Abstract
Previously, single-dipole and two-dipole models were proposed to show how MEG can locate of brain activity. However, these models some drawbacks. In this paper, a spreading-source model is proposed to explain the phaseshift change in MEG waveforms depending on the recording position on the surface of the head. The proposed source model is consists of multiple spreading dipoles that have time-varying dipole moments. Two kinds of source area are assumed; one is flat, the other is curved. These source models are used to simulate, the spatio-temporal patterns of MEGs. Effects of spreading dipoles on spatiotemporal magnetic fields are investigated. The computer shows that the waveforms and amplitude of magnetic fields are significantly affected by the spread of the source and the propagation velocity of the excitation.
