Decrease of motor cortex excitability following exposure to a 20 Hz magnetic field as generated by a rotating permanent magnet.

Autor: Gallasch E; Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria. Electronic address: eugen.gallasch@medunigraz.at., Rafolt D; Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria., Postruznik M; Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria., Fresnoza S; Department of Psychology, University of Graz, Austria., Christova M; Otto Loewi Research Center, Physiology Section, Medical University of Graz, Austria; Institute of Physiotherapy, University of Applied Sciences FH-Joanneum, Graz, Austria.
Jazyk: angličtina
Zdroj: Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology [Clin Neurophysiol] 2018 Jul; Vol. 129 (7), pp. 1397-1402. Date of Electronic Publication: 2018 Apr 19.
DOI: 10.1016/j.clinph.2018.03.045
Abstrakt: Objectives: Rotation of a static magnet over the motor cortex (MC) generates a transcranial alternating magnetic field (tAMF), and a linked alternating electrical field. The aim of this transcranial magnetic stimulation (TMS) study is to investigate whether such fields are able to influence MC excitability, and whether there are parallels to tACS induced effects.
Methods: Fourteen healthy volunteers received 20 Hz tAMF stimulation over the MC, over the vertex, and 20 Hz tACS over the MC, each with a duration of 15 min. TMS assessments were performed before and after the interventions. Changes in motor evoked potentials (MEP), short interval intra-cortical inhibition (SICI) and intra-cortical facilitation (ICF) were evaluated.
Results: The tACS and the tAMF stimulation over the MC affected cortical excitability in a different way. After tAMF stimulation MEP amplitudes and ICF decreased and the effect of SICI increased. After tACS MEP amplitudes increased and there were no effects on SICI and ICF.
Conclusions: The recorded single and paired pulse MEPs indicate a general decrease of MC excitability following 15 min of tAMF stimulation.
Significance: The effects demonstrate that devices based on rotating magnets are potentially suited to become a novel brain stimulation tool in clinical neurophysiology.
(Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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