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International Journal of Zoology
Volume 2010, Article ID 762621, 14 pages
http://dx.doi.org/10.1155/2010/762621
Research Article

Responses of Medullary Lateral Line Units of the Goldfish, Carassius auratus, to Amplitude-Modulated Sinusoidal Wave Stimuli

Institute of Zoology, University of Bonn, Poppelsdorfer Schloss, 53115 Bonn, Germany

Received 13 November 2009; Revised 11 March 2010; Accepted 8 April 2010

Academic Editor: Randy J. Nelson

Copyright © 2010 Ramadan Ali et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper describes the responses of brainstem lateral line units in goldfish, Carassius auratus, to constant-amplitude and to amplitude-modulated sinusoidal water motions. If stimulated with constant-amplitude sinusoidal water motions, units responded with phasic (50%) or with sustained (50%) increases in dicharge rate. Based on isodisplacement curves, units preferred low (33 Hz, 12.5%), mid (50 Hz, 10% and 100 Hz, 30%) or high (200 Hz, 47.5%) frequencies. In most units, responses were weakly phase locked to the carrier frequency. However, at a carrier frequency of 50 Hz or 100 Hz, a substantial proportion of the units exhibited strong phase locking. If stimulated with amplitude-modulated water motions, units responded with a burst of discharge to each modulation cycle, that is, units phase locked to the amplitude modulation frequency. Response properties of brainstem units were in many respects comparable to those of midbrain units, suggesting that they emerge first in the lateral line brainstem.