title: Effect of transcranial static magnetic field stimulation over the sensorimotor cortex on somatosensory evoked potentials in humans.
abstract: BACKGROUND
  The motor cortex in the human brain can be modulated by the application of transcranial static magnetic field stimulation (tSMS) through the scalp. However, the effect of tSMS on the excitability of the primary somatosensory cortex (S1) in humans has never been examined.
  
  
  OBJECTIVE
  This study was performed to investigate the possibility of non-invasive modulation of S1 excitability by the application of tSMS in healthy humans.
  
  
  METHODS
  tSMS and sham stimulation over the sensorimotor cortex were applied to 10 subjects for periods of 10 and 15 min. Somatosensory evoked potentials (SEPs) following right median nerve stimulation were recorded before and immediately after, 5 min after, and 10 min after tSMS from sites C3' and F3 of the international 10-20 system of electrode placement. In another session, SEPs were recorded from 6 of the 10 subjects every 3 min during 15 min of tSMS.
  
  
  RESULTS
  Amplitudes of the N20 component of SEPs at C3' significantly decreased immediately after 10 and 15 min of tSMS by up to 20%, returning to baseline by 10 min after intervention. tSMS applied while recording SEPs every 3 min and sham stimulation had no effect on SEP.
  
  
  CONCLUSIONS
  tSMS is able to modulate cortical somatosensory processing in humans, and thus might be a useful tool for inducing plasticity in cortical somatosensory processing. Lack of change in the amplitude of SEPs with tSMS implies that use of peripheral nerve stimulation to cause SEPs antagonizes alteration of the function of membrane ion channels during exposure to static magnetic fields.
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata 950-1398, Japan. Electronic address: kirimoto@nuhw.ac.jp.
authors.forename: Hikari
authors.initials: H
authors.lastname: Kirimoto
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata 950-1398, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tamaki
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata 950-1398, Japan; Graduate School of Health and Welfare, Niigata University of Health and Welfare, Niigata, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata 950-1398, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sugawara
authors.affiliation: Occupational Therapy Course, School of Allied Health Sciences, Kitasato University, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata 950-1398, Japan.
authors.forename: Mineo
authors.initials: M
authors.lastname: Oyama
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata 950-1398, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Onishi
mesh_terms: D000328:Adult; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology; D066191:Sensorimotor Cortex / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Non-invasive brain stimulation; Somatosensory evoked potentials; Transcranial static magnetic field stimulation