Physiological and electrical information about the brain can be obtained via a wide array of techniques such as the Electroencephalography (EEG), the Positron Emission Tomography (PET), Magnetic Resonance imaging (MRI) and Functional MRI (fMRI) which all have their trade-offs. One of the most popular acquisition techniques used both for research and for clinical application is the EEG which is an affordable and noninvasive technology that measures the electric potential on the scalp of the subject by means of a set of electrodes. The EEG is also used for EEG source imaging (ESI) which aims at computing the intracranial electrical activity from the electric potential measured on the surface of the head.