title: Effects of different electrical brain stimulation protocols on subcomponents of motor skill learning.
abstract: BACKGROUND
  Noninvasive electrical brain stimulation (NEBS) with transcranial direct current (tDCS) or random noise stimulation (tRNS) applied to the primary motor cortex (M1) can augment motor learning.
  
  
  OBJECTIVE
  We tested whether different types of stimulation alter particular aspects of learning a tracing task over three consecutive days, namely skill acquisition (online/within session effects) or consolidation (offline/between session effects).
  
  
  METHODS
  Motor training on a tracing task over three consecutive days was combined with different types and montages of stimulation (tDCS, tRNS).
  
  
  RESULTS
  Unilateral M1 stimulation using tRNS as well as unilateral and bilateral M1 tDCS all enhanced motor skill learning compared to sham stimulation. In all groups, this appeared to be driven by online effects without an additional offline effect. Unilateral tDCS resulted in large skill gains immediately following the onset of stimulation, while tRNS exerted more gradual effects. Control stimulation of the right temporal lobe did not enhance skill learning relative to sham.
  
  
  CONCLUSIONS
  The mechanisms of action of tDCS and tRNS are likely different. Hence, the time course of skill improvement within sessions could point to specific and temporally distinct interactions with the physiological process of motor skill learning. Exploring the parameters of NEBS on different tasks and in patients with brain injury will allow us to maximize the benefits of NEBS for neurorehabilitation.
authors.affiliation: Department of Neurology, Albert-Ludwigs-University Freiburg, Germany; Faculty of Behavioral and Social Sciences, University of Groningen, The Netherlands; Institute of Cognitive Neuroscience, University College London, United Kingdom.
authors.forename: George
authors.initials: G
authors.lastname: Prichard
authors.affiliation: Department of Neurology, Albert-Ludwigs-University Freiburg, Germany.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Weiller
authors.affiliation: Department of Neurology, Albert-Ludwigs-University Freiburg, Germany.
authors.forename: Brita
authors.initials: B
authors.lastname: Fritsch
authors.affiliation: Department of Neurology, Albert-Ludwigs-University Freiburg, Germany. Electronic address: janine.reis@uniklinik-freiburg.de.
authors.forename: Janine
authors.initials: J
authors.lastname: Reis
mesh_terms: D000328:Adult; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D013997:Time Factors; D065908:Transcranial Direct Current Stimulation; D055815:Young Adult
keywords: Brain stimulation; tDCS; tRNS