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

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Gallasch E, Rafolt D, Postruznik M, Fresnoza S, Christova M. · 2018

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After 15 minutes of 20 Hz tAMF stimulation, motor cortex excitability decreased, with reduced MEP amplitudes and ICF and increased SICI.

Plain English Summary

Summary written for general audiences

Fourteen healthy volunteers received 20 Hz tAMF stimulation over the motor cortex, over the vertex, and 20 Hz tACS over the motor cortex, each for 15 minutes. TMS assessments were performed before and after the interventions to evaluate changes in MEP, SICI, and ICF. After tAMF stimulation, MEP amplitudes and ICF decreased while the effect of SICI increased. After tACS stimulation, MEP amplitudes increased with no effects on SICI and ICF.

Why This Matters

The study aimed to investigate whether such fields could influence motor cortex excitability and whether there were parallels to tACS-induced effects. The tACS and tAMF stimulations over the motor cortex affected cortical excitability in different ways.

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 20 Hz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 20 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study. The study examined exposure from: 20 Hz Duration: 15 min

Study Details

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.

Fourteen healthy volunteers received 20 Hz tAMF stimulation over the MC, over the vertex, and 20 Hz ...

The tACS and the tAMF stimulation over the MC affected cortical excitability in a different way. Aft...

The recorded single and paired pulse MEPs indicate a general decrease of MC excitability following 15 min of tAMF stimulation.

Cite This Study
Gallasch E, Rafolt D, Postruznik M, Fresnoza S, Christova M. (2018). Decrease of motor cortex excitability following exposure to a 20 Hz magnetic field as generated by a rotating permanent magnet. Clin Neurophysiol. 129(7):1397-1402, 2018.
Show BibTeX
@article{e_2018_decrease_of_motor_cortex_1744,
  author = {Gallasch E and Rafolt D and Postruznik M and Fresnoza S and Christova M.},
  title = {Decrease of motor cortex excitability following exposure to a 20 Hz magnetic field as generated by a rotating permanent magnet.},
  year = {2018},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/29729595/},
}
PubMed: 29729595

Cited By (10 papers)

Quick Questions About This Study

Fourteen healthy volunteers received 20 Hz tAMF stimulation over the motor cortex, over the vertex, and 20 Hz tACS over the motor cortex, each for 15 minutes, with TMS assessments before and after.
After tAMF stimulation, MEP amplitudes and ICF decreased while the effect of SICI increased, indicating a general decrease in motor cortex excitability.
After tACS stimulation, MEP amplitudes increased with no effects on SICI and ICF.
The tACS and tAMF stimulations over the motor cortex affected cortical excitability in different ways, with tAMF decreasing MEP and ICF and increasing SICI, while tACS increased MEP with no effects on SICI and ICF.
The study aimed to investigate whether such fields could influence motor cortex excitability and whether there were parallels to tACS-induced effects.