title: Fourth order approaches for localization of brain current sources.
abstract: Two high resolution methods solving inverse problems potentially ill-posed, named 4-MUSIC and 4-RapMUSIC, are proposed. They allow for localization of brain current sources with unconstrained orientations from surface electro-or magneto-encephalographic data using spherical or realistic head geometries. The 4-MUSIC and 4-RapMUSIC methods are based on i) the separability of the data transfer matrix as a function of location and orientation parameters and ii) the fourth order (FO) virtual array theory. In addition, 4-RapMUSIC uses the deflation concept extended to FO statistics accounting for the presence of potentially but not totally coherent sources. Computer results display the superiority of the 4-RapMUSIC approach in different situations (two closed sources, additive Gaussian noise with unknown spatial covariance, ...) especially over classical algorithms.
authors.affiliation: INSERM UMR 642, Lab. Traitement du Signal et de 1'Image, Faculty of Elec.Engineering, Rennes 1 Univ., France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Albera
authors.forename: Anne
authors.initials: A
authors.lastname: Ferréol
authors.forename: Delphine
authors.initials: D
authors.lastname: Cosandier-Rimélé
authors.forename: Isabelle
authors.initials: I
authors.lastname: Merlet
authors.forename: Fabrice
authors.initials: F
authors.lastname: Wendling
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D001931:Brain Mapping; D003198:Computer Simulation; D004566:Electrodes; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D006257:Head; D006801:Humans; D015225:Magnetoencephalography / Q000295:instrumentation / Q000379:methods; D008959:Models, Neurological; D015233:Models, Statistical; D016011:Normal Distribution; D012815:Signal Processing, Computer-Assisted; D012984:Software