Short-range navigation in the weakly electric fish Gnathonemus petersii L. (Mormyridae, Teleostei).
Item
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Title
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Short-range navigation in the weakly electric fish Gnathonemus petersii L. (Mormyridae, Teleostei).
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Identifier
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AAI9304643
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identifier
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9304643
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Creator
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Cain, Peter.
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Contributor
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Adviser: Peter Moller
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Date
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1992
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Psychobiology | Biology, Zoology
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Abstract
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This two-part investigation examined the role of electrolocation and vision in short-range navigation and orientation in Gnathonemus petersii, a weakly discharging electric fish. Each fish was placed in one compartment of an aquarium divided in half with a clear plastic wall. An aperture connecting the compartments appeared in one of three positions determined by randomized block design. The experimental chamber provided a novel environment the fish began exploring. The length of time (T) it took the fish to find an aperture in the wall, the height (H) they contacted the wall and the electric organ discharge (EOD) rate were recorded. In part I, 70 fish were divided into two groups: experiment 1, five groups of ten fish each; experiment 2, one group of 20 fish. The goal was to determine the effect of selective sensory deprivation on the fish's ability to locate the aperture. Fish with a functioning electric organ located the aperture faster, increased the height they contacted the wall, and changed their EOD rate.;In the second experiment, the aperture position remained fixed, and 20 fish learned to find and use the aperture. After four trials, the electric organ of ten fish was surgically rendered inoperative (silenced). The next day, all 20 fish were tested. There were no differences between intact and electrically-silent groups in time and height measures.;In Part 2, one hundred fish were divided into two groups of 50 fish each. The goal was to determine if fish with various degrees of sensory deprivation could learn the location of a fixed aperture. In experiment 1 the position of the aperture was raised by 10 cm after four trials. Over four trials, intact, blind, silent, and sham-operated fish learned the position of the aperture. When the aperture was raised immediately following trial 4, fish with a functioning electric organ decreased the time to find the aperture, and increased the height they touched the wall. In experiment 2, following four trials to familiarize the fish with the environment, the water level was raised by 10 cm (leaving the aperture in place). When the water level was raised, all fish increased the height they contacted the wall. This increase, in response to a rapid change in water depth, suggested that all fish used hydrostatic pressure cues to maintain depth orientation.;The data show that G. petersii develop a central expectation or internal representation of their environment involving electrosensory and hydrostatic cues. As the environment becomes more familiar, the fish cease to attend to electrosensory information, and navigate according to the central expectation.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
