[The biophysical foundations of the localisation of encephalogram generators in the brain. The application of a distribution-type model to the localisation of epileptic foci].

INTRODUCTION: The brain electrical activity measured as the EEG signal is a powerful tool for the understanding of normal and pathological brain function. The EEG presents a high temporal resolution but a low spatial resolution. The latter can be improved solving the so-called inverse problem, if some a priori physiological and anatomical information is included. DEVELOPMENT: The present review presents the biophysical bases that allows brain source localization in realistic head models, as well as the two basic source models used: dipolar models and distributed source models. Finally, an example of practical application for the localization of epileptic focus using the distributed solution EPIFOCUS will be presented.