Investigating the technical feasibility of magnetoencephalography during transcranial direct current stimulation

Frontiers in Human Neuroscience

Human Neuroscience

Motofumi Fushimi¹  Masaki Sekino¹  Yuichiro Shirota²  Masato Yumoto³ 

[1] Department of Bioengineering, The Graduate School of Engineering, The University of Tokyo, Tokyo, Japan;Department of Clinical Laboratory, The University of Tokyo Hospital, Tokyo, Japan;Department of Clinical Laboratory, The University of Tokyo Hospital, Tokyo, Japan;Department of Clinical Engineering, Gunma Paz University, Takasaki, Japan;

关键词: MEG;    tDCS;    artifact rejection;    magnetoencephalography;    Maxwell filter;    source modeling;    transcranial direct current stimulation;   

DOI  :  10.3389/fnhum.2023.1270605

 received in 2023-08-01, accepted in 2023-08-28,  发布年份 2023

来源: Frontiers

【 摘 要 】

IntroductionMagnetoencephalography (MEG) can measure weak magnetic fields produced by electrical brain activity. Transcranial direct current stimulation (tDCS) can affect such brain activities. The concurrent application of both, however, is challenging because tDCS presents artifacts on the MEG signal. If brain activity during tDCS can be elucidated by MEG, mechanisms of plasticity-inducing and other effects of tDCS would be more comprehensively understood. We tested the technical feasibility of MEG during tDCS using a phantom that produces an artificial current dipole simulating focal brain activity. An earlier study investigated estimation of a single oscillating phantom dipole during tDCS, and we systematically tested multiple dipole locations with a different MEG device.MethodsA phantom provided by the manufacturer was used to produce current dipoles from 32 locations. For the 32 dipoles, MEG was recorded with and without tDCS. Temporally extended signal space separation (tSSS) was applied for artifact rejection. Current dipole sources were estimated as equivalent current dipoles (ECDs). The ECD modeling quality was assessed using localization error, amplitude error, and goodness of fit (GOF). The ECD modeling performance with and without tDCS, and with and without tSSS was assessed.ResultsMean localization errors of the 32 dipoles were 1.70 ± 0.72 mm (tDCS off, tSSS off, mean ± standard deviation), 6.13 ± 3.32 mm (tDCS on, tSSS off), 1.78 ± 0.83 mm (tDCS off, tSSS on), and 5.73 ± 1.60 mm (tDCS on, tSSS on). Mean GOF findings were, respectively, 92.3, 87.4, 97.5, and 96.7%. Modeling was affected by tDCS and restored by tSSS, but improvement of the localization error was marginal, even with tSSS. Also, the quality was dependent on the dipole location.DiscussionConcurrent tDCS-MEG recording is feasible, especially when tSSS is applied for artifact rejection and when the assumed location of the source of activity is favorable for modeling. More technical studies must be conducted to confirm its feasibility with different source modeling methods and stimulation protocols. Recovery of single-trial activity under tDCS warrants further research.

【 授权许可】

Unknown   
Copyright © 2023 Shirota, Fushimi, Sekino and Yumoto.