Functional interactions between the cerebellum and the premotor cortex for error correction during the slow rate...

Although neuroimaging studies indicate that functional magnetic resonance imaging (fMRI) signal changes in the cerebellum (CB) during the performance of a target movement reflect functions of error detection and correction, it is not well known how the CB intervenes in task-demanded movement attributes during automated on-line movement, i.e., how the CB simultaneously coordinates movement rate and error correction. The present study was undertaken to address this issue by recording fMRI signals during the performance of a task at two different movement rates (0.4 and 0.8 Hz). The results showed that movement errors increased with increasing movement rates. We also demonstrated that activation of the left CB increased with decreasing movement rates, whereas activation of the ipsilateral (right) premotor cortex (PMC) increased with increasing movement rates. Furthermore, there were significant relationships between individual movement errors and left CB activation at both movement rates, but these relationships were not observed in the ipsilateral PMC. Taken together, it is suggested that during the performance of automated and well-controlled slow force production tasks, the interactions between cortical (right PMC) and subcortical (left CB) motor circuits, i.e., a functional dissociation between PMC and CB, is exclusively dedicated to controlling movement rate and error correction. In particular, the present results showing significant relationships between individual force-control errors and CB activation might reflect functional differences of an individual's internal model.