MEG/EEG source modeling for localization and imaging of brain activity

For clarity purposes, we will not attempt to formalize in a general, overly technical way, the classes of approaches to MEG/EEG source estimation. We will rather adopt a pragmatic standpoint, observing that two main chapels have developed quite separately: the localization and the imaging approaches respectively (Salmelin & Baillet, 2009). Our purpose here is to mark methodological landmarks and stress on differences, similarities, and their respective assets.

(1) Source localization vs. source imaging

Two approaches for two different perspectives on imaging brain activity.

(2) Dipole fitting: the localization approach

Computational approaches to source localization attempt to mimic the talent of electrophysiologists, with a more quantitative benefit though.

(3) Scanning techniques: Spatial filters, beamformers and signal classifiers

The inherent difficulties to source localization with multiple generators and noisy data have led signal processors to develop alternative approaches, most notably in the glorious field of radar and sonar in the 1970’s.

(4) Distributed source imaging

MEG/EEG source images represent estimations of the global neural current intensity maps, distributed within the entire brain volume or constrained at the cortical surface.

(5) Appraisal of MEG/EEG source models

Modeling implies dealing with uncertainty. MEG/EEG source estimation has uncertainty everywhere. It is therefore reasonable to question how sensitive are the models to possible sources of errors and bias. This concerns the appraisal of the source model, which general methodology has been adapted to MEG/EEG rather recently and is now achieving significant maturity.

Froedtert & The Medical College of Wisconsin MEG Contact Information

Research investigators and clinical physicians are encouraged to contact us for further information on how to access our MEG Program and services.

  • Zhimin Li, PhD: Technical Manager
  • Jean Roccapalumba, CTRS, MBA: Program Manager

Mailing Address:

MEG Program
Department of Neurology
Medical College of Wisconsin
9200 W. Wisconsin Ave.
Milwaukee, WI 53226

MEG Program Site Map

If you are a physician and would like to inquire about or order a MEG study for your patients, please visit Froedtert Hospital MEG web pages for basic information about the procedure and/or contact Linda Allen, RN BSN, our Epilepsy Program Coordinator at (414) 805-3641 to refer your patient to our Program.

If you are a patient who is about to undergo an MEG procedure, please also visit Froedtert Hospital MEG web pages for useful information regarding the MEG routine.

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Page Updated 02/16/2015