THE CONDITIONED EYEBLINK RESPONSE - A ROLE FOR THE GABA-B RECEPTOR

In well-trained animals, infusion of the GABA-B agonist baclofen into the cerebellar interpositus nucleus and overlying cortex abolished the conditioned response (CR) with no effect on the unconditioned respons e (UR) with doses at or above 5.0 mM. Infusion of the GABA-B antagonis t CGP 5584-5A alone had no effect on the CR or UR. However, administra tion of 5 mM baclofen soon after infusion of CGP 5584-5A (15 min) resu lted in no reduction of percent CR and only partial reduction of CR am plitude. Naive animals given interpositus infusions of baclofen during training showed no learning, yet learned normally in postinfusion tra ining. The distribution of (radiolabelled) baclofen was localized and remained within the cerebellum. The results presented here are consist ent with a growing body of literature supporting the hypothesis that t he memory trace for eyeblink conditioning is formed and stored in the cerebellum and may involve GABAergic mechanisms. (C) 1997 Elsevier Sci ence Inc.