Reinstatement of orienting behavior by d-amphetamine in rats with superior colliculus lesions

The involvement of the nigrotectal pathway in the expression of visual orienting behavior was assessed by a combination of superior colliculus (SC) lesions and increased dopamine transmission produced by administration of d-amphetamine. Orienting behavior elicited by apparently moving or stationary light displays, its habituation, and recovery were observed. In intact animals, amphetamine injections had a small but reliable effect on the habituation of orienting behaviors. Rats with SC lesions did not orient to the lights. Amphetamine-injected rats with SC lesions did orient, and the topography of their orienting behavior, rate of habituation, and recovery of orienting with changes in the light display were comparable to those of the intact animal. These results suggest a view of SC-lesion-impaired orienting behavior as a disturbance of sensory attention and emphasize the interaction of the SC and other neural systems in processes mediating the direction of attention.