Design and construction of a brain magnetic signal generation phantom for source reconstruction study

Magnetoencephalography (MEG) is a powerful tool in measuring magnetic fields associated with human brain activities, provided that a reliable inverse analysis method is available for mapping the recorded magnetic field patterns to active regions of neurons in the brain. The present study aims to develop a method of physically generate magnetic field patterns of which the MEG data can be used for developing a novel dipole localization technique. The mechanism of generating specific magnetic field patterns consists of coils attached to individual signal-generating circuits controlled by a central unit linked to a computer through a standard USB port. This study explored various coil designs that generated the simulated-brain magnetic dipoles. The use of triangular coils, as opposed to magnetic dipoles generated by helical coils, was also studied. The use of triangular coils was observed to have limitations in modelling true dipoles. The inverse analysis technique developed in association with this study showed high consistency in mapping the location and directionality of the source dipoles.