Abstract
The research reported here was concerned with the role of learning in recovery of function after brain damage. Three experiments were carried out. All of the experiments involved hooded rats trained in a two-choice brightness discrimination when treated with the RNA antimetabolite 8-azaguanine. In normal rats, this drug severely interferes with the acquisition of learned behaviors but not the performance of previously learned behaviors. The first experiment of the present series tested whether this finding was also true for rats required to learn a brightness discrimination without their visual neocortices. The results replicated what was found with normal rats—acquisition was impaired but performance was not. The second experiment investigated the effects of 8-azaguanine on the recovery of a preoperatively acquired brightness discrimination following posterior decortication. The prediction was that if learning was involved in the recovery process, then recovery under the influence of 8-azaguanine should be impaired. However, contrary to this prediction, the recovery process was actually facilitated when the animals were treated with 8-azaguanine. The third experiment tested whether the facilitation found in Experiment 2 was some general facilitation of recovery of function or specifically related to the disruption of learning by 8-azaguanine. The procedure involved testing for recovery of a preopoperative brightness discrimination under conditions where it was reasonable to conclude that the recovery process was a relearning process. In this situation, the drug 8-azaguanine impaired recovery of function. On the basis of these data, we suggest that postoperative learning can interfere retroactively with the reinstatement of spared neural mechanisms when these neural mechanisms are effective in the recovery process.
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LeVere, T. E., Gonder, L., & Davis, N. Recovery of function after brain damage: An evaluation of whether the destruction of motivational systems may be responsible for the visual deficits following striate lesions. Manuscript submitted for publication, 1978.
Davis, N., & LeVere, T. E. Recovery offunction after brain damage: An explanation of the nature of the behavioral deficit following neocortical injury. Manuscript submitted for publication, 1978.
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This research was supported by Research Grant NS-12459 from the National Institute of Neurological and Communicative Disorders and Stroke, U.S. Department of Health, Education and Welfare, to T. E. LeVere. The authors wish to thank P. Knowles for her assistance in the preparation of this report.
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Davis, N., LeVere, T.E. Recovery of function after brain damage: Different processes and the facilitation of one. Psychobiology 7, 233–240 (1979). https://doi.org/10.3758/BF03326631
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DOI: https://doi.org/10.3758/BF03326631