抄録
In order to evaluate the conductor models, i. e. outer sphere (best fitting the cranium surface), cranium (surface itself) and inner sphere (best fitting the inner cranial surface) models, used in the neuromagnetic source localization, we measured magnetic fields using a cranium phantom filled with the saline. Current dipole sources in the phantom were localized with these three models. The three dimensional positions of the sources which were calculated with the cranium and inner sphere models showed good agreement with the actual source locations. Especially, cranium model is useful because of the easiness to obtain the data of the cranium surface. Using the cranium model, neuromagnetic sources evoked by monosyllable speech sounds (/ba/, /pa/, /ma/) were localized on the MRI tomograms and were compared with anatomical structure. On the horizontal plane of the MRI tomograms all the sources of different speech sounds were located in the transverse gyri of Heschl that is the primary auditory area. On the coronal plane they were located near the lower area of the Sylvian fissure, at which the transverse gyri of Heschl is located.
