title: Role of the olivo-cerebellar system in timing.
abstract: Timing has been proposed as a basic function of the cerebellar cortex (particularly the climbing fiber afferents and their sole source, the inferior olive) that explains the contribution of the cerebellum to both motor control and nonmotor cognitive functions. However, whether the olivo-cerebellar system mediates time perception without motor behavior remains controversial. We used event-related functional magnetic resonance imaging to dissociate the neural correlates of the perceptual from the motor aspects of timing. The results show activation of multiple areas within the cerebellar cortex during both perception and motor performance of temporal sequences. The results further show that the inferior olive was activated only when subjects perceived the temporal sequences without motor activity. This finding is most consistent with electrophysiological studies showing decreased responsiveness of the inferior olivary neurons to sensory input during expected, self-produced movement. Our results suggest that the primary role of the inferior olive and the climbing fiber system in timing is the encoding of temporal information independent of motor behavior.
authors.affiliation: Neurology Service, Minneapolis Veterans Affairs Medical Center, Minneapolis, Minnesota 55417, USA.
authors.forename: Duo
authors.initials: D
authors.lastname: Xu
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: James
authors.initials: J
authors.lastname: Ashe
authors.forename: Khalafalla O
authors.initials: KO
authors.lastname: Bushara
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002525:Cerebellar Cortex / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity; D009847:Olivary Nucleus / Q000502:physiology*; D010775:Photic Stimulation; D011149:Pons / Q000502:physiology*; D013998:Time Perception