Dose-response of tDCS effects on motor learning and cortical excitability: a preregistered studyuse asterix (*) to get italics

Gavin Hsu, Dylan J. Edwards, Leonardo G. Cohen, Lucas C. ParraPlease use the format "First name initials family name" as in "Marie S. Curie, Niels H. D. Bohr, Albert Einstein, John R. R. Tolkien, Donna T. Strickland"

2024

<p>Neuromodulatory effects of transcranial direct current stimulation (tDCS) on the primary motor cortex (M1) have been reported in terms of changes in corticospinal excitability using motor evoked potentials (MEPs), as well as behavioral effects during motor skill learning. While both effects are thought to be mediated by synaptic plasticity, empirical evidence of a common neural substrate is lacking. Complicating matters, the effects are relatively small, leading to mixed results, or even reversing effects when applying currents up to 2mA. In this ongoing preregistered study we aim to determine the dose-response of tDCS on cortical excitability and motor skill learning at higher current intensities in humans. In a double-blind, sham-controlled, counterbalanced design, 120 healthy subjects are assigned to one of three groups (N=40 each), receiving either 4mA, 6mA, or 0mA tDCS. tDCS is applied concurrently targeting M1, while the subject performs a 12-minute long explicit sequence learning task using their left hand. Using transcranial magnetic stimulation (TMS), motor evoked potentials (MEPs) are measured on the left first dorsal interosseus (FDI) immediately before and after the task. TMS-evoked potentials (TEPs) are recorded simultaneously with MEPs using electroencephalography (EEG) as a measure of cortico-cortical excitability. The trial is powered to test for a monotonic or non-monotonic dose-response relationship between tDCS intensity and motor skill performance as well as change in MEP amplitude. Correlation between physiological and behavioral effects would provide support for the notion that these stimulation effects share a common neural substrate. More importantly, this trial aims to establish whether tDCS can have robust effects on motor skill learning.</p>

tDCS, TMS, EEG, neuromodulation, motor learning, synaptic plasticity

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Engineering, Life Sciences

Kate Watkins [kate.watkins@psy.ox.ac.uk] suggested: I am sorry but I have been unwell and am unable to review this manuscript. , Kate Watkins [kate.watkins@psy.ox.ac.uk] suggested: You could try my previous student who is now faculty at Bangor , Kate Watkins [kate.watkins@psy.ox.ac.uk] suggested: Charlie Wiltshire c.wiltshire@bangor.ac.uk, Charlie Wiltshire suggested: Harriet Smith: harriet.j.smith@ucl.ac.uk , Charlie Wiltshire suggested: Daniel Lametti: https://psychology.acadiau.ca/daniel-lametti.html

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2024-01-11 00:11:23

Christina Artemenko