Research overview:
Yes, I'll have another piece of cake: Electrophysiological and computational investigation of the neural mechanisms that influence motivation and choice.
Our brains are endowed with a powerful motivational system that guides our thoughts and actions. Whether eating that extra piece of cake, gambling, or having a cocktail or cigarette, this hedonic system can dominate other neural processes to influence our behavior (and ruin diets). Adaptive behavior, by which an animal chooses its actions based on previous experience with obtaining rewards and avoiding hardships in its environment, is critical for survival. However, this same system may produce maladaptive behaviors such as overeating and addiction in our modern environment in which high-calorie food and drugs that target the motivational system are readily available. In addition, it seems that malfunctions of the same neural circuitry may also be involved in the compulsive thoughts and actions in schizophrenia, obsessive compulsive disorder, and Tourette Syndrome. My goal is to understand how these neural systems are involved in relatively simple tasks, such as guiding behavior in a cued 2-choice task, so as to begin to understand how the brain gives rise to these more sophisticated behaviors.
I use computational and experimental approaches to explore how the brain encodes sensory information associated with or without reward, and how this impacts simple behaviors. I focus on how information is processed in circuits linking prefrontal cortex and ventral striatum, with a particular focus on the role of dopamine for regulating the integration of excitatory and inhibitory inputs in the striatum. Both dopamine and hippocampal inputs have been suggested to play key roles for regulating, or gating, what information passes through the striatum. My recent experimental work reveals that a mechanism of inhibition also plays an important role for shaping the response of striatal neurons to cortical inputs.
Dopamine has been shown to mediate both short-term modulatory effects on neural activity (modulation) and also long-term effects on synaptic efficacy (learning). I believe that both of these functions are important for controlling interactions of cortex and basal ganglia, and that an integrative approach is pivotal for teasing apart the role of dopamine mediated modulation and learning in the network. This belief drives my multifaceted approach to the problem. The following sections outline my ongoing research:
