PROJECT SUMMARY (See instructions): What operations are performed by the mammalian central nervous systems to coordinate and conduct voluntary movement? Motor systems neuroscience seeks to understand these neural mechanisms. The last two decades have witnessed a transformation in this field with the use of multielectrode recordings and statistical estimation and modeling techniques. These technological advances have yielded rich, low-dimensional neural dynamics that are suggestive of the mechanisms underlying behavior. To minimize confounds, the overwhelming majority of these studies utilize behavioral constraint to isolate just the behaviors of interest for study. While effective for generating many behaviorally similar trials, this may have the unintentional consequence of artificially constraining neural dynamics to a subset of its full range. This project seeks to better understand the full repertoire of behavior in a freely-moving setting and model this neural activity using novel computational tools. This project combines the expertise of two neuroscientists with complemenary skillsets spanning systems and computational neuroscience. This project will involve acquiring novel, freely-moving data using the recent advances in depth imaging cameras and modeling the dynamics of the labelled neural data with innovative switching dynamical models. TThis combined expertise will be applied to the investigation of the initiation vs sustaining of movement, the decomposition of walking periods into distinct dynamical regimes, and an analysis of foraging behavior. Taken together, these studies will further our understanding of how neural dynamics drive unconstrained motor behavior. This insight has implications for the development of ambulatory brain-machine interfaces and may inform the treatment of individuals with motor disorders such as stroke.