Research article summary (published 30 Nov 2005):

Repetitive paired-pulse TMS at I-wave periodicity markedly increases corticospinal excitability: a new technique for modulating synaptic plasticity.

Full Abstract

OBJECTIVE: We hypothesised that facilitatory I-wave interaction set up by paired-pulse transcranial magnetic stimulation delivered with I-wave periodicity (iTMS) may reinforce trans-synaptic events and provide a means for modulating synaptic plasticity and cortical excitability. Our objective was to determine whether prolonged iTMS can increase corticospinal excitability, and whether this form of stimulation can have lasting aftereffects. METHODS: Paired stimuli of equal strength with a 1.5 ms inter-stimulus interval were delivered for 30 min at a rate of 0.2 Hz. Motor threshold and motor evoked potential (MEP) amplitude to single-pulse TMS was compared before and after intervention. RESULTS: Paired-pulse MEP amplitude increased linearly throughout the period of iTMS, and had increased five-fold by the end of the stimulation period. Single-pulse MEP amplitude was increased a mean of four-fold for 10 min after stimulation. Motor threshold was unaffected. CONCLUSIONS: iTMS is an effective method for increasing excitability of the human motor cortex, and probably acts by increasing synaptic efficacy. SIGNIFICANCE: Reinforcement of trans-synaptic events by iTMS may provide a means to investigate and modulate synaptic plasticity in the brain.

Author information

Author/s: Thickbroom, Gary W (GW); Byrnes, Michelle L (ML); Edwards, Dylan J (DJ); Mastaglia, Frank L (FL);

Affiliation: Centre for Neuromuscular and Neurological Disorders, Queen Elizabeth II Medical Centre, University of Western Australia, Perth, Nedlands, WA 6009, Australia. gthickbr(-atsign-)cyllene.uwa.edu.au

Journal and publication information

Publication Type: Clinical Trial; Comparative Study; Journal Article

Journal: Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology (Clin Neurophysiol), published in Netherlands. (Language: eng)

Reference: 2006-Jan; vol 117 (issue 1) : pp 61-6

Dates: Created 2006/01/23; Completed 2006/04/12; Revised 2008/09/10;

PMID: 16326137, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult Differential Threshold - radiation effects Dose-Response Relationship, Radiation Electromyography - methods Evoked Potentials, Motor - physiology; radiation effects Female Humans Male Motor Cortex - physiology; radiation effects

Motor Cortex - physiology; radiation effects Muscle, Skeletal - physiology Neural Inhibition - physiology; radiation effects Neuronal Plasticity - radiation effects Periodicity Pyramidal Tracts - physiology; radiation effects Reaction Time - physiology; radiation effects Time Factors Transcranial Magnetic Stimulation

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