Time-Delays during Processing of Sensory-Motor Events within the Cerebro-Cerebellar Network: An fMRI Study

Introduction: Experiments as well as theoretical models suggest a role of the cerebellum in the control of time-related processes. For the control of movements, models of cerebellar function focus on the prediction of movement sequences based on internal models allowing for faster reaction on new demands. On the other hand, the cerebellum controls ongoing movements online. The aim of this study was to analyze the chronological activation sequence of the cerebro-cerebellar network conducting temporally predictable and non-predictable sensory and motor events. Methods: The measurements were carried out at 1.5 T (Siemens Symphony). 9 probands were asked to execute a visual triggered finger-thumb opposing movement after a preparatory signal either exactly 1s or after a pseudorandomized time interval of 0.8–1.2s. A passively performed finger to thumb opposition movement served as complementary sensory stimulus. The execution of the finger-opposition was registered online. SPM2 was used to perform a random effect analysis. Conclusion: The sensory and motor cortico-cerebellar network showed a typical pattern (M1, S1, SMA, premotor-cortex, cerebellar network). After an analysis of the signal intensity time courses in the regions of interest a significant delay of activation (time to maximum) was found in the cerebellar regions with respect to the cerebral areas within the network (M1-lobVI and S1-lobVI) for sensory and motor stimulus, respectively. This favors the thesis of cerebellar online correction at least for the lobulus VI. The temporal resolution of the signal of an event-related task seems to be able to give an approximation of the chronological signal-sequence processing of central structures; in this case exemplified for the motorsensory cerebro-cerebellar network.