Original Research ARTICLE
A Preliminary Comparison of Motor Learning Across Different Noninvasive Brain Stimulation Paradigms Shows No Consistent Modulations
- 1National Institutes of Health (NIH), United States
- 2Centro de Enseñanza Superior Alberta Giménez, Universidad Pontificia Comillas, Spain
- 3University of A Coruña, Spain
- 4University of Southern California, United States
- 5St George's, University of London, United Kingdom
- 6The London Clinic, United Kingdom
- 7University of Roehampton, United Kingdom
- 8Fukushima Medical University, Japan
Noninvasive brain stimulation (NIBS) has been widely explored as a way to safely modulate brain activity and alter human performance for nearly three decades. Research using NIBS has grown exponentially within the last decade with promising results across a variety of clinical and healthy populations. However, recent work has shown high inter-individual variability and a lack of reproducibility of previous results. Here, we conducted a small preliminary study to explore the effects of three of the most commonly used excitatory NIBS paradigms over the primary motor cortex (M1) on motor learning (Sequential Visuomotor Isometric Pinch Force Tracking Task) and secondarily relate changes in motor learning to changes in cortical excitability (MEP amplitude and SICI). We compared anodal transcranial direct current stimulation (tDCS), paired associative stimulation (PAS25), and intermittent theta burst stimulation (iTBS), along with a sham tDCS control condition. Stimulation was applied prior to motor learning. Participants (n=28) were randomized into one of the four groups and were trained on a skilled motor task. Motor learning was measured immediately after training (online), one day after training (consolidation), and one week after training (retention). We did not find consistent differential effects on motor learning or cortical excitability across groups. Within the boundaries of our small sample sizes, we then assessed effect sizes across the NIBS groups that could help power future studies. These results, which require replication with larger samples, are consistent with previous reports of small and variable effect sizes of these interventions on motor learning.
Keywords: non-invasive brain stimulation, motor learning, transcranial direct current stimulation (tDCS), paired associative stimulation (PAS), Theta burst stimulation (TBS), power analysis
Received: 07 Dec 2017;
Accepted: 03 Apr 2018.
Edited by:Gregor Thut, University of Glasgow, United Kingdom
Reviewed by:Martin V. Sale, The University of Queensland, Australia
Sara Tremblay, University College London, United Kingdom
Copyright: © 2018 López-Alonso, Liew, FERNANDEZ-DEL-OLMO, Cheeran, Sandrini, Abe and Cohen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Dr. Virginia López-Alonso, National Institutes of Health (NIH), Bethesda, United States, firstname.lastname@example.org
Dr. Leonardo G. Cohen, National Institutes of Health (NIH), Bethesda, United States, email@example.com