Influence of the head model on EEG and MEG source connectivity analyses
Influence of the head model on EEG and MEG source connectivity analyses
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DOI：
10.1016/j.neuroimage.2015.01.043
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发表时间：
2015-04-15
期刊：
影响因子：
5.7
通讯作者：
Knoesche, Thomas R.
中科院分区：
文献类型：
--
作者：
Cho, Jae-Hyun;Vorwerk, Johannes;Knoesche, Thomas R.
利用脑电和脑磁图数据重构的源时间过程进行脑连通性分析的结果取决于许多算法的选择。虽然以往的研究已经探讨了源估计方法选择或连通性度量的影响，但对头部建模误差或简化的影响研究不够。在本仿真研究中，我们研究了头部模型的特定属性对重构的源时间过程以及对脑电图和脑磁图源连通性分析的影响。因此，我们构建了一个真实的头部模型，并应用有限元法求解脑电和脑磁图正演问题。我们考虑了白质和灰质的区别，致密骨和海绵状骨的区别，脑脊液（CSF）室的包含，以及还原为仅包括皮肤、颅骨和大脑的简单3层模型。采用波束形成方法重构源时程，利用虚相干性（ICoh）和广义部分定向相干性（GPDC）估计源的连通性。我们的研究结果表明，在脑电图和脑磁图中，忽略白质和灰质的区分或脑脊液会导致重构源时间过程和连通性分析的相当大的误差，而海绵状骨和致密骨的区分只有很小的相关性，只要使用足够的颅骨电导率值。在正解中显示出较大地形误差的同一区域，发现了较大的逆误差和连通性误差。此外，我们证明，与GPDC相反，非常保守的ICoh相对安全，不受头部模型不完美引起的串扰效应的影响。(C) 2015年作者。Elsevier Inc.出版。这是一篇基于CC BY-NC-ND许可（http://creativecommons.org/licenses/by-nc-nd/4.0/）的开放获取文章。
The results of brain connectivity analysis using reconstructed source time courses derived from EEG and MEG data depend on a number of algorithmic choices. While previous studies have investigated the influence of the choice of source estimation method or connectivity measure, the effects of the head modeling errors or simplifications have not been studied sufficiently.In the present simulation study, we investigated the influence of particular properties of the head model on the reconstructed source time courses as well as on source connectivity analysis in EEG and MEG. Therefore, we constructed a realistic head model and applied the finite element method to solve the EEG and MEG forward problems. We considered the distinction between white and gray matter, the distinction between compact and spongy bone, the inclusion of a cerebrospinal fluid (CSF) compartment, and the reduction to a simple 3-layer model comprising only the skin, skull, and brain. Source time courses were reconstructed using a beamforming approach and the source connectivity was estimated by the imaginary coherence (ICoh) and the generalized partial directed coherence (GPDC).Our results show that in both EEG and MEG, neglecting the white and gray matter distinction or the CSF causes considerable errors in reconstructed source time courses and connectivity analysis, while the distinction between spongy and compact bone is just of minor relevance, provided that an adequate skull conductivity value is used. Large inverse and connectivity errors are found in the same regions that show large topography errors in the forward solution. Moreover, we demonstrate that the very conservative ICoh is relatively safe from the crosstalk effects caused by imperfect head models, as opposed to the GPDC. (C) 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).