Exploring Cerebellar Contribution to Motor Optimization in Temporal Prediction Through Cerebellar–Brain Inhibition

The cerebellum integrates temporal information to optimize motor responses through prediction. Temporal prediction occurs through two mechanisms: rhythmic entrainment to recurring patterns or integration of single isolated intervals, guiding attention and enhancing perceptual and motor performance. However, the causal contribution of the cerebellum–M1 pathway to motor optimization across predictive contexts remains unexplored. This study aimed to assess whether functional cerebellum-M1connectivity is modulated during a temporal prediction task requiring motor response optimization via a predictive process. Thus, we investigated Cerebellar-Brain Inhibition (CBI), a transcranial magnetic stimulation (TMS) technique, during a temporal prediction (TP) task. Twenty participants received the CBI protocol at rest and during the TP-task. Response times (RTs) to the target were recorded in two predictive contexts: rhythmic (i.e., interstimulus intervals were constant, 900 ms) and single-interval condition (i.e., target’s timing estimation was based on the prior exposure to the train of stimuli). TMS was delivered at two time points of the task: at the warning signal, corresponding to the maintenance of timing information for motor preparation and at the target stimulus onset, indexing use of timing information for motor execution. We found a significant reduction of the CBI with respect to rest only when participants were engaged in the single-interval condition of the TP-task. Furthermore, this modulation was evident only when TMS was delivered at the warning stimulus appearance, and not at the target stimulus appearance. Our findings underscore the causal role of the cerebellum in motor optimization in a predictive context, critically in single-interval, memory-based timing.