Sensory systems detect features of the external world, which are represented in the activity of ensembles of neurons in the brain. My lab seeks to understand how sensory information is represented in the brain and how internal representations acquire meaning that can be used to inform behavior. Animals have evolved neural circuits that drive innate behavioral responses to environmental cues that have been essential to the survival of a species over long periods of evolutionary time. However, most stimuli do not have innate significance. Rather, meaning is acquired over the lifetime of an animal through learning. We exploit the sense of smell to investigate how sensory representations afford meaning for innate and experience-dependent behavior. We use endoscopic 2-photon calcium imaging to monitor neuronal activity, and molecular genetics, viral tracing and optogenetics to trace and manipulate the neural circuits of the mouse brain.