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Electro-magneto-encephalography for a three-shell model: distributed current in arbitrary, spherical and ellipsoidal
1Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, UK. t.fokas@damtp.cam.ac.uk
Journal of the Royal Society, Interface
|September 2, 2008
Summary
Electroencephalography (EEG) and magnetoencephalography (MEG) together provide partial information on brain currents. Complete reconstruction requires additional assumptions, like harmonicity, for accurate neuronal current mapping.
Area of Science:
- Biophysics
- Neuroscience
- Medical Imaging
Background:
- Determining neuronal current distribution is crucial for understanding brain activity.
- The three-shell model is a common simplification for head conductivity.
- Existing methods face limitations in fully reconstructing complex current patterns.
Purpose of the Study:
- To analyze the information content of EEG and MEG for reconstructing distributed neuronal currents.
- To investigate the combined capabilities of EEG and MEG in a three-shell brain model.
- To identify limitations and potential solutions for complete current determination.
Main Methods:
- Mathematical analysis of current distribution within a three-shell model.
- Investigating the information provided by electroencephalography (EEG).
- Investigating the information provided by magnetoencephalography (MEG).
Main Results:
- EEG provides information on one component of the neuronal current.
- MEG provides information on a combination of two current components.
- Simultaneous EEG-MEG use yields information on two of the three required functions.
- Spherical/ellipsoidal geometries allow determination of angular parts and constraints on radial parts.
Conclusions:
- Combined EEG and MEG offer significant but incomplete information for neuronal current reconstruction.
- Complete determination necessitates additional assumptions, such as harmonicity.
- Future research may focus on incorporating such assumptions for enhanced brain current mapping.
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