Postoperative haptic training facilitates the retrieval of visual-based memories after visual cortex lesions in rats

Two experiments examined the effects of postoperative haptic discrimination training on the relearning of a maze visual discrimination in rats with visual cortex lesions. In the first experiment, rats learned a visual intensity discrimination prior to ablation of the lateral Oc2L cortex. Lesion rats were exposed to either a rough/smooth haptic discrimination training condition, a random training condition, or a no-training condition prior to relearning the visual task. Lesion rats relearned the visual task faster after haptic training than after other postoperative experiences. The second experiment replicated these procedures but with rats in which most of the visual cortex was removed. The lesion-induced relearning deficits in the second experiment were similar to the deficits seen for the smaller Oc2L lesions in the first experiment, supporting the hypothesis that the lateral visual cortex is critical for intensity discrimination. Haptic training also reduced these deficits, but the magnitude of this effect was related to the characteristics of the haptic cue. Postoperative training with haptic cues can produce specific and nonspecific information transfer from the intact somatosensory system to the damaged visual system that can facilitate the visual relearning. Possible implications for neuropsychological rehabilitation are also discussed.