title: Spatial filtering of MEG signals for user-specified spherical regions.
abstract: We introduce a spatial filtering method in the spherical harmonics domain for constraining magnetoencephalographic (MEG) multichannel measurements to any user-specified spherical region of interest (ROI) inside the head. The method relies on a linear transformation of the signal space separation inner coefficients that represent the MEG signal generated by sources located inside the head. The spatial filtering is achieved effectively by constructing a spherical harmonics basis vector that is dependent on the center of the targeted ROI and it does not require any discrete division of the headspace into grids like the traditional MEG spatial filtering approaches. The validation and the performance of the method are demonstrated through both simulated and actual bilateral auditory-evoked data experiments.
authors.affiliation: Institute for Medical Psychology and Clinical Neuroscience, Heinrich Heine University, Düsseldorf 40225, Germany. tolgaozkurt@gmail.com
authors.forename: Tolga Esat
authors.initials: TE
authors.lastname: Ozkurt
authors.forename: Mingui
authors.initials: M
authors.lastname: Sun
authors.forename: Wenyan
authors.initials: W
authors.lastname: Jia
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Sclabassi
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D006257:Head / Q000033:anatomy & histology; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D012815:Signal Processing, Computer-Assisted; D014732:Vibration