Effects of forward model errors on EEG source localization.
Effects of forward model errors on EEG source localization.
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DOI：
10.1007/s10548-012-0274-6
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发表时间：
2013-07
期刊：
影响因子：
2.7
通讯作者：
Makeig, Scott
中科院分区：
文献类型：
--
作者：
Acar, Zeynep Akalin;Makeig, Scott
关键词：
使用NFT （www.sccn.ucsd.edu/wiki/NFT）从磁共振（MR）头部图像中生成四层边界元法（BEM）四名参与者的头部电正向模型，用于模拟脑空间三维网格中单电流偶极子产生的256个记录电极位置的脑电图（EEG）头皮电位。这些偶极子的位置，然后估计使用梯度下降在五个模板头模型适合电极的位置。这些是：基于蒙特利尔神经学研究所（MNI）模板头部图像的球形模型，三层和四层BEM头部模型，这些BEM模型弯曲到记录的电极位置。使用电极位置弯曲的四层BEM模型获得的定位误差最小（中位数为4.1-6.2 mm），大多数基底脑位置的定位误差最大（~20 mm）。当我们将模板模型头皮投影中假设的脑-颅骨电导率从模拟值（25:1）提高到早期研究中使用的更高值（80:1）时，估计的偶极子位置向外移动（中位数为12.4 mm）。我们还研究了共同登记电极位置、减少电极计数以及在单个头部模型中添加第五个各向同性白质层的误差的影响。结果表明，当个体受试者的MR头部图像无法用于构建受试者特定的头部模型时，准确的EEG源定位应该采用四层或五层BEM模板头部模型，该模型包含准确的颅骨电导率估计，并扭曲到64个或更多精确的三维测量和共同注册电极位置。
Subject-specific four-layer boundary element method (BEM) electrical forward head models for four participants, generated from magnetic resonance (MR) head images using NFT (www.sccn.ucsd.edu/wiki/NFT), were used to simulate electroencephalographic (EEG) scalp potentials at 256 recorded electrode positions produced by single current dipoles of a 3-D grid in brain space. Locations of these dipoles were then estimated using gradient descent within five template head models fit to the electrode positions. These were: a spherical model, three-layer and four-layer BEM head models based on the Montreal Neurological Institute (MNI) template head image, and these BEM models warped to the recorded electrode positions. Smallest localization errors (4.1–6.2 mm, medians) were obtained using the electrode-position warped four-layer BEM models, with largest localization errors (~20 mm) for most basal brain locations. When we increased the brain-to-skull conductivity ratio assumed in the template model scalp projections from the simulated value (25:1) to a higher value (80:1) used in earlier studies, the estimated dipole locations moved outwards (12.4 mm, median). We also investigated the effects of errors in co-registering the electrode positions, of reducing electrode counts, and of adding a fifth, isotropic white matter layer to one individual head model. Results show that when individual subject MR head images are not available to construct subject-specific head models, accurate EEG source localization should employ a four- or five-layer BEM template head model incorporating an accurate skull conductivity estimate and warped to 64 or more accurately 3-D measured and co-registered electrode positions.
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影响因子：
3.2
作者：
Ataseven, Y.;Akalin-Acar, Z.;Gencer, N. G.
通讯作者：
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影响因子：
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作者：
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通讯作者：
Cuffin, BN
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作者：
Delorme A;Palmer J;Onton J;Oostenveld R;Makeig S
通讯作者：
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作者：
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通讯作者：
Pernier, J