Beneficial effects of cerebellar tDCS on motor learning are associated with altered putamen-cerebellar connectivity: A simultaneous tDCS-fMRI study

Liebrand, Matthias; Karabanov, Anke; Antonenko, Daria; Flöel, Agnes; Siebner, Hartwig R.; Classen, Joseph; Krämer, Ulrike M.; Tzvi, Elinor · 2020 · DOAJ

DOI: 10.1016/j.neuroimage.2020.117363

archive: archived pipeline: cataloged verified

Get this paper ↗ (DOI — opens at the source; we link to it, we don't host it)

Summary

This study investigates the neural mechanisms underlying motor learning enhancements induced by transcranial direct current stimulation (tDCS). While previous research established that anodal tDCS applied to the primary motor cortex (M1) or cerebellum improves motor sequence learning, the specific neural correlates and network connectivity changes driving these behavioral improvements remained unclear. The authors aimed to elucidate how tDCS modulates activity and effective connectivity within the cortico-striato-cerebellar learning network by simultaneously recording functional magnetic resonance imaging (fMRI) during stimulation. The experimental design involved 25 healthy participants who underwent three separate sessions: anodal tDCS over the right cerebellum, anodal tDCS over the left M1, or sham stimulation. During each session, participants performed a serial reaction time task (SRTT) inside the MRI scanner to learn an 8-element motor sequence. Behavioral performance was assessed via reaction times and a post-training sequence completion task. The researchers analyzed fMRI data using general linear modeling to identify changes in regional brain activity and employed dynamic causal modeling (DCM) to assess changes in effective connectivity between key nodes: left M1, left putamen, left supplementary motor area, left premotor cortex, and right cerebellum. Behavioral results demonstrated that right cerebellar tDCS significantly enhanced sequence learning compared to sham, evidenced by faster reaction times during the task and superior performance in the post-training completion task. In contrast, left M1 tDCS did not produce significant group-level improvements in learning, although individual variability in activation patterns correlated with performance. Neuroimaging analysis revealed that cerebellar tDCS increased learning-specific activity in right M1, left cerebellum lobule VI, left inferior frontal gyrus, and right inferior parietal lobule. Crucially, DCM analysis showed that cerebellar tDCS specifically altered connectivity within the learning network. It decreased the negative modulation of the connection from the putamen to the cerebellum during sequence learning, effectively reducing the inhibition of the cerebellum. This connectivity change was specific to the learning condition and was not observed with M1 tDCS or sham stimulation. These findings provide mechanistic insight into how cerebellar tDCS facilitates motor learning. The study suggests that the beneficial effects of cerebellar stimulation are linked to a specific reduction in inhibitory input from the putamen to the cerebellum, thereby enhancing cerebellar engagement during the early stages of learning. This distinction highlights different roles for M1 and cerebellar stimulation in the motor learning network. The results imply that optimizing motor rehabilitation protocols may require targeting specific connectivity patterns rather than merely increasing regional excitability, supporting the potential of cerebellar tDCS as a targeted intervention for enhancing motor skill acquisition.

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed.

Summary generated by qwen3.6-27b-prismaquant on 2026-06-26; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• automaticity skill acquisition