在存在加性低秩干扰情况下的脑磁图自适应波束形成器源重建技术的性能

Performance of an MEG adaptive-beamformer source reconstruction technique in the presence of additive low-rank interference.

作者信息

Sekihara Kensuke, Nagarajan Srikantan S, Poeppel David, Marantz Alec

机构信息

Department of Electronic Systems and Engineering, Tokyo Metropolitan Institute of Technology, Asahigaoka 6-6, Hino, Tokyo 191-0065, Japan.

出版信息

IEEE Trans Biomed Eng. 2004 Jan;51(1):90-9. doi: 10.1109/TBME.2003.820329.

DOI:10.1109/TBME.2003.820329

PMID:14723498

Abstract

The influence of external interference on neuromagnetic source reconstruction by adaptive beamformer techniques was investigated. In our analysis, we assume that the interference has the following two properties: First, it is additive and uncorrelated with brain activity. Second, its temporal behavior can be characterized by a few distinct activities, and as a result, the spatio-temporal matrix of the interference has a few distinctly large singular values. Namely, the interference can be modeled as a low-rank signal. Under these assumptions, our analysis shows that the adaptive beamformer techniques are insensitive to interference when its spatial singular vectors are so different from a lead field vector of a brain source that the generalized cosine between these two vectors is much smaller than unity. Four types of numerical examples verifying this conclusion are presented.

摘要

研究了外部干扰对自适应波束形成技术进行神经磁源重建的影响。在我们的分析中，我们假设干扰具有以下两个特性：第一，它是加性的且与脑活动不相关。第二，其时间行为可以由少数几种不同的活动来表征，因此，干扰的时空矩阵具有少数几个明显较大的奇异值。也就是说，干扰可以建模为低秩信号。在这些假设下，我们的分析表明，当干扰的空间奇异向量与脑源的导联场向量差异很大，以至于这两个向量之间的广义余弦远小于1时，自适应波束形成技术对干扰不敏感。给出了验证这一结论的四类数值示例。