Our laboratory investigates the neural mechanisms of motivated behavior in health and disease using several physiological and behavioral approaches. Using genetic tools and mouse models, we focus on the role of the neurotransmitter dopamine in modulating information processing and neural plasticity in the basal ganglia. We use a variety of behavioral paradigms to assess different aspects of behavior, but our core approach is the homecage operant paradigm. In these studies, mice live 24/7 in cages equipped with operant levers and cues and earn all of their food from interacting with the environmental conditions we establish. This provides a rich picture into how mice adapt to contingencies in their environment and generates rich, complex datasets, which we approach using computational models to fit and analyze these data. We complement behavioral studies with techniques that allow closer examination of underlying mechanisms, including electrophysiology, which allows us to investigate the synaptic plasticity that underlies learning, and cyclic voltammetry, a technique for directly measuring the release of dopamine. The goal is to use knowledge gained from these studies toward the development of new therapeutic approaches to neuropsychiatric disorders, with an emphasis on Parkinson’s disease, addiction and motivational aspects of obesity.