Assessment of electric field distribution in anisotropic cortical and subcortical regions under the influence of tDCS

Shahid, Salman and Wen, Peng and Ahfock, Tony (2014) Assessment of electric field distribution in anisotropic cortical and subcortical regions under the influence of tDCS. Bioelectromagnetics , 35 (1). pp. 41-57. ISSN 0197-8462

Abstract

The focus of this study is to estimate the contribution of regional anisotropic conductivity on the spatial distribution of induced electric field across the gray matter (GM), white matter (WM) and sub-cortical regions under transcranial direct current stimulation (tDCS). The assessment was conducted using a passive high-resolution finite element head model with inhomogeneous and variable anisotropic conductivities derived from the diffusion tensor data. Electric field distribution was evaluated across different cortical as well as sub-cortical regions under four bi-cephalic electrode configurations. Results indicate that regional tissue heterogeneity and anisotropy cause the pattern of induced field to vary in orientation and strength when compared to the isotropic scenario. Different electrode montages resulted in distinct distribution patterns with noticeable variations in field strengths. The effect of anisotropy is highly montage dependent and directional conductivity has a more profound effect in defining the strength of the induced field. The inclusion of anisotropy in the GM and sub-cortical regions has a significant effect on the strength and spatial distribution of the induced electric field. Under (C3–Fp2) montage, the inclusion of GM and sub-cortical anisotropy increased the average percentage difference in the electric field strength of brain from 5% (WM anisotropy only) to 34%. In terms of patterns distribution, the topographic errors increased from 9.9% (WM anisotropy only) to 40% across the brain.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2013 Wiley Periodicals, Inc. Published version deposited in accordance with the copyright policy of the publisher. Published online 4 Oct 2013.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Date Deposited: 22 Oct 2013 01:25
Last Modified: 13 May 2015 04:08
Uncontrolled Keywords: anisotropy; tissue electrical conductivity; transcranial direct current stimulation
Fields of Research : 02 Physical Sciences > 0299 Other Physical Sciences > 029903 Medical Physics
11 Medical and Health Sciences > 1109 Neurosciences > 110999 Neurosciences not elsewhere classified
09 Engineering > 0903 Biomedical Engineering > 090303 Biomedical Instrumentation
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: 10.1002/bem.21814
URI: http://eprints.usq.edu.au/id/eprint/24160

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