title: Dual-hemisphere transcranial direct current stimulation over primary motor cortex enhances consolidation of a ballistic thumb movement.
abstract: Transcranial direct current stimulation (tDCS) is a noninvasive technique that modulates motor performance and learning. Previous studies have shown that tDCS over the primary motor cortex (M1) can facilitate consolidation of various motor skills. However, the effect of tDCS on consolidation of newly learned ballistic movements remains unknown. The present study tested the hypothesis that tDCS over M1 enhances consolidation of ballistic thumb movements in healthy adults. Twenty-eight healthy subjects participated in an experiment with a single-blind, sham-controlled, between-group design. Fourteen subjects practiced a ballistic movement with their left thumb during dual-hemisphere tDCS. Subjects received 1mA anodal tDCS over the contralateral M1 and 1mA cathodal tDCS over the ipsilateral M1 for 25min during the training session. The remaining 14 subjects underwent identical training sessions, except that dual-hemisphere tDCS was applied for only the first 15s (sham group). All subjects performed the task again at 1h and 24h later. Primary measurements examined improvement in peak acceleration of the ballistic thumb movement at 1h and 24h after stimulation. Improved peak acceleration was significantly greater in the tDCS group (144.2±15.1%) than in the sham group (98.7±9.1%) (P<0.05) at 24h, but not 1h, after stimulation. Thus, dual-hemisphere tDCS over M1 enhanced consolidation of ballistic thumb movement in healthy adults. Dual-hemisphere tDCS over M1 may be useful to improve elemental motor behaviors, such as ballistic movements, in patients with subcortical strokes.
authors.affiliation: Division of Cerebral Integration, National Institute for Physiological Sciences, Aichi 444-8585, Japan; School of Life Sciences, The Graduate University for Advanced Studies, Kanagawa 240-0193, Japan; Department of Rehabilitation, Kawamura Hospital, Gifu 501-3144, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Koyama
authors.affiliation: Laboratory of Psychology, Hamamatsu University School of Medicine, Shizuoka 431-3192, Japan. Electronic address: tanakas@hama-med.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Faculty of Rehabilitation, School of Health Sciences, Fujita Health University, Aichi 470-1192, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Tanabe
authors.affiliation: Division of Cerebral Integration, National Institute for Physiological Sciences, Aichi 444-8585, Japan; School of Life Sciences, The Graduate University for Advanced Studies, Kanagawa 240-0193, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sadato
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement; D018482:Muscle, Skeletal / Q000502:physiology*; D013933:Thumb / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation; D055815:Young Adult
keywords: Ballistic thumb movement; Consolidation; Interhemispheric inhibition; Neurorehabilitation; Transcranial direct current stimulation