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arXiv 1203.3533cs.LGstat.ML
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MEG和EEG的声源分离和高阶因果分析

Source Separation and Higher-Order Causal Analysis of MEG and EEG

Max Planck Institute for Biological Cybernetics(马克斯·普朗克生物控制论研究所);University of Helsinki(赫尔辛基大学);HIIT(赫尔辛基信息技术研究所)

Kun Zhang, Aapo Hyvarinen

摘要:

源信号的分离和连通性分析一直是脑电分析中的一个重要课题。为了以自动的方式解决这个问题,我们提出了一个两层模型,其中的源是有条件地彼此不相关,但不是独立的;依赖性是由因果关系在其随时间变化的方差(信封)。该模型分两步确定。首先,我们提出了一种新的声源分离技术,考虑到自相关(这可能是时变的)和时变方差的来源。然后利用一种特殊的多变量广义自回归条件异方差模型发现包络中的因果关系。由此产生的因果图给出了分离的源之间的有效连接;在我们对MEG数据的实验结果中,具有相似功能的源被分组在一起,组之间存在负面影响,并且组通过一些有趣的源连接。

英文摘要:

Separation of the sources and analysis of their connectivity have been an important topic in EEG/MEG analysis. To solve this problem in an automatic manner, we propose a two-layer model, in which the sources are conditionally uncorrelated from each other, but not independent; the dependence is caused by the causality in their time-varying variances (envelopes). The model is identified in two steps. We first propose a new source separation technique which takes into account the autocorrelations (which may be time-varying) and time-varying variances of the sources. The causality in the envelopes is then discovered by exploiting a special kind of multivariate GARCH (generalized autoregressive conditional heteroscedasticity) model. The resulting causal diagram gives the effective connectivity between the separated sources; in our experimental results on MEG data, sources with similar functions are grouped together, with negative influences between groups, and the groups are connected via some interesting sources.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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