Model evaluation using electroencephalography and magnetoencephalography.

The source of both the measured visual evoked potentials and the measured visual evoked magnetic fields was estimated by means of an inverse procedure. The model used consisted of a single current dipole positioned in a volume conductor consisting of four concentric spheres. Comparison of the results showed that the estimations did not always match. In order to reveal a possible cause of this mismatch a realistically shaped multicompartment model of the head was constructed. From forward simulations it followed that the influence of the realistic shape was apparent, especially when the dipole was positioned deep within the brains.