A novel integrated MEG and EEG analysis method for dipolar sources
A novel integrated MEG and EEG analysis method for dipolar sources
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DOI：
10.1016/j.neuroimage.2007.06.002
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发表时间：
2007-09-01
期刊：
影响因子：
5.7
通讯作者：
Halgren, Eric
中科院分区：
文献类型：
--
作者：
Huang, Ming-Xiong;Song, Tao;Halgren, Eric
脑磁图 (MEG) 能够准确定位神经元电流并获得源的切向分量，这在很大程度上是由于 MEG 对头部组织的电导率分布不敏感。然而，MEG 无法可靠地检测神经元电流的径向分量。相比之下，脑电图（EEG）的定位精度不如MEG，但EEG可以检测源的切向和径向分量。在本研究中，我们研究了一种新方法中的电导率依赖性，该方法结合了 MEG 和 EEG，不仅可以准确获得源的位置和切向分量，还可以准确获得源的径向分量。在这种方法中，仅从 MEG 中获得源位置和切向分量，并通过最佳拟合 EEG 信号来估计 EEG 模型的最佳电导率值，同时精确匹配 EEG 和 MEG 中源的切向分量。然后，使用先前估计的最佳电导率值从 EEG 获得径向分量。测试这种集成方法的计算机模拟显示了两个主要发现。首先，电导率值有组织良好的最佳组合，可以准确拟合合并的 MEG 和 EEG 数据。其次，除了位置和切向分量之外，还可以高精度地获得径向分量，而无需知道磁头的精确电导率分布。然后，我们证明了这种新方法在对正中神经电刺激引起的人体感觉反应的 20 毫秒成分的分析中表现可靠。 (c) 2007 Elsevier Inc. 保留所有权利。
The ability of magnetoencephalography (MEG) to accurately localize neuronal currents and obtain tangential components of the source is largely due to MEG's insensitivity to the conductivity profile of the head tissues. However, MEG cannot reliably detect the radial component of the neuronal current. In contrast, the localization accuracy of electroencephalography (EEG) is not as good as MEG, but EEG can detect both the tangential and radial components of the source. In the present study, we investigated the conductivity dependence in a new approach that combines MEG and EEG to accurately obtain, not only the location and tangential components, but also the radial component of the source. In this approach, the source location and tangential components are obtained from MEG alone, and optimal conductivity values of the EEG model are estimated by best-fitting EEG signal, while precisely matching the tangential components of the source in EEG and MEG. Then, the radial components are obtained from EEG using the previously estimated optimal conductivity values. Computer simulations testing this integrated approach demonstrated two main findings. First, there are well-organized optimal combinations of the conductivity values that provide an accurate fit to the combined MEG and EEG data. Second, the radial component, in addition to the location and tangential components, can be obtained with high accuracy without needing to know the precise conductivity profile of the head. We then demonstrated that this new approach performed reliably in an analysis of the 20-ms component from human somatosensory responses elicited by electric median-nerve stimulation. (c) 2007 Elsevier Inc. All rights reserved.