Reafferent or Redundant: Integration of Phonotaxis and Optomotor Behavior in Crickets and Robots

A general problem in understanding the mechanisms underlying animal behavior is the integration or interaction of different sensorimotor systems. Webb and Harrison (2000a, b) investigated the addition of an optomotor reflex to a sound-localizing robot modeled on cricket behavior. Böhm, Schildberger, and Huber (1991) proposed a simple additive mechanism to explain how the cricket combines the two behaviors. Problems implementing this on the robot led us to propose an alternative inhibition mechanism, which proved effective. Here we directly compare these two possibilities and several further alternatives. First, in a simulation of the open-loop paradigm used by Böhm et al. we demonstrate that there are at least five algorithms (including “efferent copy”) that may adequately account for the data they present. We then consider possible neural implementations of several of these schemes, and test them in robot experiments. The results suggest that inhibition is both neurally plausible and effective as a means of combining these behaviors in real sensorimotor situations.