Performance of an MEG Adaptive-Beamformer Source Reconstruction Technique in the Presence of Additive Low-Rank Interference

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

Research output: Contribution to journalArticle


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.

Original languageEnglish (US)
Pages (from-to)90-99
Number of pages10
JournalIEEE Transactions on Biomedical Engineering
Issue number1
StatePublished - Jan 1 2004



  • Adaptive beamformer
  • Biomagnetism
  • Functional neuroimaging
  • MEG inverse problems
  • Magnetoencephalography
  • Neuromagnetic signal processing

ASJC Scopus subject areas

  • Biomedical Engineering

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