His laboratory is working to understand the cognitive basis of goal-directed behavior using behavioral, pharmacological and neurophysiological techniques in rats. Efforts include defining the specific roles of orbitofrontal cortex, basolateral amygdala, and the accumbens in associative learning and decision making in normal intact rats, characterizing the effects of normal (non-pathological) aging on function in the orbitofrontal system, and understanding the effects of chronic drug use on normal function in the orbitofrontal system.