NEUROMAGNETIC FIELD COMPUTATION USING THE MULTIPLE MULTIPOLE METHOD

For the interpretation of human neuromagnetic data it is necessary to compute the magnetic field of a source (e.g. a dipole) in a volume con ductor (e.g. a homogeneous conducting sphere or a homogeneous head mod el). The Multiple Multipole (MMP) method, which is a semianalytical fi eld calculation method, is applied to neuromagnetic field calculation for the first time. The unique feature of the MMP method is that multi pole expansions are used for the description of the electromagnetic fi eld. First a validation of the MMP method is done with the help of a s pherical model and an analytical solution. Then the MMP method is appl ied to a realistically shaped one compartment head model. The results are compared to results obtained with the Boundary Element Method (BEM ). The results suggest that it is possible to solve the neuromagnetic forward problem faster with the help of the MMP method than with the c onventional numerical field calculation methods for realistic shaped v olume conductor models. Further investigations are necessary to tackle the inverse problem of biomagnetism with the MMP method.