| Abstract: | The effects of caudate-putamen lesions in the rat on conditioning were investigated in 3 experiments. In Exp I, rats with lesions were impaired on a spatial task that required learning to make the correct position response, but no deficit was obtained when the alternatives were differentiated by salient visual cues. Performance remained good even when the visual cues were removed. A classical conditioned suppression paradigm was used in Exp II, and caudate-putamen lesions were found not to impair acquisition of suppression or overshadowing. In Exp III poor instrumental learning in subjects with lesions as retarded acquisition of lever-press responding and depressed variable interval response rates were found. When a light stimulus was present together with reinforced responses, response rates were depressed in the control group (which suggested an overshadowing phenomenon) but were potentiated in the group with lesions. Results show that caudate-putamen lesions did not produce a general deficit in association formation. There was disruption of learning about responses but not stimuli and, moreover, it was found that redundant stimulus cues aided response learning. It appears that for normal subjects, the salience or associability of the response cues may largely-determine the influence of stimuli presented during instrumental conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
