Thresholds and mechanisms of human magnetophosphene perception induced by low frequency sinusoidal magnetic fields.

Autor: Legros A; Human Threshold Research Group, Lawson Health Research Institute, London, ON, Canada; Departments of Medical Biophysics and Medical Imaging Western University, London, ON, Canada; School of Kinesiology, Western University, London, ON, Canada; EuroMov Digital Health in Motion, University of Montpellier and IMT Mines Ales, Montpellier, France. Electronic address: alegros@lawsonimaging.ca., Nissi J; Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland., Laakso I; Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland., Duprez J; Univ Rennes, INSERM, LTSI - U1099, F-35000, France., Kavet R; Kavet Consulting LLC, Oakland, CA, USA., Modolo J; Human Threshold Research Group, Lawson Health Research Institute, London, ON, Canada; Univ Rennes, INSERM, LTSI - U1099, F-35000, France.
Jazyk: angličtina
Zdroj: Brain stimulation [Brain Stimul] 2024 May-Jun; Vol. 17 (3), pp. 668-675. Date of Electronic Publication: 2024 May 11.
DOI: 10.1016/j.brs.2024.05.004
Abstrakt: Background: Virtually everyone is exposed to power-frequency MF (50/60 Hz), inducing in our body electric fields and currents, potentially modulating brain function. MF-induced electric fields within the central nervous system can generate flickering visual perceptions (magnetophosphenes), which form the basis of international MF exposure guidelines and recommendations protecting workers and the general public. However, magnetophosphene perception thresholds were estimated 40 years ago in a small, unreplicated study with significant uncertainties and leaving open the question of the involved interaction site.
Methods: We used a stimulation modality termed transcranial alternating magnetic stimulation (tAMS), delivering in situ sinusoidal electric fields comparable to transcranial alternating current stimulation (tACS). Magnetophosphene perception was quantified in 81 volunteers exposed to MF (eye or occipital exposure) between 0 and 50 mT at frequencies of 20, 50, 60 and 100 Hz.
Results: Reliable magnetophosphene perception was induced with tAMS without any scalp sensation, a major advantage as compared to tACS. Frequency-dependent thresholds were quantified using binary logistic regressions hence allowing to establish condition dependent probabilities of perception. Results support an interaction between induced current density and retinal rod cells.
Conclusion: Beyond fundamental and immediate implications for international safety guidelines, and for identifying the interaction site underlying phosphene perception (ubiquitous in tACS experiments), our results support exploring the potential of tAMS for the differential diagnosis of retinal disorders and neuromodulation therapy.
Competing Interests: Declaration of competing interest On the behalf of all the co-authors, I declare that neither me nor the co-authors have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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