We are applying biophysical and quantitative methods to the analysis of locomotion and sensory behavior in simple organisms (E. coli, C. elegans). Our approach is to develop new instrumentation and techniques that allow us to measure and analyze behavioral responses at the motor output level. This systems-level approach will help us detail the molecular, cellular, and neuronal components involved in these pathways, and allows us to ask questions that span a number of traditional scientific boundaries such as sensory biology, systems neuroscience, theoretical neuroscience, and sensory ecology.