INFLUENCE OF DORSAL RHIZOTOMY ON ACQUISITION OF A SUSTAINED AVOIDANCE RESPONSE IN RATS.
Item
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Title
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INFLUENCE OF DORSAL RHIZOTOMY ON ACQUISITION OF A SUSTAINED AVOIDANCE RESPONSE IN RATS.
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Identifier
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AAI8023730
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identifier
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8023730
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Creator
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RODIN, BARBARA ELLEN.
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Contributor
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Doreen Berman
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Date
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1980
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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, Physiological
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Abstract
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Although it has been reported that animals can acquire discrete responses, involving phasic contraction of dorsal rhizotomized musculature, it has not yet been demonstrated unequivocally that sustained responses, involving tonic contraction, can be acquired after dorsal rhizotomy. This question was investigated in rats after unilateral dorsal rhizotomy of a hind limb (T13-L6, left).;The experimental paradigm was a modification of one used by Horridge (1962) to study conditioned alterations in leg position in headless insects. Animals were suspended over an electrolyte solution (without vision of the hind limbs) with a monitoring electrode attached to one hind paw. The contingencies of the training situation were such that, whenever the monitoring electrode was in solution, shock was delivered to a sensate area of the trunk. Avoidance could be achieved if the monitoring electrode was removed from the fluid and maintained at a level above the fluid surface. Training was terminated when animals either achieved a predetermined criterion or received 15 sessions of training. Two dichotomous training variables were manipulated; the presence or absence of preoperative training and the order of training of the two hind limbs.;With sensate limbs, the sustained response was acquired rapidly both before and after surgery. With DR limbs, however, acquisition failed to occur under all conditions but one. The appropriate response was achieved with DR limbs only when the order of postoperative training was sensate limb: DR limb. In this case, acquisition was more rapid when there had been preoperative experience in addition to contralateral limb training. However, comparing the performance of DR limbs with that of sensate limbs, many more sessions were required for acquisition and a different response topography was found.;Failure to acquire the response with DR limbs could not be attributed to insufficient training since, when the maximum training allowed was extended from 15 to 45 sessions, acquisition did not ensue unless the contralateral sensate limb had been trained first. It was also found that acquisition with DR limbs, when it occurred, was not mediated by response-related changes in contiguous sensate body parts. When dorsal rhizotomy included these body parts (T11-S4, left), animals still acquired the response with DR limbs.;It was concluded that a sustained response cannot be acquired after dorsal rhizotomy unless animals are first informed of the response requirement by previous training with a sensate limb. This finding is the first to indicate a specific limitation of central feedback and/or residual peripheral feedback (such as that provided by ventral root afferents) in response acquisition after dorsal rhizotomy.
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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.
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Program
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Psychology
