Identifying true brain interaction from EEG data using the imaginary part of coherency
Identifying true brain interaction from EEG data using the imaginary part of coherency
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DOI：
10.1016/j.clinph.2004.04.029
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发表时间：
2004-10-01
影响因子：
4.7
通讯作者：
Hallett, M
中科院分区：
文献类型：
--
作者：
Nolte, G;Bai, O;Hallett, M
目的：在解释脑电/脑磁图数据方面的主要障碍是，由于体积传导，一个单一的大脑源的活动可以在许多通道中观察到的事实。在这里，我们提出了一种方法，这是不敏感的虚假连接所产生的体积conduction.Methods：我们表明，非相互作用的源（复杂）的一致性必然是真实的，因此，虚部的一致性提供了一个很好的候选人来研究大脑的相互作用。虽然通常的幅度和相位的相干性包含相同的信息的真实的部和虚部，我们认为，笛卡尔表示是更上级的研究大脑的相互作用。结果：我们发现：（a）从运动开始前5 s左右，左右运动区在20 Hz左右有一个相对较弱的相互作用，其中对侧领先同侧;（B）运动后2-4 s左右，在20 Hz左右有一个相对较强的相互作用。结论：这是可能的，以可靠地检测从EEG data.Significance运动过程中的大脑互动：该方法允许明确的检测从节律EEG/MEG数据的大脑互动。(C)2004年国际临床神经生理学联合会。由Elsevier爱尔兰有限公司出版。保留所有权利。
Objective: The main obstacle in interpreting EEG/MEG data in terms of brain connectivity is the fact that because of volume conduction, the activity of a single brain source can be observed in many channels. Here, we present an approach which is insensitive to false connectivity arising from volume conduction.Methods: We show that the (complex) coherency of non-interacting sources is necessarily real and, hence, the imaginary part of coherency provides an excellent candidate to study brain interactions. Although the usual magnitude and phase of coherency contain the same information as the real and imaginary parts, we argue that the Cartesian representation is far superior for studying brain interactions. The method is demonstrated for EEG measurements of voluntary finger movement.Results: We found: (a) from 5 s before to movement onset a relatively weak interaction around 20 Hz between left and right motor areas where the contralateral side leads the ipsilateral side; and (b) approximately 2-4 s after movement, a stronger interaction also at 20 Hz in the opposite direction.Conclusions: It is possible to reliably detect brain interaction during movement from EEG data.Significance: The method allows unambiguous detection of brain interaction from rhythmic EEG/MEG data. (C) 2004 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.