title: Transcranial direct current stimulation enhances mu rhythm desynchronization during motor imagery that depends on handedness.
abstract: Transcranial direct current stimulation (tDCS) can modulate the amplitude of event-related desynchronization (ERD) that appears on the electroencephalogram (EEG) during motor imagery. To study the effect of handedness on the modulating effect of tDCS, we compared the difference in tDCS-boosted ERD during dominant and non-dominant hand motor imagery. EEGs were recorded over the left sensorimotor cortex of seven healthy right-handed volunteers, and we measured ERD induced either by dominant or non-dominant hand motor imagery. Ten minutes of anodal tDCS was then used to increase the cortical excitability of the contralateral primary motor cortex (M1), and ERD was measured again. With anodal tDCS, we observed only a small increase in ERD during non-dominant hand motor imagery, whereas the same stimulation induced a prominent increase in ERD during dominant hand motor imagery. This trend was most obvious in the participants who used their dominant hand more frequently. Although our study is preliminary because of a small sample size, these results suggest that the increase in ERD by applying anodal tDCS was stronger on the dominant side than on the non-dominant side. The background excitability of M1 may determine the strength of the effect of anodal tDCS on ERD by hand motor imagery.
authors.affiliation: a Department of Biosciences and Informatics, Faculty of Science and Technology , Keio University , Yokohama , Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Kasuga
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Matsushika
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kasashima-Shindo
authors.forename: Daiki
authors.initials: D
authors.lastname: Kamatani
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Meigen
authors.initials: M
authors.lastname: Liu
authors.forename: Junichi
authors.initials: J
authors.lastname: Ushiba
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004569:Electroencephalography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D010507:Periodicity; D013997:Time Factors; D065908:Transcranial Direct Current Stimulation; D055815:Young Adult
keywords: Electroencephalogram; Event-related desynchronization; Handedness; Motor cortex; Transcranial direct current stimulation