Optimizing Transcranial Direct Current Stimulation Montage for Visual Cortex Targeting: A Computational Modeling Study
Minseo Park
Korean Minjok Leadership Academy, Hoengseong-gun, S.Korea
Publication date: July 10, 2026
Korean Minjok Leadership Academy, Hoengseong-gun, S.Korea
Publication date: July 10, 2026
DOI: http://doi.org/10.34614/JIYRC2026I15
ABSTRACT
This study systematically compares five widely used tDCS electrode montages for visual cortex stimulation using finite element modeling. Five electrode configurations (50mmx50mm electrode, 2mA) were simulated on the Ernie head model at SimNIBS v4.5. Then, electric field distribution was calculated using Laplace equation and finite element method, and evaluated by measure five metrics: mean visual cortex E-field (E_VC), mean primary visual cortex E-field (E_V1), targeting ratio (TR), specificity index (SI), and spatial focality (F75). Among five protocols, protocol 4 (O1-Cz)—Cz-return electrode montage—showed superior targeting ratio and specificity index than Fp-return electrode montage, while showing comparable visual cortex electric field intensity. Return electrode placement was identified as a deterministic factor for visual cortex stimulation selectivity. The O1→Cz montage provides the optimal balance between field intensity, selectivity, and focality, and is identified as optimal electrode montage over commonly used fronto-occipital configurations for visual cortex tDCS.
This study systematically compares five widely used tDCS electrode montages for visual cortex stimulation using finite element modeling. Five electrode configurations (50mmx50mm electrode, 2mA) were simulated on the Ernie head model at SimNIBS v4.5. Then, electric field distribution was calculated using Laplace equation and finite element method, and evaluated by measure five metrics: mean visual cortex E-field (E_VC), mean primary visual cortex E-field (E_V1), targeting ratio (TR), specificity index (SI), and spatial focality (F75). Among five protocols, protocol 4 (O1-Cz)—Cz-return electrode montage—showed superior targeting ratio and specificity index than Fp-return electrode montage, while showing comparable visual cortex electric field intensity. Return electrode placement was identified as a deterministic factor for visual cortex stimulation selectivity. The O1→Cz montage provides the optimal balance between field intensity, selectivity, and focality, and is identified as optimal electrode montage over commonly used fronto-occipital configurations for visual cortex tDCS.
