Evidence of an extended representation of the visual field in the superior colliculus of the rabbit (Oryctolagus cuniculus).

Electrophysiological mapping using multiple-unit criteria was employed to study the representation of the visual field in the superior colliculus of the rabbit. It was found that the contralateral superior colliculus of the rabbit has an extended representation beyond the representation of the zero vertical meridian or the line of decussation in the geniculostriate system. The amount of extended representation in the contralateral superior colliculus is coextensive with the extent of visual field represented ipsilaterally in areas 17 and 18 of the visual cortex. In agreement with previous findings, the representation of the visual field on the superior colliculus is extremely distorted. Finally, no evidence of an ipsilateral input can be produced.