The role of basal ganglia in reinforcement learning and imprinting in domestic chicks

Effects of bilateral kainate lesions of telencephalic basal ganglia (lobus parolfactorius, LPO) were examined in domestic chicks. In the imprinting pa radigm, where chicks learned to selectively approach a moving object withou t any explicitly associated reward, both the pre- and post-training lesions were without effects. On the other hand, in the water-reinforced pecking t ask, pre-training lesions of LPO severely impaired immediate reinforcement as well as formation of the association memory. However, post-training LPO lesions did not cause amnesia, and chicks selectively pecked at the reinfor ced color. The LPO could thus be involved specifically in the evaluation of present rewards and the instantaneous reinforcement of pecking, but not in the execution of selective behavior based on a memorized color cue. NeuroR eport 12:1743-1747 (C) 2001 Lippincott Williams & Wilkins.