Generalized Head Models for MEG / EEG : BEM beyond Nested Volumes

Accurate geometrical models of the head are necessary for solving the forward and inverse problems of magnetoand electro-encephalography (MEG/EEG). Boundary element methods (BEM) require a geometrical model describing the interfaces between different tissue types. Classically, head models with a nested volume topology have been used. In this manuscript, we demonstrate how this constraint can be relaxed, allowing to model more realistic head topologies. We describe the symmetric BEM for this new model. The symmetric BEM formulation uses both potentials and currents on the interfaces as unknowns and is in general more accurate than the alternative double-layer formulation. PACS numbers: 41.20.Cv Submitted to: Physics in Medicine and Biology

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