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

Abstract

Blinded rats with either no preoperative training, preoperative training to criterion, or 100% overtraining were tested for the ability to make tactile discriminations after somatosensory cortical lesions or control operations. Postoperative deficits on the first tactile discrimination (retest) varied with the amount of preoperative training. Animals having no preoperative training showed the most severe deficits, and although trained and overtrained lesion groups did not differ from each other, only the overtrained rats with lesions did not differ from controls. All three lesion groups performed poorly in postoperative acquisition of a new and more difficult tactile discrimination. These data suggest that postoperative performance on a given task may vary as a function of the amount of preoperative training on that task, but that increased practice on one discrimination may not minimize lesion effects on a new, more difficult problem in the same modality.