A simulation and experimental study on equivalent dipole layer imaging of brain electric sources

A simulation and experimental study has been conducted on equivalent dipole layer imaging (EDLI) of brain electric sources from EEG. Using the three-sphere inhomogeneous head model, the performance of the EDLI was rigorously evaluated for a variety of brain source configurations under different noise levels. The present simulation results demonstrate the excellent performance of the EDLI in mapping and imaging the underlying cortical sources with much enhanced spatial resolution, as compared to the scalp potentials. Human experiments were further conducted to examine the feasibility of EDLI. Pattern reversal visual evoked potentials (VEP) were recorded from 94 electrodes and the brain electric sources at P100 were estimated. The VEP experiments demonstrate that the present EDLI can eliminate the misleading far field in the scalp potential map, localize and map the underlying cortical sources induced by the visual stimuli.