Frequency-spatial beamformer for MEG source localization

Elizabeth A. Thompson, Jing Xiang, Yingying Wang

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

This article introduces a unique and powerful new method for spatial localization of neuronal sources that exploit the high temporal resolution of magnetoencephalography (MEG) data to locate the originating sources within the brain. A traditional frequency beamforming algorithm was adapted from its conventional application to yield information on the spatial location of simulated neuronal signals. The concept is similar to that used in signal source localization in magnetic resonance imaging (MRI) in which spatial location is determined by the frequency of oscillation of the MR signal. Whereas a traditional frequency beamformer uses the time course values of all sensors in the dataset to assign a power value for each possible frequency in the signal, it provides no information on the spatial location of those frequencies. Our approach assigns a power value to each location in the three-dimensional head volume. To compute this power value, the time courses of a subset of sensors closest to that location in space are used rather than all the time courses in the dataset. Our novel technique incorporates actual MEG sensor locations of the closest sensors at each location in space. The approach is relatively simple to implement, yields good spatial resolution, and accurately spatially locates a simulated source in low signal-to-noise environments. In this work, its performance is compared to that of the synthetic aperture magnetometry (SAM) beamformer and shown to exhibit improved spatial resolution.

Original languageEnglish (US)
Pages (from-to)263-273
Number of pages11
JournalBiomedical Signal Processing and Control
Volume18
DOIs
StatePublished - Apr 2015

Keywords

  • Data driven
  • MEG source localization
  • Model-free
  • Spatial location
  • Statistical signal processing

ASJC Scopus subject areas

  • Signal Processing
  • Health Informatics

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