Influence of personalized human head modeling and resolution on EEG source localization for rapid brain mapping

Objective.To evaluate the trade-offs among model resolution, anatomical fidelity, computational cost, and localization accuracy in electroencephalography (EEG) source imaging using personalized head models. Special emphasis was placed on segmentation-free modeling and sparse inverse analysis for rapid brain mapping.Approach. Forward problems were solved using a scalar-potential finite-difference method combined with orthogonal matching pursuit for inverse source localization. Tissue conductivity was directly estimated from magnetic resonance images using machine learning models, including CondNet and CondNet-TART, to generate personalized, continuous conductivity distributions without explicit segmentation. Localization accuracy and computational efficiency were compared across different model resolutions and against a finite-element method (FEM) using a five-tissue head model.Main results. Segmentation-free models achieved localization errors below 23 mm while maintaining stable accuracy even at coarser resolutions. Estimated current density distributions exhibited smooth transitions across tissue boundaries. Computational time was reduced by 87.9% compared with FEM at 2.0 mm resolution. Among segmentation-free models, CondNet-TART yielded the highest localization accuracy and stability.Significance.The proposed segmentation-free framework provides efficient and accurate EEG source localization with substantially reduced computational cost. These features support time-sensitive applications such as presurgical functional mapping and real-time neuroimaging.