Impairment and recovery of visual functions after bilateral lesions of superior colliculus

Adult, male hooded rats were tested on a six-choice jumping stand apparatus designed to study their ability to perform visually guided orientation movements with a brightness discrimination task. Upon reaching criterion, the rats suffered either one- or two-stage, bilateral electrolytic lesions of the superior colliculi and then, after a brief recovery period, were retested for their ability to retain the preoperatively learned task and, in addition, perform a more difficult task. Although both brain damaged groups evidenced an impairment in comparison to sham-operated controls, the rats with two-stage lesions were less disabled than their simultaneously operated counterparts.