Wind Spectra and the Response of the Cercal System in the Cockroach

Experiments on the cercal wind-detection system of American cockroach, Periplaneta americana, showed an unexpected relation between the bandwidth of a random noise series of wind stimuli and the firing rate of the interneurons coding wind information. The firing rate was shown to a) increase with decreases in the stimulus bandwidth and b) be independent of changes in the total power of the stimulus for the same spectral composition. A phenomenological model of these relationships and their relevance to wind-mediated cockroach behavior is proposed. A detailed analysis of ethologically relevant stimulus parameters and the experimental system used to generate and control them is presented.