Task-specific deficits in reversal performance following superior colliculus lesions in rats

Rats with lesions of the superior colliculus or control operations were tested in acquisition, extinction and reversal performance of operant visual tasks in four experiments. The tasks used in the experiments were: a simultaneous choice task (Experiment 1), a successive choice task (Experiment 2), a simultaneous go/no-go task (Experiment 3) and a successive go/no-go task (Experiment 4). Acquisition discrimination performance was affected by lesions only in Experiment 3, where in contrast with previous reports animals with lesions performed better than controls. Reversal performance of animals with lesions was impaired in Experiments 1 through 3, but not in Experiment 4. Effects on extinction performance were minimal in all experiments. The data are interpreted to indicate a role o the superior colliculus in the processing of spatial information.