The impact of cerebellar transcranial direct current stimulation (tDCS) on learning fine-motor sequences

Abstract

One contribution of 13 to a theme issue 'New frontiers for statistical learning in the cognitive sciences'. The cerebellum has been shown to be important for skill learning, including the learning of motor sequences. We investigated whether cerebellar transcranial direct current stimulation (tDCS) would enhance learning of fine motor sequences. Because the ability to generalize or transfer to novel task variations or circumstances is a crucial goal of real world training, we also examined the effect of tDCS on performance of novel sequences after training. In Study 1, participants received either anodal, cathodal or sham stimulation while simultaneously practising three eight-element key press sequences in a non-repeating, interleaved order. Immediately after sequence practice with concurrent tDCS, a transfer session was given in which participants practised three interleaved novel sequences. No stimulation was given during transfer. An inhibitory effect of cathodal tDCS was found during practice, such that the rate of learning was slowed in comparison to the anodal and sham groups. In Study 2, participants received anodal or sham stimulation and a 24 h delay was added between the practice and transfer sessions to reduce mental fatigue. Although this consolidation period benefitted subsequent transfer for both tDCS groups, anodal tDCS enhanced transfer performance.Together, these studies demonstrate polarity-specific effects on fine motor sequence learning and generalization.This article is part of the themed issue 'New frontiers for statistical learning in the cognitive sciences'.

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

“…cerebellar tDCS led to better knowledge of the sequence when compared to sham. The findings here are in accordance with previous work showing the beneficial effect of anodal cerebellar tDCS on motor sequence learning (Ferrucci et al, 2013;Shimizu et al, 2017) but in contrast to a recent report showing the opposite effect (Ballard et al, 2019). Note that in the latter study, a multi-channel montage was used with a net current of 2mA compared to our protocol with 1mA.…”

“…This effect is however not specific to M1. Other studies showed that anodal stimulation of the cerebellum has a similar effect on sequence learning (Ferrucci et al, 2013;Shimizu et al, 2017), but see (Jongkees et al, 2019).…”

Cerebellar Degeneration Affects Cortico-Cortical Connectivity In Motor Learning Networks

“…Indeed we showed that modulatory effects of these connections were significantly smaller in patients and did not differ between conditions, probably due to the degeneration in cerebellum. Recent studies in healthy controls have shown that modulation of cerebellar activity using transcranial direct current stimulation (tDCS) can influence motor learning behavior (Block and Celnik, 2013;Cantarero et al, 2015;Ehsani et al, 2016;Ferrucci et al, 2013;Galea et al, 2011;Herzfeld et al, 2014;Shimizu et al, 2017). Specifically, this effect has been shown to be polarity specific; anodal tDCS to cerebellum is thought to enhance neuronal excitability and was shown to enhance learning whereas the opposite effect was evident in some studies.…”

The long road of statistical learning research: past, present and future

“…The empirical work of Shimizu et al [22] extends SL research on several important fronts. First, it focuses on visuomotor SL, thereby probing the link between perception and action.…”