A positive role of noises in accurate detection of time difference by electrosensory system of weakly electric fish

Weakly electric fish Eigenmannia can discriminate with an accuracy of the o rder of 1 mu s whether the phase of its own EOD signal is advanced or delay ed compared with that of its neighbor's signal. To clarify the neural mecha nism accomplishing the hyperaccurate discrimination, we present a neural mo del of the torus. The time difference between afferent nerve spikes arising from different sites on the body surface is detected by the two-dimensiona l array of small cells in the torus. The phase advance and delay are detect ed by integrating the outputs of small cells. The hyperaccurate detection i s accomplished by the stochastic resonance induced by the spatio-temporal i ntegration of the outputs including noises. (C) 2000 Elsevier Science B.V. All rights reserved.