The role of superior colliculus in vision: visual form discrimination in cats with superior colliculus ablations.

The rate of acquisition of visual form discriminations in cats with superior colliculus damage was measured in a testing apparatus requiring a minimal amount of stimulus localization in space. In animals with bilateral superior colliculus ablations, acquisition was imparied relative to acquisition in normal animals. In these animals, the extent of the lesion was related to the severity of the deficit. In split-brain preparations with unilateral superior colliculus ablations, acquisition with the eye ipsilateral to the lesion was impaired relative to acquisition with eye contralateral to the lesion. The deficits observed did not depend upon damage to pretectum. The results support the conclusion that the superior colliculus participates in certain aspects of form vision.