Influence of anisotropic conductivity on the EEG forward and inverse solution

Abstract

To get more realistic conductivity head models to perform source localization in EEG experiments, we included anisotropy information measured using DTI. Employing this anisotropic model we performed EEG forward simulations for 25.000 dipoles in the cortical area and compared the solution with forward solutions using an isotropic model by means of RDM and MAG. We found regions which are highly affected by anisotropy mainly in the sulci of the medial part of each hemisphere but also in the main sluci of the temporal lobe. Additionally we used the forward solution which was calculated using the anisotropic model and performed source localization employing a fully isotropic model. It has resulted that the topology of the localization error corresponds well with the relative difference measure (RDM). We conclude that inclusion of anisotropy information into volume conductor models will improve EEG source localization.