Cerebellar representation of the eyeblink response as revealed by PET.

Blink reflex-related areas in the human cerebellum were studied using [15O]H2O PET in eight healthy subjects. Eyeblinks were evoked by airpuff stimulation and recorded via surface electrodes. PET analysis revealed a cerebellar increase of regional cerebral blood flow in vermal lobule VI and a small ipsilateral paravermal extension in the eyeblink condition compared to rest.

Limb flexion reflex-related areas in human cerebellum.

Numerous studies have shown that the cerebellum is involved in classical conditioning of specific aversive reactions. Only few studies, however, have examined the exact localization of cerebellar areas involved in the control of unconditioned reflex responses. The present study investigated cerebellar areas, which are activated during eliciting of the limb flexion reflex in healthy controls using [15O]H2O PET.

Involvement of the human cerebellum in fear-conditioned potentiation of the acoustic startle response: a PET study.

Fear-conditioned potentiation of the startle response was used to study the role of the cerebellum in associative learning of non-specific aversive reactions in healthy human subjects using PET. Prior PET scanning initially neutral light stimuli were paired with painful electric shocks (fear-conditioning phase). Four PET-scans each were performed with presentation of acoustic startle stimuli (T), fear-conditioned light stimuli (L) or acoustic stimuli paired with light (LT, potentation phase).