The role of crossed and uncrossed optic pathways mediating black-white discrimination in rats with one eye enucleated at birth

Abstract It has been reported that rats with one eye enucleated at birth (OEB) are able to relearn a black-white discrimination task originally learned with both the visual cortices intact faster than rats monocularly enucleated at three months of age (OET) when relearning is made after the visual cortex contralateral to the remaining eye is destroyed. Two experiments examined the hypothesis that functional enhancement of uncrossed optic pathways produced by monocular enucleation at birth might be the sole factor to produce such a phenomenon. The results showed that faster relearning in OEBs could not be totally explained by the hypothesis, and suggest that only when (1) there is a learning effect in the visual cortex ipsilateral to the remaining eye produced by interaction of visual information through the callosal fibers with an increased amount of information through uncrossed optic pathways during original learning and (2) relearning is mediated by enhanced functioning of uncrossed optic pathways, would such phenomenon be produced.