title: Effects of tDCS on motor learning and memory formation: A consensus and critical position paper.
abstract: Motor skills are required for activities of daily living. Transcranial direct current stimulation (tDCS) applied in association with motor skill learning has been investigated as a tool for enhancing training effects in health and disease. Here, we review the published literature investigating whether tDCS can facilitate the acquisition, retention or adaptation of motor skills. Work in multiple laboratories is underway to develop a mechanistic understanding of tDCS effects on different forms of learning and to optimize stimulation protocols. Efforts are required to improve reproducibility and standardization. Overall, reproducibility remains to be fully tested, effect sizes with present techniques vary over a wide range, and the basis of observed inter-individual variability in tDCS effects is incompletely understood. It is recommended that future studies explicitly state in the Methods the exploratory (hypothesis-generating) or hypothesis-driven (confirmatory) nature of the experimental designs. General research practices could be improved with prospective pre-registration of hypothesis-based investigations, more emphasis on the detailed description of methods (including all pertinent details to enable future modeling of induced current and experimental replication), and use of post-publication open data repositories. A checklist is proposed for reporting tDCS investigations in a way that can improve efforts to assess reproducibility.
authors.affiliation: Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Ethan R
authors.initials: ER
authors.lastname: Buch
authors.affiliation: Berenson-Allen Center for Non-Invasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Santarnecchi
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Antal
authors.affiliation: Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Born
authors.affiliation: Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institution, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins Medical Institution, Baltimore, MD, USA.
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Celnik
authors.affiliation: Department of Neurology, University of Leipzig, Leipzig, Germany.
authors.forename: Joseph
authors.initials: J
authors.lastname: Classen
authors.affiliation: Brain Imaging and NeuroStimulation (BINS) Laboratory, Department of Neurology University Medical Center Hamburg-Eppendorf Martinistr, Hamburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Gerloff
authors.affiliation: Human Motor Control Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Hallett
authors.affiliation: Brain Imaging and NeuroStimulation (BINS) Laboratory, Department of Neurology University Medical Center Hamburg-Eppendorf Martinistr, Hamburg, Germany.
authors.forename: Friedhelm C
authors.initials: FC
authors.lastname: Hummel
authors.affiliation: Department of Psychology and Neuroscience, Leibniz Research Center for Working Environment and Human Factors (IfADo), Dortmund, Germany.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Nitsche
authors.affiliation: Berenson-Allen Center for Non-Invasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual-Leone
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Georg-August University, Göttingen, Germany.
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Paulus
authors.affiliation: Department of Neurology, Albert Ludwigs University, Freiburg, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Reis
authors.affiliation: Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK.
authors.forename: Edwin M
authors.initials: EM
authors.lastname: Robertson
authors.affiliation: UCL Institute of Neurology, Queen Square, London, UK.
authors.forename: John C
authors.initials: JC
authors.lastname: Rothwell
authors.affiliation: Department of Psychology, University of Roehampton, London, UK.
authors.forename: Marco
authors.initials: M
authors.lastname: Sandrini
authors.affiliation: Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, NY, USA.
authors.forename: Heidi M
authors.initials: HM
authors.lastname: Schambra
authors.affiliation: Behavioral Neurology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Wassermann
authors.affiliation: Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University, Tübingen, Germany.
authors.forename: Ulf
authors.initials: U
authors.lastname: Ziemann
authors.affiliation: Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA. Electronic address: CohenL@ninds.nih.gov.
authors.forename: Leonardo G
authors.initials: LG
authors.lastname: Cohen
mesh_terms: D006801:Humans; D008568:Memory; D009048:Motor Skills; D065908:Transcranial Direct Current Stimulation / Q000009:adverse effects* / Q000379:methods / Q000592:standards
keywords: Effect-size; Guidelines; Learning; Memory; Motor; Non-invasive brain stimulation; Open Science; tDCS