Cortical lesions and somesthesis in rats: Effects of training and overtraining prior to surgery

Weese, G. Daniel; Neimand, Douglas; Finger, Stanley

doi:10.1007/bf00234480

Cited by 31 publications

(11 citation statements)

References 15 publications

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“…These results, of course, are reminiscent of Gazzaniga's (1974) suggestion that certain memories may have more than one route of access and that those that do are more resistant to the effects of brain damage. We also believe that our results support Gazzaniga's conclusion that multiple routes may also underwrite the reported resilience of overtrained behaviors following brain damage (Chow & Survis, 1958;Lukaszewska & Thompson, 1967;Orbach & Fantz, 1958;Thatcher & Kimble, 1966;Weese, Neimand, & Finger, 1973).…”

Section: Behaviorsupporting

confidence: 86%

Recovery of function after brain damage: On deposits to the memory bank

1984

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The availability of spared memories following neocortical injury has been shown to be related to the similarity of preoperative learning and postoperative recovery situations. In the present research we questioned whether the nature of the memory itself might also be an important determinant of the availability of spared memories following neocortical brain injury. It was found that the changes that interfere with the postoperative retrieval of memories of behaviors learned for a single motivational state do not interfere with the postoperative retrieval of memories of behaviors learned to satisfy two concurrent motivational states. Apparently, the nature of the memory is an important determinant of its availability following neocortical injury. Lashley's (1935) demonstration that posterior visual decortication will completely disrupt a preoperatively learned visual behavior has been replicated many times (see D. R. Meyer & P. M. Meyer, 1977). Lashley's interpretation of this result as a lesion-induced memory loss has not, however, enjoyed the same degree of agreement. For example, experiments with amphetamine (Braun, P. M. Meyer, & D. R. Meyer, 1966) have shown that this drug will facilitate the postoperative recovery, but not the original acquisition, of a brightness discrimination. Moreover, striate lesioned rats require a significantly greater number of trials to reestablish the reversal of a brightness discrimination that was learned preoperatively than they do when the reward contingencies are identical to the preoperatively learned behavior (LeVere & Morlock, 1973, 1974. These results, and others summarized by LeVere (1975), could occur only if the memories of the preoperatively learned behavior were spared even though the neocortically injured rat was initially unable to perform the behavior.These data have two important ramifications concerning recovery of function. First, as suggested over a decade ago by D. R. Meyer (1972), the recovery oflearned behaviors may be not so much a process of relearning what was lost but rather of remembering what was spared. Second, and because of this, the progress of the recovery process should be directly dependent upon the availability of spared memories.Unfortunately, we know very little about the parameters that determine the postoperative availability of spared memories except that a high degree of parity between the pre-and postoperative training situations is apparently required. For example, if either the extrinsic stimulus con- ditions (LeVere, Davis, & Fontaine, 1977) or the animal's intrinsic motivational state are changed between preoperative learning and postoperative recovery, then the reversal impairment noted by and Morlock (1973, 1974) does not occur. This lack of interference during postoperative reversal training clearly indicates that the spared memory was unavailable to the lesioned animal when the conditions of postoperative recovery were not the same as the conditions of preoperative learning. The present research used this finding to further...

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Section: Behaviorsupporting

confidence: 86%

Recovery of function after brain damage: On deposits to the memory bank

1984

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“…The hypothesis that overtraining can lessen the deficits displayed by animals with cortical ablations was not supported by the findings obtained in the current investigation. This is interesting because overtraining has been found to attenuate tactile performance deficits after somatosensory cortical lesions on tasks not involving reversal learning (Weese et al, 1973). In addition, overtraining may also lessen the deficits that follow other cortical (Chow & Survis, 1958;Orbach & Fantz, 1958) and subcortical (Lukaszewska & Thompson, 1967) lesions when retention is assessed.…”

Section: Discussionmentioning

confidence: 99%

Brain damage and the overlearning reversal effect

1979

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Rats were either trained to criterion or given 100% overtraining on a tactile discrimination before receiving sham operations or frontal. somatic, or occipital cortex lesions. With preoperative training to criterion, the rats with frontal and somatic cortex lesions showed marked postoperative impairments when tested for reversal learning with the same tactile stimuli previously encountered, whereas animals with occipital cortex ablations did not differ significantly from sham-operated subjects. Preoperat.ive overtraining failed to improve postoperative reversal learning among the sham-operated animals , and it. did not attenuate the ablation effects displayed by rats with frontal or somatic cortex lesions. These data show that the overlearning reversal effect (ORE), which has ,been reported with visual and spatial stimuli, may be more difficult to demonstrate with tactile discriminanda. The findings further suggest that early reports of preoperative overtraining lessening postoperative lesion effects may have less generality than previously recognized. ZUBEK, J. P. Recent electrophysiological studie s of the cerebral cortex: Impl ications for localizat ion of sensory functions .

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“…The extent to which the effects of somatosensory cortical lesions can be circumvented or minimized has been the subject of a number of recent experiments with rats. In some of these investigations, spacing the cortical lesions over time ("serial lesions") resulted in performance like that of sham-operated animals (Finger et al, 197 1 ;Finger & Simons, 1976), and in other investigations excellent performance scores were noted after preoperative overtraining (Finger & Simons, 1976;Weese, Neimand, & Finger, 1973). In contrast, varying the postoperative recovery period from 2 weeks to 2 years did not enhance restitution in one experiment (Finger & Reyes, 1975), and this study now shows that increased tactile stimulation experienced prior to surgery and maintained throughout testing does not minimize the deficits associated with these lesions.…”

Section: Discussionmentioning

confidence: 99%

Postweaning environmental stimulation and somesthetic performance in rats sustaining cortical lesions at maturity

Finger

1978

Developmental Psychobiology

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Rats were enucleated at 28 days of age and were assigned to complex or relatively barren tactile environments for the duration of the experiment. Approximately half of the animals in each group received large, bilateral lesions of the somatosensory cortex when they were 60 days of age, and the remainder underwent sham operations. Twenty days later all groups were tested for the ability to master a series of tactile discriminations. Statistical tests revealed a highly significant lesion effect, but no environment or lesion x environment interaction effects. These sensory discriminative findings stand in contrast to some earlier reports which have shown that environmental complexity provided prior to or following other forebrain lesions can minimize error scores on simple learning tasks.

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Cortical lesions and somesthesis in rats: Effects of training and overtraining prior to surgery

Cited by 31 publications

References 15 publications

Recovery of function after brain damage: On deposits to the memory bank

Recovery of function after brain damage: On deposits to the memory bank

Brain damage and the overlearning reversal effect

Postweaning environmental stimulation and somesthetic performance in rats sustaining cortical lesions at maturity

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