Electric Discharge

Electric Discharge - Background Electric marine animals...

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Background Electric marine animals such as the black ghost knife fish, Apteronotus albifrons, generate electric fields and sense their distortion to navigate since vision is usually poor in their um welt. These signals are generated by their electric organs located in the rhombencephalon, and perceived by tuberous electroreceptors which receive signals that are directed azimuthally to the skin ( source ). This behavior provides a good example for efference copy as well. Each time a fish sends out a “click”, or electric organ discharge (EOD), it anticipates to “hear” it. If it does not hear the click, the animal knows that something in its environment is distorting its signal. Command signals going out (efferent) are send to the central nervous system to make computation and provide a template of expectation to minimize sensory input from its own actions. Said another way, efference copy enhances the salience of sensations that have an external cause. Introduction Having two or more waves interfering with each other will produce constructive or destructive interference, regardless if they are in-phase or out of phase. Either way, the distortion of signal is detrimental to the navigation and communication among electric marine animals. When another electric fish is in the area at a similar frequency (how “similar” will be examined in this lab), the fish will both change their electric organ discharge frequency. The fish at a higher frequency will increase its frequency, and the fish at the lower frequency will decrease its discharge to increase the separation in frequency. This jamming avoidance response (JAR) allows for a more accurate representation of the animals own signal to be perceived and transmitted for communication and navigation. The question we are examining is how similar the EOD frequencies need to be in order to induce an
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This note was uploaded on 04/07/2008 for the course BIO 3411 taught by Professor Waters during the Spring '08 term at Minnesota.

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Electric Discharge - Background Electric marine animals...

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