title: Behavioural and neurofunctional impact of transcranial direct current stimulation on somatosensory learning.
abstract: We investigated the effect of repeated delivery of anodal transcranial direct current stimulation (tDCS) on somatosensory performance and long-term learning. Over the course of five days, tDCS was applied to the primary somatosensory cortex (S1) by means of neuronavigation employing magnetencephalography (MEG). Compared to its sham application, tDCS promoted tactile learning by reducing the two-point discrimination threshold assessed by the grating orientation task (GOT) primarily by affecting intersessional changes in performance. These results were accompanied by alterations in the neurofunctional organization of the brain, as revealed by functional magnetic resonance imaging conducted prior to the study, at the fifth day of tDCS delivery and four weeks after the last application of tDCS. A decrease in activation at the primary site of anodal tDCS delivery in the left S1 along retention of superior tactile acuity was observed at follow-up four weeks after the application of tDCS. Thus, we demonstrate long-term effects that repeated tDCS imposes on somatosensory functioning. This is the first study to provide insight into the mode of operation of tDCS on the brain's response to long-term perceptual learning, adding an important piece of evidence from the domain of non-invasive brain stimulation to show that functional changes detectable by fMRI in primary sensory cortices participate in perceptual learning.
authors.affiliation: Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany.|Department of Pediatrics, HELIOS Children's Hospital Wuppertal, Witten/Herdecke University, Wuppertal, Germany.
authors.forename: Raphael
authors.initials: R
authors.lastname: Hilgenstock
authors.affiliation: Department of Biological and Clinical Psychology, Friedrich Schiller University, Jena, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weiss
authors.affiliation: Brain Imaging Center, Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Huonker
authors.affiliation: Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany.|Center for Sepsis Control and Care, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
authors.forename: Otto W
authors.initials: OW
authors.lastname: Witte
mesh_terms: D000293:Adolescent; D000328:Adult; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D013003:Somatosensory Cortex / Q000502:physiology*; D014110:Touch / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D055815:Young Adult
keywords: (repeated) transcranial direct current stimulation; longitudinal fMRI; neuronavigation; perceptual learning; somatosensory learning