title: MEG forward problem formulation using equivalent surface current densities.
abstract: We present a formulation for the magnetoencephalography (MEG) forward problem with a layered head model. Traditionally the magnetic field is computed based on the electric potential on the interfaces between the layers. We propose to express the effect of the volumetric currents in terms of an equivalent surface current density on each interface, and obtain the magnetic field based on them. The boundary elements method is used to compute the equivalent current density and the magnetic field for a realistic head geometry. We present numerical results showing that the MEG forward problem is solved correctly with this formulation, and compare it with the performance of the traditional formulation. We conclude that the traditional formulation generally performs better, but still the new formulation is useful in certain situations.
authors.affiliation: Laboratorio de Electrónica Industrial, Control e Instrumentación, Departamento de Electrotecnia, Facultad de Ingeniería, Universidad Nacional de La Plata, Argentina. nellen@ieee.org
authors.forename: Nicolás
authors.initials: N
authors.lastname: von Ellenrieder
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Muravchik
authors.forename: Arye
authors.initials: A
authors.lastname: Nehorai
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004574:Electromagnetic Fields; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008959:Models, Neurological