Electrophysiological techniques are being used to investigate neuronal mechanisms controlling behavior using, as a model system, the escape response of the American cockroach, Periplaneta americana. Initially chronically implanted electrodes are being used to stimulate and record from nerve cells in intact, behaving animals; interactions between elements identified as being important for the response will be investigated later with microelectrode readings. Particular attention will be given to the function of the abdominal giant fibers in initiating the response, the role of reafference (input generated by the animal's own activities) in producing prolonged activity, the time course and site of habituation, and decision making by the nervous system, exemplified here by the switch between running and flying which depends on afferent information from leg receptors. Investigations will also continue on contraction kinetics and synaptic physiology in the sound producing muscles of the katydid, Neoconocephalus robustus, which are of interest because of their extraordinary contraction frequency, up to 200 per second.