to the values of opposite choices and how it modulates the striatal pathways to regulate choice selection.