Basics of Basics of Electro-EncephaloGraphy (EEG) and electrical source imaging

During this presentation, the basic principles acquisition and analysis of Electro-EncephaloGraphy (EEG) data will be reviewed. We will first present the origins of these signals measured using EEG that allows monitoring neuronal bioelectrical activity at a millisecond scale from few electrodes placed on the scalp.

After having reviewed the information of interest that could be extracted from EEG data when analyzing brain activity during task or at rest, the second part of the presentation will demonstrate that EEG studies consist indeed in imaging studies after source localization has been applied. Source localization is a difficult ill-posed inverse problem that consists in recovering, within the brain, the generators of the signals that were measured from the scalp electrodes.

The main advantages and common pitfalls of source localization procedures will be presented. The talk will conclude on discussion regarding how many EEG electrodes one should consider to do a proper EEG study and in a comparison of EEG versus Magneto-EncephaloGraphy (MEG) source localization accuracy.