title: Origin of facilitation in repetitive, 1.5ms interval, paired pulse transcranial magnetic stimulation (rPPS) of the human motor cortex.
abstract: OBJECTIVE
  Repetitive paired-pulse TMS (rPPS) given at an interstimulus interval (ISI) of 1.5 ms has been reported to induce a lasting motor evoked potential (MEP) facilitation. This after-effect was considered to be a cortical event because F-waves were not affected by the same rPPS. To confirm its cortical facilitation, we compared the after-effects of rPPS on MEPs to single pulse TMS over the motor cortex (motor cortical MEPs) with those to brainstem stimulation (brainstem MEPs).
  
  
  METHODS
  Subjects were 10 healthy volunteers. Suprathreshold paired-pulse TMS at an ISI of 1.5 ms was applied to the motor cortex for 30 min at a rate of 0.2 Hz. After intervention, we measured motor cortical MEPs for 30 min. We also studied brainstem MEPs in five subjects.
  
  
  RESULTS
  Motor cortical MEPs were facilitated to about 190% of baseline (p<0.001) for 10 min post rPPS intervention and returned to the baseline at 10-15 min post intervention. Brainstem MEPs were not affected by the intervention.
  
  
  CONCLUSIONS
  The facilitation of MEPs after rPPS at an interval of 1.5 ms occurs at the motor cortex.
  
  
  CONCLUSIONS
  rPPS at an interval of 1.5 ms is an effective method for increasing motor cortical excitability.
authors: Department of Neurology, Division of Neuroscience, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Tokyo, Japan. mhamada-tky@umin.ac.jp
authors: Masashi
authors: M
authors: Hamada
authors: Ritsuko
authors: R
authors: Hanajima
authors: Yasuo
authors: Y
authors: Terao
authors: Noritoshi
authors: N
authors: Arai
authors: Toshiaki
authors: T
authors: Furubayashi
authors: Satomi
authors: S
authors: Inomata-Terada
authors: Akihiro
authors: A
authors: Yugeta
authors: Hideyuki
authors: H
authors: Matsumoto
authors: Yuichiro
authors: Y
authors: Shirota
authors: Yoshikazu
authors: Y
authors: Ugawa
mesh_terms: D000328:Adult; D001933:Brain Stem / Q000502:physiology; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology; D050781:Transcranial Magnetic Stimulation