title: Motor imagery of voluntary muscle relaxation induces temporal reduction of corticospinal excitability.
abstract: Voluntary muscle relaxation is an "active process" requiring cortical activation. However, cortical activation during motor imagery of muscle relaxation has not been well understood. The purpose of this study was to clarify time-dependent changes in corticospinal excitability during the imagery of muscle relaxation. Ten participants imagined volitional muscle relaxation from an imagined pinching with their right index finger and thumb in response to an auditory cue. Transcranial magnetic stimulation was applied at the left primary motor area of the first dorsal interosseous (FDI) muscle at different time intervals after the auditory cue. Motor evoked potentials (MEPs) were recorded from the right hand and forearm muscles. The MEP amplitudes of the FDI and the synergist temporally decreased after the auditory cue as compared with those present in the resting condition. Our finding indicates that motor imagery of muscle relaxation induces a temporal reduction of the corticospinal excitability related to the targeted muscle.
authors.affiliation: Faculty of Sport Sciences, Waseda University, Tokorozawa, Japan; Japan Society for the Promotion of Science, Tokyo, Japan. Electronic address: kouki-nagoya@fuji.waseda.jp.
authors.forename: Kouki
authors.initials: K
authors.lastname: Kato
authors.affiliation: Graduate of Sport Sciences, Waseda University, Tokorozawa, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Watanabe
authors.affiliation: College of Economics, Nihon University, Tokyo, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Muraoka
authors.affiliation: Faculty of Sport Sciences, Waseda University, Tokorozawa, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kanosue
mesh_terms: D000328:Adult; D004576:Electromyography; D019054:Evoked Potentials, Motor; D005260:Female; D006225:Hand / Q000502:physiology; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement; D009126:Muscle Relaxation; D018482:Muscle, Skeletal / Q000502:physiology*; D011712:Pyramidal Tracts / Q000502:physiology*; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Inhibition; MEP; Motor imagery; Relaxation; TMS