ISSN:
1432-1351
Keywords:
Electric fish
;
Electrosensory
;
Mauthner cell
;
Escape
;
Sensorimotor integration
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Once initiated, rapid escape responses of teleost fishes are thought to be completed without additional sensory modification. This suggests that the motor program for a particular response is selected for by the constellation of sensory cues existing at the time of the releasing stimulus. This paper presents initial evidence that a highly specialized, phylogenetically recent electrosensory system is integrated with a primitive motor system and allows an animal to continuously monitor its environment for producing accurate escape behaviors. Behavioral testing for directed startle responses in a “Y-maze” demonstrates that when presented immediately before an acoustic startle stimulus, electric fish (Eigenmannia virescens), direct their response away from the cue (a transient shorting of their electric field). Thus, electrosensory cues as brief as 100 ms provide directional information to the escape motor network. In electric fish that are curarized to facilitate intracellular recording, the normal electric organ discharge is attenuated. When an electronically generated replacement field of the same frequency and amplitude as the fish's normal signal is shorted, a fast-rising, 7 ms latency post-synaptic potential is evoked from the Mauthner cell. Similar PSPs are generated by turning the replacement stimulus on and off. In some recordings, removing the S1 replacement field elicits a rebound of other afferent activity to the Mauthner cell; replacing the field suppresses this activity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00193519
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