The goal of our research is to understand how the central nervous system performs the complex functions underlying learning and memory by mapping metabolic and electrical activity within and between functional groups of cells. Is there one central learning circuit for sensory information or are there several circuits depending on the type of learning and/or the sensory modality? Our laboratory group is identifying the neural functional maps underlying various types of learning including delay nonmatching to sample (DNMS), classical and operant conditioning using auditory and visual stimuli. By using whole brain metabolic mapping techniques such as 2-deoxyglucose (2-DG) autoradiography and cytochrome oxidase (C.O.) histochemistry, the neural circuit differences between auditory versus visual stimuli, classical and operant conditioning, and acquisition vs. maintenance, of behavioral patterns using a variety of sensory cues are being delineated. The neural circuits that are identified with metabolic mapping techniques are then verified and refined in rodents and primates through permanent lesion and temporary inactivation studies as well as neuronal recording studies.