Project Summary Chemosensation is an evolutionarily conserved sensory modality throughout the living organisms. Olfaction, one mode of chemosensation, has been shown to guide navigation and decision-making in animals of different phyla within the kingdom. However, using olfaction as a sensory cue to guide navigation is a complex problem. This is because the spread of odor molecules over large distances is governed by the chaotic and turbulent flow of fluids from the source to the searcher. Hence, the olfactory information that an animal receives dynamically varies along the different spatial scales. In spite of this complex sensory signal, rodents are remarkable at locating sources of airborne odors from large distances. The stochastic olfactory information during the naturalistic behavior of plume tracking then promotes adaptive motor behaviors to actively sense odor information, and implementation of efficient behavioral strategies to locate odor sources. The rodent olfactory system then serves as an excellent model to study how sensation guides motion and vice-versa in the mammalian brain. Current technologies available for chemical quantification are not feasible to correlate real-time odor inputs with behavior in freely moving animals. Hence, we first developed a method to record real-time olfactory information using low-cost sensors that can be mounted on a mouse’s head. This method then allows unprecedented level of analysis in studying how odor contacts guide behavior in plume-tracking mice. Here I propose experiments to combine this method with behavioral tracking to understand active sensing of odor information, and behavioral strategies employed during plume-tracking in mice engaged in odor-source localization task. These behavioral studies will lay the foundation for the study of the neural bases of sensorimotor integration during the naturalistic behavior of plume-tracking. Defining the neurophysiological bases of odor-guided navigation will be instrumental for understanding how human brains integrate sensation and motion, and treatment of disorders that alter this integration in disorders, such as schizophrenia and post- traumatic stress disorder.