Overview

The lab is interested in determining the neural basis of normal motivated behaviors including feeding and drinking as well as maladaptive behaviors such as drug-taking and the over-consumption associated with obesity. The nucleus accumbens and the neurotransmitter dopamine are critical brain substrates involved in motivated behavior including feeding and drug-taking. Since the nucleus accumbens accesses motor-related structures, it is well suited to modulate behavior based on changes in motivational state and learned associations. Our research seeks to determine how signaling in the nucleus accumbens is altered in response to changes in motivated state and learned associations. To accomplish this, we employ two state-of-the-art recording techniques combined with detailed behavioral analyses. Electrophysiological recordings of many single neurons and electrochemical (fast-scan cyclic voltammetry) recordings of dopamine release in the nucleus accumbens are made in real-time during behavior. These two recording techniques are performed while rats taste rewarding and aversive stimuli or are working to obtain food or drug rewards. Learned associations are manipulated by pairing a rewarding taste with illness thereby rendering it aversive in the future. Motivational state is altered by food or water restriction or by the delivery of hormones or neuropeptides to mimic need-states or satiety. Finally, we are interested in whether the propensity to take drugs, such as cocaine, can be altered through the delivery of hormones or neuropeptides that affect food intake. This program of research will shed considerable light on human disorders of motivation such as obesity and drug-addiction.