title: Effect of Paired-Pulse Electrical Stimulation on the Activity of Cortical Circuits.
abstract: OBJECTIVE
  We investigated the transient effect of short-duration paired-pulse electrical stimulation (ppES) on corticospinal excitability and the after-effect of long-duration ppES on excitability, short-latency afferent inhibition (SAI), and afferent facilitation (AF).
  
  
  METHODS
  A total of 28 healthy subjects participated in two different experiments. In Experiment 1, motor-evoked potentials (MEPs) were measured in the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles before and immediately after short-duration ppES (5 s) at various inter-pulse intervals (2, 3, 4, 5, 6, 7, 10, 15, 20, and 30 ms). In Experiment 2, MEPs, SAI, and AF were measured before, immediately, and 20 and 40 min after long-duration ppES (20 min, inter-pulse interval of 5 and 15 ms) and peripheral electrical stimulation (20 min, 10 and 20 Hz).
  
  
  RESULTS
  Short-duration ppES with inter-pulse intervals of 5 and 20 ms significantly increased MEP measured in APB but not in ADM. Long-duration ppES with an inter-pulse interval of 5 ms significantly decreased SAI but not MEPs in APB. In contrast, long-duration ppES did not affect ADM.
  
  
  CONCLUSIONS
  The afferent inputs induced by ppES-5 ms were effective for transiently increasing MEP and sustaining SAI reduction.
authors.affiliation: Department of Physical Therapy, Niigata University of Health and WelfareNiigata, Japan; Institute for Human Movement and Medical Sciences, Niigata University of Health and WelfareNiigata, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Physical Therapy, Niigata University of Health and WelfareNiigata, Japan; Institute for Human Movement and Medical Sciences, Niigata University of Health and WelfareNiigata, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Onishi
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Miyaguchi
authors.affiliation: Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kotan
authors.affiliation: Graduate School of Medicine, Kyoto University Kyoto, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Fujimoto
keywords: corticospinal excitability; corticospinal pathways; motor cortex; peripheral electrical stimulation; short-latency afferent inhibition