Mideksa K G, Hellriegel H, Hoogenboom N, Krause H, Schnitzler A, Deuschl G, Raethjen J, Heute U, Muthuraman M
Department of Neurology, Christian Albrechts university, Kiel 24105, Germany.
Annu Int Conf IEEE Eng Med Biol Soc. 2012;2012:4903-6. doi: 10.1109/EMBC.2012.6347093.
The sources of somatosensory evoked potentials (SEPs) and fields (SEFs), which is a standard paradigm, is investigated using multichannel EEG and MEG simultaneous recordings. The hypothesis that SEP & SEF sources are generated in the posterior bank of the central sulcus is tested, and analyses are compared based on EEG only, MEG only, bandpass filtered MEG, and both combined. To locate the sources, the forward problem is first solved by using the boundary-element method for realistic head models and by using a locally-fitted-sphere approach for averaged head models consisting of a set of connected volumes, typically representing the skull, scalp, and brain. The location of each dipole is then estimated using fixed MUSIC and current-density-reconstruction (CDR) algorithms. For both analyses, the results demonstrate that the band-pass filtered MEG can localize the sources accurately at the desired region as compared to only EEG and unfiltered MEG. For CDR analysis, it looks like MEG affects EEG during the combined analyses. The MUSIC algorithm gives better results than CDR, and when comparing the two head models, the averaged and the realistic head models showed the same result.
采用多通道脑电图(EEG)和脑磁图(MEG)同步记录的方法,对体感诱发电位(SEPs)和体感诱发电场(SEFs)的来源进行了研究,这是一种标准范式。对SEP和SEF来源产生于中央沟后缘的假设进行了检验,并基于仅EEG、仅MEG、带通滤波后的MEG以及两者结合的方式进行了分析比较。为了定位来源,首先通过使用边界元法求解真实头部模型的正向问题,并通过使用局部拟合球体方法求解由一组连接体积组成的平均头部模型的正向问题,这些连接体积通常代表颅骨、头皮和大脑。然后使用固定多重信号分类(MUSIC)算法和电流密度重建(CDR)算法估计每个偶极子的位置。对于这两种分析,结果表明,与仅EEG和未滤波的MEG相比,带通滤波后的MEG能够在所需区域准确地定位来源。对于CDR分析,在联合分析中MEG似乎会影响EEG。MUSIC算法比CDR算法给出的结果更好,并且在比较两种头部模型时,平均头部模型和真实头部模型显示出相同的结果。