Understanding how neural processes are translated into complex behaviors and mental states is one of the most challenging frontiers of neuroscience. Neuroscientists intrigued by this question study problems such as learning and memory, emotion and motivation, behavioral state regulation, complex information processing and cognition. Many of these investigators utilize tools and approaches that are multidisciplinary, incorporating methodologies and theoretical frameworks from physiology, psychology, molecular biology, and computational neuroscience. There are a number of strong and active research groups at the University of Wisconsin-Madison addressing these questions. One group uses state-of-the-art neuroimaging tools (functional MRI and PET) to examine the human brain during cognitive tasks or emotional states. Other faculty employ animal models to investigate brain substrates of motivated behavior, such as feeding, sexual behavior, aggression, stress responses, and drug-seeking behavior. There are a number of researchers focusing on organization of brain systems that control behavioral states, such as sleep and wakefulness. Other significant research areas include the study of neural pathways involved in language and sensory processing. Levels of investigation are often multifaceted; for example, researchers may be interested in correlating neurochemical, neurophysiological, endocrine, or molecular and genetic processes with behavioral states.