CURRENT DIPOLE MODEL FOR THE ELECTROENCEPHALOGRAM AND THE MAGNETOENCEPHALOGRAM, WITH APPLICATION TO DIAGNOSIS OF THE CENTRAL NERVOUS SYSTEM DISEASES.

Spatial relationships between brain electrical activities and magnetic fields of the head due to internal current sources are described. First, a method is presented for determining the potential distributions of abnormal brain activities over the surface of the head from current dipoles caused by brain lesions. Second, spatial distributions of magnetic fields perpendicular to the surface of the head due to the current dipoles are mapped. Third, the relationships between the electric potential fields and the magnetic fields are investigated, changing both location and orientation of the dipoles. The results indicate that the spatial patterns of the electric and magnetic fields are complementary, and the dipole orientation is determined by the simultaneous measurements of both the electroencephalogram and the magnetoencephalogram.