The predictability of target occurrence has influence upon the latency of motor initiation. Higher frequencies (>0.5 Hz) of periodically paced target presentation lead to decreased latencies of movement initiation. In this study we investigated the initiation of head movements and saccades during predictable and random target presentation in cerebellar patients. During the predictive condition, in particular during higher temporal frequencies and greater amplitudes, patients showed increased latencies compared to healthy subjects. The latencies between the onset of the agonistic and antagonistic muscle pulses were correlated with the severity of cerebellar impairment. We conclude that the cerebellum is involved in predictive response initiation of eye and head movements which is emphasized at higher temporal frequencies.
The predictability of target occurrence has influence upon the latency of motor initiation. Higher frequencies (>0.5 Hz) of periodically paced target presentation lead to decreased latencies of movement initiation. In this study we investigated the initiation of head movements and saccades during predictable and random target presentation in cerebellar patients. During the predictive condition, in particular during higher temporal frequencies and greater amplitudes, patients showed increased latencies compared to healthy subjects. The latencies between the onset of the agonistic and antagonistic muscle pulses were correlated with the severity of cerebellar impairment. We conclude that the cerebellum is involved in predictive response initiation of eye and head movements which is emphasized at higher temporal frequencies.