Improved measurement surface for MEG using magnetic-dipole sources and a spherical-multipole expansion

[摘要] The multipole representation of Magnetoencephalography (MEG) signals is knownas a useful tool for distinguishing between magnetic fields arising from thebrain and external disturbances. In this contribution we extend this conceptand show that a closed double-layer surface with magnetometer probes isbetter suited to determine the corresponding multipole amplitudesα_lm than a conventional single-layer surface with gradiometersand magnetometer probes. For two different source configurations we show thatthe α_lm rapidly converge to the exact values. This proof ofconcept motivates to further optimize the geometry of the double-layersurface and the sensors' positions.

[学科分类] 电子、光学、磁材料