Modulation of intracortical facilitatory circuits of the human primary motor cortex by digital nerve stimulation.

Full Abstract

We investigated the effect of electrical digit stimulation on two different intracortical facilitatory phenomena. Paired-pulse transcranial magnetic stimuli (TMS) with different conditioning stimulus (CS) intensities were applied over the primary motor cortex (M1). Electromyographic (EMG) recordings were made from the relaxed right abductor digiti minimi muscle (ADM). The effect of preceding sensory stimulation applied to the ipsilateral digit V on the conditioning magnetic stimulus was examined. Changing the CS intensity affected the influence of peripheral electrical stimulation on motor evoked potential (MEP) amplitudes evoked by paired pulse TMS. Inhibition induced by ipsilateral digit stimulation was strongest with the lowest CS intensity if MEP amplitudes were evoked by a subthreshold CS followed by a suprathreshold test stimulus (TS) at an interstimulus interval (ISI) of 10 ms. In contrast, inhibition induced by digit stimulation in a paired-pulse paradigm with a suprathreshold first and a subthreshold second stimulus at ISI of 1.5 ms was strongest with the highest CS intensity. These findings suggest that appropriately timed peripheral electrical stimuli differentially modulate facilitatory interactions in the primary motor cortex. They further support the hypothesis that intracortical facilitation (ICF) and short-interval intracortical facilitation (SICF) are evoked through different mechanisms.

Author information

Author/s: Zittel, Simone (S); Bäumer, Tobias (T); Liepert, Joachim (J);

Affiliation: Department of Neurology, University Medical Center Eppendorf, Martinistr 52, 20246 Hamburg, Germany. szittel(-atsign-)uke.uni-hamburg.de

Journal and publication information

Publication Type: Journal Article

Journal: Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale (Exp Brain Res), published in Germany. (Language: eng)

Reference: 2007-Jan; vol 176 (issue 3) : pp 425-31

Dates: Created 2006/12/20; Completed 2007/08/15; Revised 2008/02/15;

PMID: 16951961, 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.

Comments and Corrections

ErratumIn: Exp Brain Res. 2007 Jan;176(3):538.

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