Multielectrode registration of episodic discharges generated by weakly electric fishes

Abstract

Purpose of this study introduces a multielectrode array (MEA) registration system in order to generate electric field images of the episodic discharges generated by weakly electric fish. A multielectrode registration system has several important features: the design of the multielectrode lattice, the amplifier circuit, the choice of reference points for differential measurements, the recovery of the absolute values of the electric field potentials, and the application of principal components analysis. Methods. There are several advantages of our MEA registration as compared with the traditional twoelectrode registration: (a) the signal-to-noise ratio is significantly increased, (b) it is possible to construct the spatial distribution of the electric field for a single electric discharge, (c) the signals’ sources can be easily separated and identified, and (d) quantitative data on the electrical potential distribution can be obtained throughout the entire experimental tank. Results. The results illustrate an example of applied MEA registration. Electric discharges were recorded from a weakly electric catfish, Clarias gariepinus, using an array of 8 x 8 electrodes at a sampling rate of 20 kHz. Data show oscillograms and two-dimensional plots of the spatial distribution of the electrical field.