“We are what we repeatedly do”. Throughout life, individuals continuously decide which actions to take, when and how to execute them, and how to update future behavioral strategies based on action outcomes, in order to obtain reward, avoid harm, and adapt to changing environments. These processes require the brain to integrate sensory information, motivational states, temporal structure, action values, and behavioral consequences. The basal ganglia circuits play central roles in action selection, motor control, reinforcement learning, and adaptive decision-making. Dysfunction of these processes is implicated in many neurological and neuropsychiatric disorders, including Parkinson’s disease, Huntington’s disease, obsessive-compulsive disorder, depression, and addiction. Our lab aims to understand the neural circuit mechanisms and computational principles by which the brain selects, executes, and reinforces actions. We employ a synergistic combination of experiments and theory to address these three distinct but related questions.

(1) Action selection: How does the brain govern the selection of desired action and inhibition of competing actions? What are the neural bases underlying the action selection/decision making under motivational conflicting conditions (such as cost-benefit conflict and risky decision)?

(2) Action execution: How does the brain modulate the movement kinematics (such as vigor)? How does the brain control movement initiation and represent action sequences? What are the neural bases underlying the graded control and coordination of continuous movements?

(3) Action reinforcement: How does the basal ganglia-dopamine system reinforce the “good” actions and discourage the “bad” actions? How is the basal ganglia system modulated by the monoamines during the learning process? How do monoaminergic and cholinergic systems regulate learning, salience processing, and action-value updating?