MEEG

The MEEG plugin for EEGLAB enables you to perform ICA analysis on simultaneously recorded MEG/EEG data. Each recovered component has a single activation time-series projecting to both EEG and MEG channels, yielding dual, orthogonal, topographies. This analysis has the potential for improving localization and revealing radial sources present in EEG, but not MEG, empirically demonstrating MEG's insensitivity to radially directed sources.

Figure: Examples of MEEG component maps, showing orthogonal topographies, and lack of MEG projection of radial brain sources. Numbers above each topo pair indicate %variance explained, [dipole fit residual variance; angle of EEG dipole from radial].

Figure: The ratio of explained variance in EEG vs MEG for each component. As dipole angle approaches radial (0°) relative MEG power decreases. Example IC topographies are shown for highly radial (left) and tangential (right) souces.

The plugin is described in the following slides from the most recent EEGLAB workshop: New Tools: MEEG Analysis (John Iversen)

A chapter describing it is published in the S. Supek and C. J. Aine (eds.), Magnetoencephalography, Springer, 2014 (pdf)

Please email John Iversen for more details, especially if you'd like to test the plugin or have MEEG data you would like to analyze.