Lee Won Hee, Liu Zhongming, Mueller Bryon A, Lim Kelvin, He Bin
Department of Biomedical Engineering, University of Minnesota, MN 55455, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:2923-5. doi: 10.1109/IEMBS.2009.5334468.
The goal of this study was to experimentally investigate the influence of the white matter (WM) anisotropy on the EEG source localization. We acquired both visual evoked potential (VEP) and functional MRI (fMRI) data from three human subjects presented with identical visual stimuli. A finite element method (FEM) head model with or without incorporating the WM anisotropy was built to solve the EEG forward problems, and single-dipole source localization was subsequently performed based on the N75 VEP component. The localized dipole positions were quantitatively compared with the locations of the fMRI activations within the primary visual cortex (V1). The results show that the distance between the localized N75 dipole position and the fMRI V1 activation center was slightly smaller when using an anisotropic model than when using an isotropic model. This experimental study suggests that compared to the conventional isotropic model, the anisotropic models incorporating realistic WM anisotropic conductivity distributions do not significantly improve the accuracy of the EEG dipole localization within V1.
本研究的目的是通过实验研究白质（WM）各向异性对脑电图源定位的影响。我们从三名接受相同视觉刺激的人类受试者身上获取了视觉诱发电位（VEP）和功能磁共振成像（fMRI）数据。构建了包含或不包含WM各向异性的有限元方法（FEM）头部模型来解决脑电图正向问题，随后基于N75 VEP成分进行单偶极子源定位。将定位的偶极子位置与初级视觉皮层（V1）内fMRI激活的位置进行定量比较。结果表明，使用各向异性模型时，定位的N75偶极子位置与fMRI V1激活中心之间的距离比使用各向同性模型时略小。这项实验研究表明，与传统的各向同性模型相比，纳入实际WM各向异性电导率分布的各向异性模型并不能显著提高V1内脑电图偶极子定位的准确性。
