Recovery of pattern discrimination ability in rats receiving serial or one-stage visual cortex lesions.

Two groups of 10 hooded rats were trained on a pattern discrimination between horizontal and vertical striped stimuli which were equated for contour-length and total luminous flux, and in which consistent local luminous flux cues were eliminated. In one group of rats, visual cortex removals were performed in two stages with training between the operations. Nine out of the 10 rats were able to relearn the pattern discrimination (median of 344 trials) after the completed bilateral visual cortex lesions in one stage. In agreement with previous studies, none of these animals were able to relearn the discrimination after more than 10 times (550 trial limit) the trials required for original learning. However, several rats with total one-stage lesions could relearn the pattern discrimination if very extended periods of training were given.