From EEG source localization to source imaging.

A new functional imaging technique, "FOCUS", has been developed to transform the traditional scalp EEG into an image of source activities. The image is based on multiple spatio-temporal dipole models and consists of gross spatial patterns and source waveforms reflecting the estimated activities of the different brain regions. The application of the 'FOCUS' technique to the EEG in temporal lobe epilepsy revealed the presence of different activities at the basal and lateral aspects of the temporal lobe. The source waveforms showed propagation patterns consistent with subdural recordings which were not recognizable in the scalp EEG.