QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Aguilera, P. A. Articles by Caputi, A. A. Search for Related Content PubMed PubMed Citation Articles by Aguilera, P. A. Articles by Caputi, A. A.

The Journal of Experimental Biology 206, 989-998 (2003)
doi: 10.1242/jeb.00198

Electroreception in G. carapo: detection of changes in waveform of the electrosensory signals

Pedro A. Aguilera and Angel A. Caputi^*

Departamento de Neurofisiología Comparada, Instituto de Investigaciones Biológicas Clemente Estable, Unidad Asociada a Facultad de Ciencias, Universidad de la República, Av. Italia 3318, Montevideo, Uruguay

^* Author for correspondence (e-mail: angel{at}iibce.edu.uy)

Accepted 10 December 2002

Electric fish evaluate the near environment by detecting changes in their self-generated electric organ discharge. To investigate impedance modulation of the self-generated electric field, this field was measured at the electrosensory fovea of Gymnotus carapo in the presence and absence of objects. Changes in local fields provoked by resistive objects were predicted by the change in total energy. Objects with capacitive impedance generated large variations in the relative importance of the different waveform components of the electric organ discharge. We tested the hypothesis that fish discriminate changes in waveform as well as increases in total energy using the novelty response, which is a behavioural response consisting of a transient acceleration of EOD frequency that can follow a change in object impedance. For resistive loads, the amplitude of novelty responses was well predicted by the increase in total energy. For complex loads, the amplitude of novelty responses was correlated not only with increases in total energy but also with waveform changes, consisting of reductions in the early slow negative wave and increases in the late sharp negative wave. The total energy and waveform effects appeared to be additive. These results indicate that G. carapo discriminates complex impedance based on an evaluation of different waveform parameters.

Key words: electric image, electrosensory, electric fish, Gymnotus carapo, feature discrimination

This article has been cited by other articles:

				S. R. Pluta and M. Kawasaki Multisensory enhancement of electromotor responses to a single moving object J. Exp. Biol., September 15, 2008; 211(18): 2919 - 2930. [Abstract] [Full Text] [PDF]

				R. Pusch, G. von der Emde, M. Hollmann, J. Bacelo, S. Nobel, K. Grant, and J. Engelmann Active sensing in a mormyrid fish: electric images and peripheral modifications of the signal carrier give evidence of dual foveation J. Exp. Biol., March 15, 2008; 211(6): 921 - 934. [Abstract] [Full Text] [PDF]

				A. C. Pereira, V. Centurion, and A. A. Caputi Contextual effects of small environments on the electric images of objects and their brain evoked responses in weakly electric fish J. Exp. Biol., March 1, 2005; 208(5): 961 - 972. [Abstract] [Full Text] [PDF]

				A. A. Caputi, P. A. Aguilera, and M. E. Castello Probability and amplitude of novelty responses as a function of the change in contrast of the reafferent image in G. carapo J. Exp. Biol., March 15, 2003; 206(6): 999 - 1010. [Abstract] [Full Text] [PDF]