Frequency-Dependent Effects of Cerebellar Repetitive Transcranial Magnetic Stimulation on Visuomotor Accuracy

Abstract

The cerebellum plays a critical role in acquiring visuomotor skills. Visuomotor task mastery requires improving both visuomotor accuracy and stability; however, the cerebellum’s contribution to these processes remains unclear. We hypothesized that repetitive transcranial magnetic stimulation (rTMS) of the cerebellum exerts frequency-dependent modulatory effects on both accuracy and stability in subjects performing a visuomotor coordination task (i.e., pursuit rotor task). We recruited 43 healthy volunteers and randomly assigned them to the high-frequency (HF), low-frequency (LF), and sham rTMS groups. We calculated changes in performance of the pursuit rotor task at the highest rotation speed and the minimum distance from target as indices of accuracy. We also calculated the intertrial variability (standard deviations) of time on target and distance from target as indices of stability. Visuomotor accuracy was significantly enhanced in the HF group and disrupted in the LF group compared to the sham group, indicating frequency-dependent effects of rTMS. In contrast, both HF and LF rTMS demonstrated no significant change in visuomotor stability. Surprisingly, our findings demonstrated that the accuracy and stability of visuomotor performance may be differentially influenced by cerebellar rTMS. This suggests that visuomotor accuracy and stability have different underlying neural mechanisms and revealed the possibility of training strategies based on cerebellar neuromodulation.

Cerebellar Non-Invasive Brain Stimulation: A Frontier in Chronic Pain Therapy

“…The protocols most commonly used are divided between high-frequency (>5 Hz) and low-frequency rTMS (≤1 Hz), which lead to increased and decreased neuronal excitability, respectively, mediated by long-term potentiation (LTP)and long-term depression (LTD)-like mechanisms. These effects have been tested widely on the cerebellum, where rTMS has been applied to increase or decrease cerebellar output to M1 or to study the effects of cerebellar stimulation on motor learning, coordination, and cognitive functions [74][75][76]. For instance, 1 Hz cerebellar rTMS results in increased MEP amplitude and decreased intracortical facilitation (ICF), which reflect a reduction in the cerebellar inhibitory control over M1 [77][78][79].…”

Baseline Cerebro-Cerebellar Functional Connectivity in Afferent and Efferent Pathways Reveal Dissociable Improvements in Visuomotor Learning

“…To examine visuomotor learning abilities before and after the cerebellar rTMS intervention, participants performed the pursuit rotor task, a widely used task to assess visuomotor coordination abilities (Harrington et al, 1990;Grafton et al, 1992;Knowlton et al, 2017;Lien et al, 2022).…”

“…In each task session, both the total time until the cursor reached the target and the mean distance between the cursor and target center were recorded in each trial and are referred to as time on target and distance from target, respectively. These two measurements were used to generate behavioral performance indices (Lien et al, 2022).…”

“…In our study, a pursuit rotor task was applied to assess visuomotor learning abilities (Lien et al, 2022). We calculated improvements in performance at the minimum distance from the target point as indices of accuracy and the trial-to-trial variability of distance from the target as indices of stability (Lien et al, 2022).…”

“…In our study, a pursuit rotor task was applied to assess visuomotor learning abilities (Lien et al, 2022). We calculated improvements in performance at the minimum distance from the target point as indices of accuracy and the trial-to-trial variability of distance from the target as indices of stability (Lien et al, 2022). Visuomotor learning performance can be modulated by repetitive cerebellar transcranial magnetic stimulation (rTMS) (Koch, 2010;Lee et al, 2014;Tang et al, 2016;Rastogi et al, 2017).…”