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Modulation of soleus H reflex by spinal DC stimulation in humans.

Abstract

Transcranial direct current stimulation (tDCS) of the human motor cortex induces changes in excitability within cortical and spinal circuits that occur during and after the stimulation. Recently, transcutaneous spinal direct current stimulation (tsDCS) has been shown to modulate spinal conduction properties, as assessed by somatosensory-evoked potentials, and transynaptic properties of the spinal neurons, as tested by postactivation depression of the H reflex or by the RIII nociceptive component of the flexion reflex in the lower limb. To further explore tsDCS-induced plastic changes in spinal excitability, we examined, in a double-blind crossover randomized study, the stimulus-response curves of the soleus H reflex before, during, at current offset and 15 min after anodal, cathodal, and sham tsDCS delivered at the Th11 level (2.5 mA, 15 min, 0.071 mA/cm(2), 0.064 C/cm(2)) in 17 healthy subjects. Anodal tsDCS induced a progressive leftward shift of the recruitment curve of the soleus H reflex during the stimulation; the effects persisted for at least 15 min after current offset. In contrast, both cathodal and sham tsDCS had no significant effects. This exploratory study provides further evidence for the use of tsDCS as an expedient, noninvasive tool to induce long-lasting plastic changes in spinal circuitry. Increased spinal excitability after anodal tsDCS may have potential for spinal neuromodulation in patients with central nervous system lesions.

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  • FREE Publisher Full Text
  • Authors

    Lamy JC, Ho C, Badel A, Arrigo RT, Boakye M

    Source

    Journal of neurophysiology 108:3 2012 Aug 1 pg 906-14

    MeSH

    Adult
    Evoked Potentials, Motor
    Evoked Potentials, Somatosensory
    Female
    H-Reflex
    Humans
    Male
    Muscle, Skeletal
    Recruitment, Neurophysiological
    Transcutaneous Electric Nerve Stimulation
    Young Adult

    Pub Type(s)

    Journal Article
    Randomized Controlled Trial
    Research Support, U.S. Gov't, Non-P.H.S.

    Language

    eng

    PubMed ID

    22623482