Zainea Ovidiu F, Kostopoulos George K, Ioannides Andreas A
Department of Physiology, Medical School, University of Patras, Patras, Greece.
Brain Topogr. 2005 Summer;17(4):219-36. doi: 10.1007/s10548-005-6031-3.
Median nerve electrical stimulation (MNES) produces early and strong averaged magnetoencephalography (MEG) or electroencephalography (EEG) signals, despite considerable single trial (ST) variability, demonstrated in separate MEG and EEG studies. Here, simultaneous MEG/EEG recordings are used to assess whether same or different aspects of ST variability are influencing EEG and MEG. Clustering techniques provided groupings for the ST timeseries for cortical responses to MNES derived from one modality. These groupings were applied to the corresponding ST timeseries derived from the other modality to quantify the similarity in variability captured by MEG and EEG signals. Estimates of early cortical activity elicited by MNES derived from MEG and EEG signals were very similar, provided ongoing mu rhythm was removed. Similarity between EEG and MEG estimates included both results based on average signals and measures of ST variability. Either MEG or EEG can provide a robust measure of the early cortical activity elicited by MNES as well as of its variability. Reliable indices of early cortical responses to MNES can be derived from either MEG or EEG data. These indices can be based on average signals, as is routinely done with clinical EEG, but it could also rely on hitherto little utilized measures of ST variability.
尽管在单独的脑磁图（MEG）和脑电图（EEG）研究中已证明，正中神经电刺激（MNES）会产生早期且强烈的平均MEG或EEG信号，但单次试验（ST）的变异性很大。在这里，同时进行MEG/EEG记录，以评估ST变异性的相同或不同方面是否正在影响EEG和MEG。聚类技术为源自一种模式的MNES皮质反应的ST时间序列提供了分组。这些分组应用于源自另一种模式的相应ST时间序列，以量化MEG和EEG信号捕获的变异性中的相似性。如果去除持续的μ节律，由MEG和EEG信号得出的MNES诱发的早期皮质活动估计非常相似。EEG和MEG估计之间的相似性包括基于平均信号的结果和ST变异性的测量。MEG或EEG均可提供对MNES诱发的早期皮质活动及其变异性的可靠测量。对MNES早期皮质反应的可靠指标可从MEG或EEG数据中得出。这些指标可以基于平均信号，就像临床EEG常规所做的那样，但也可以依赖于迄今很少使用的ST变异性测量。
