Temporal hyperacuity in the gymnotiform electric fish, Eigenmannia

Abstract

SYNOPSIS. The gymnotiform electric fish, Eigenmannia, exhibits extraordinary sensitivity to small timing differences between sensory signals. The jamming avoidance response, gradual frequency shifts of the electric organ discharges, requires the detection of temporal disparities between sensory signals impinging upon different electroreceptors. This behavior occurs reliably even with temporal disparities being smaller than one microsecond. Since individual sensory receptors are not capable of encoding such minute timing with certainty, the high behavioral sensitivity must, therefore, emerge from signal processing within the central nervous system. Individual neurons, at the top of a well defined neuronal hierarchy have been found to be sensitive to temporal disparities in the range of 1 microsecond. The response properties of these neurons as well as behavioral results suggest that spatial convergence of sensory information plays a major role in the emergence of this temporal hyperacuity. © 1993 by the American Society of Zoologists.