First Advisor

Randy Zelick

Term of Graduation

Summer 1998

Date of Publication

9-9-1998

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Biology

Department

Biology

Language

English

Subjects

Electric fishes -- Sense organs, Electric organs in fishes

DOI

10.15760/etd.4151

Physical Description

1 online resource (iii, 62 pages)

Abstract

Weakly electric fish use a combination of active electrolocation and passive mechanosensory receptors for object detection and analysis. When tested with repeated presentations of the same moving object, Brachyhypopomus pinnacaudatus showed a gradual habituation of its electric organ pacemaker acceleration response (novelty response) that was unaltered by changes in the replacement electric organ discharge (S1 ). When tested with objects of differing velocities, the novelty response of the fish was proportional to the change in velocity of object. The responses of fish to objects that presented different mechanosensory profiles, but equal electrosensory profiles, suggest that the fish used the electrosensory system as its dominant sensory input. The fish exhibited no response to a change in the mechanosensory profile of the object (p=.240). When the electric organ discharge (EOD) was suppressed, the fish was able to distinguish between the two electrically similar but acoustically different objects (p=.036). Experiments with objects that differed in both electrosensory and mechanosensory properties yielded similar results, vvith the fish's ability to detect similar objects improved by the removal of the EOD (p=.005 vs. p=.001 ). This may be due to the lower novelty response shown by the terminus of the electrosensory afferents.

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Persistent Identifier

https://archives.pdx.edu/ds/psu/44697

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