Abstract

The nictitating membrane responses of 6 rabbits were classically conditioned using electrical stimulation of the dorsal accessory olive(DAO) as an unconditioned stimulus and a tone as a conditioned stimulus. When compared to the conditioning d. control group using a standard unconditioned stimulus of periorbital electrical shock in the experiments of three stages, the conditioning produced by DAO stimulation is similar to the controls. In acquistion of conditioned nictitating membrane response, animals trained with DAO stimulation were slightly restarded than those with periorbital electrical shock but both groups eventually reached to a conditioning criterion of 80% CRs. After overtrained with DAO stimulation, conditioning of contralateral nictitating membrane responses with periorbital shock as unconditioned stimulus followed and the rate of conditioned response acquisition measured. It was observed that rapid acquisition occured during contralateral conditioning with periorbital shock. There was no significant differenc between DAO stimulation group and periorbital shock group in the rate of extinction. These results indicate that stimulation of the DAO can serve as an effective US to be identical to periorbital electrical shock. Therefore, the present, experiments, suggest that DAO forms a portion of the US pathway conveying information about the occurrence of an US to the cerebellum.