Abstract
The authors have developed a three-dimensional (3-D) second-order gradiometer connected to three SQUIDs for vector measurement of MEG that can detect magnetic field components perpendicular and tangential to the scalp simultaneously. Each coil is orthogonally wound with Nb-Ti wire on a rectangular solid 3/spl times/3/spl times/6 cm. To assess discrimination and separation of multiple sources, the authors carried out both simulation study and 3-D vector measurement of MEG with mixed AEF (auditory evoked field) and SEF (somatosensory evoked field) overlapping in time. The magnetic field distribution perpendicular to the scalp was not helpful for estimating the location and number of sources, owing to the lack of a dipole pattern. But the magnetic field distribution tangential to the scalp can provide information about new constraint conditions by visual inspection. The authors estimated multiple sources of mixed AEF and SEF from the MEG data of the magnetic field tangential to the scalp and confirmed by comparison with MRI of a subject's head superimposed source locations.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
