Three-dimensional Cortical Dipole Imaging of Brain Electrical Activity Considering Spherical and Median Planes

Equivalent cortical dipole layer imaging is proposed for high-resolution electroencephalogram (EEG) visualization. Equivalent dipole layer distribution parallel to the brain surface has been used in previous head models. In the present study, the additional dipole distribution on the median plane is introduced to identify the three-dimensional (3D) position and orientation of dipole sources. The parametric Wiener filter (PWF) using statistical signal and noise information was applied to solve an inverse problem of cortical dipole imaging. Simulations were performed in an inhomogeneous, concentric, three-sphere volume conductor head model under various signal conditions. Cortical dipole imaging provided localized brain electrical activity with better spatial resolution compared to the scalp potential map. These simulation results suggested that the depth and orientation of individual dipole sources could be observed by mapping on both spherical and median planes. We applied the proposed imaging technique to human experimental data of the visual evoked potential (VEP) and obtained reasonable results that coincide with physiological knowledge. (C) 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.