title: Effects of unilateral voluntary movement on motor imagery of the contralateral limb.
abstract: OBJECTIVE
  To investigate whether unilateral voluntary movement affects voluntary drive of motor imagery for the contralateral limb.
  
  
  METHODS
  The subjects were asked to maintain the left index-finger movements with different directions (abduction and adduction, 5% of maximum voluntary contraction; MVC) and with different force levels (10% and 25% MVC). Under these conditions, transcranial magnetic stimulation was applied over the left motor cortex to record motor evoked potential (MEP) from the right first dorsal interosseous muscle with or without motor imagery of the right index-finger abduction.
  
  
  RESULTS
  Voluntary movement of the left index finger with isodirection, but not mirrored direction, to the imagined movement reduced the MEP enhancement induced by motor imagery. MEP was gradually increased depending on increment of the force level on the left side, while the motor imagery-induced MEP enhancement was consequently reduced.
  
  
  CONCLUSIONS
  Enhancement of the motor cortex excitability driven by motor imagery of the contralateral limb is interfered with by isodirection and forceful movement of the ipsilateral limb, which may be due to an increase in the transcallosal inhibitory effects.
  
  
  CONCLUSIONS
  Using motor imagery as a therapeutic tool, the voluntary movements on the other side of the body should be taken into account.
authors.affiliation: Department of Physiology, Graduate School of Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan; Center for Advanced Practice and Research of Rehabilitation, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. Electronic address: liangnan@hiroshima-u.ac.jp.
authors.forename: Nan
authors.initials: N
authors.lastname: Liang
authors.affiliation: Department of Human Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashihiroshima 739-8521, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Funase
authors.affiliation: Department of Human Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashihiroshima 739-8521, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Narita
authors.affiliation: Center for Advanced Practice and Research of Rehabilitation, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan; Department of Health and Sports Medical Sciences, Graduate School of Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Physiology, Graduate School of Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan; Center for Advanced Practice and Research of Rehabilitation, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Kanji
authors.initials: K
authors.lastname: Matsukawa
authors.affiliation: Department of Physiology, Graduate School of Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kasai
mesh_terms: D000328:Adult; D003337:Corpus Callosum / Q000502:physiology; D004328:Drive; D004576:Electromyography; D005121:Extremities / Q000502:physiology; D005260:Female; D005385:Fingers / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult