A motion tracking system for simultaneous recording of rapid locomotion and neural activity from an insect.

We have adapted techniques for studying the locomotion of tethered insects to analysis of rapid directional movements such as escape behavior. We describe here a computer-based motion tracking system that allows an animal to turn and run as rapidly as it does under free-ranging conditions, and that samples fast enough to accurately reconstruct the movements. Furthermore, we have designed chronic electrodes that allow for simultaneous extracellular recording of the activity of interneurons related to behavior. We used this system to record the escape response of tethered cockroaches, Periplaneta americana, and compared the data with those obtained from high-speed videographic analysis of the same animals under free-ranging conditions. In the motion tracking system, animals were normally responsive to sensory input, and expressed directional escape turning responses. This system allows details of an entire escape response (initial turn and subsequent running) to be quantified. These behavioral details can now be correlated with the discharge of key interneurons on a trial-by-trial basis.