Frontal Striatal Systems and Dopamine in Normal and Pathological Behavior

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Our lab uses a combination of neurophysiology, pharmacology and imaging to understand how a set of brain areas composed of the amygdala, striatum, prefrontal cortex and dopamine underlie learning. We specifically study the process of learning to predict whether choices will lead to good or bad outcomes. We work closely with clinical collaborators, implementing tasks in animals that have shown differences between patients and controls, and taking findings from the animal work to help understand clinical populations. As we develop a better understanding of how these brain systems support learning, we can develop a better understanding of how pathology in these systems can underlie various psychiatric disorders including anxiety, depression and addiction. Our recent work has focused on broadening our understanding of the network of areas important for these learning processes. Current conceptions of the circuitry that underlies this learning focuses on dopamine and the ventral-striatum, whereas our recent work also points to an important role for the amygdala. Ongoing work examines whether different neural systems underlie learning from positive vs. negative outcomes (rewards vs. punishments), and whether overlapping or distinct neural systems underlie learning actions that are beneficial vs. learning to choose objects that are beneficial. We have also recently studied increasingly sophisticated learning mechanisms and found that prefrontal cortex represents learning processes that take advantage of contextual regularities in the environment. We developed computational models that predict how neural activity changes over time in prefrontal cortex and the striatum when we learn to associate actions with rewards. Finally, we have used computational modeling to dissect threat learning in patients with anxiety disorders into mechanisms related to the neural systems we study.