title: Surface-source modeling and estimation using biomagnetic measurements.
abstract: We propose a number of electric source models that are spatially distributed on an unknown surface for biomagnetism. These can be useful to model, e.g., patches of electrical activity on the cortex. We use a realistic head (or another organ) model and discuss the special case of a spherical head model with radial sensors resulting in more efficient computations of the estimates for magnetoencephalography. We derive forward solutions, maximum likelihood (ML) estimates, and Cramér-Rao bound (CRB) expressions for the unknown source parameters. A model selection method is applied to decide on the most appropriate model. We also present numerical examples to compare the performances and computational costs of the different models and illustrate when it is possible to distinguish between surface and focal sources or line sources. Finally, we apply our methods to real biomagnetic data of phantom human torso and demonstrate the applicability of them.
authors.affiliation: Department of Biomedical Engineering, University of California at Davis, 451 East Health Sciences Drive, Davis, CA 95616, USA. isyetik@ucdavis.edu
authors.forename: Imam Samil
authors.initials: IS
authors.lastname: Yetik
authors.forename: Arye
authors.initials: A
authors.lastname: Nehorai
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Muravchik
authors.forename: Jens
authors.initials: J
authors.lastname: Haueisen
authors.forename: Michael
authors.initials: M
authors.lastname: Eiselt
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D006801:Humans; D008280:Magnetics; D015225:Magnetoencephalography / Q000379:methods*; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology*