CONDUCTIVITY RATIOS OF THE SCALP-SKULL-BRAIN HEAD MODEL IN ESTIMATINGEQUIVALENT DIPOLE SOURCES IN HUMAN BRAIN

The dipole tracing (DT) method estimates the position and vector dipol e moment of an equivalent current dipole by minimizing the mean square d error of the dipole potentials at the surface electrode positions. I n the scalp-skull-brain/DT (SSB/DT) method, which we have developed, t he head model consists of three compartments of uniform conductors cor responding to the scalp, skull and brain. The accuracy of the calculat ions are mainly dependent on the ratios of the conductivities of the t hree compartments. The best result was obtained with the conductivity ratios of 1:1/80:1 for the scalp, skull and brain compartments, respec tively.