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Comparative Study
. 1995 Sep 1;487 ( Pt 2)(Pt 2):541-8.
doi: 10.1113/jphysiol.1995.sp020898.

The effect of voluntary contraction on cortico-cortical inhibition in human motor cortex

M C Ridding  1 , J L Taylor, J C Rothwell
Affiliations
Comparative Study

The effect of voluntary contraction on cortico-cortical inhibition in human motor cortex

M C Ridding et al. J Physiol. .

Abstract

1. It has been previously shown that in a relaxed target muscle, at short interstimulus intervals (ISIs) (up to 6 ms) a conditioning subthreshold transcranial magnetic stimulus can cause suppression of the EMG response evoked by a magnetic test stimulus. At longer ISIs (7-15 ms) facilitation of the test response is seen. This type of inhibition has been termed ipsilateral cortico-cortical inhibition. 2. The effect of a minimal tonic contraction on ipsilateral cortico-cortical inhibition has been investigated in the first dorsal interrosseous (FDI). 3. At short ISIs there was significantly less inhibition of the test response during the maintenance of minimal voluntary tonic contraction of the target muscle (FDI). 4. At longer ISIs (7-15 ms) there was significantly less facilitation of the test response during a tonic contraction than during relaxation. 5. Minimal activation of an ipsilateral proximal muscle (biceps) had no significant effect on the degree of inhibition seen in the relaxed target muscle (FDI). 6. We suggest that voluntary drive reduces the excitability of inhibitory circuits in cortical areas that project to the active muscle.

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References

    1. J Neurophysiol. 1987 Nov;58(5):1168-85 - PubMed
    1. J Neurosci. 1988 Sep;8(9):3221-32 - PubMed
    1. Brain. 1991 Feb;114 ( Pt 1B):615-27 - PubMed
    1. J Physiol. 1994 Jun 1;477 ( Pt 2):223-35 - PubMed
    1. Brain. 1993 Jun;116 ( Pt 3):511-25 - PubMed

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