Adaptive Filtering in the Electrosensory System

Abstract

Certain marine and freshwater fishes have the ability to detect weak electric fields. One of the principal uses of this sense is to detect electric fields (or electric field perturbations) caused by nearby objects. Detection of these weak extrinsic signals is complicated by the fact that the signals of interest are often swamped by larger signals associated with the fish’s own motor activity. In several cases that have been studied, part of the solution to this problem seems to involve adaptive filtering at the first stage of electrosensory processing in the central nervous system. Although distantly related in evolutionary terms, the electrosensory systems of elasmobranch, mormyriform and gymnotiform fishes share important similarities in the structure and function of the primary electrosensory nucleus, suggesting that they may have converged on similar mechanisms for adaptive filtering.