LIGHT DARK DISCRIMINATION AFTER SCIATIC-NERVE TRANSPLANTATION TO THE SECTIONED OPTIC-NERVE IN ADULT HAMSTERS

In adult golden hamsters (Mesocricetus auratus), the optic nerve was bilaterally sectioned with one side grafted with the sciatic nerve to make a bridge to the ipsilateral superior colliculus. Shuttle-box avoidance was tested using light as the conditioned stimulus. Three of the five transplanted animals revealed statistically significant increase in percentages of avoidance. A significant increase in the avoidance scores was also observed in 15 normal hamsters, but none of 13 blind hamsters showed such an increase. Intertrial responses, which represent spontaneous responses, did not show significant changes. We conclude that some of the transplanted animals can discriminate between light and dark, probably through their restored visual pathway.