Dipolar source localization from intracerebral SEEG recordings

This paper aims at exploring the feasibility of a brain source localization method from intracerebral stereo-electroencephalography (SEEG) measurements. The SEEG setup consists in multi-contact electrodes inserted in the brain volume, each containing about 10 collinear measuring contacts. In clinical context, these signals are usually observed using a bipolar montage (potential differences between neighbouring contacts of a SEEG electrode). The propagation of distant activity is thus suppressed, resulting in the observation of local activities around the contacts. We propose in this paper to take benefit of the propagation information by considering the original SEEG recordings (common reference montage), with the objective to localize sources possibly distant from the electrode contacts, and whose activities are propagating through the volume. Our method is based on an equivalent dipole model for the source and homogeneous infinite models for the propagation environment. This simple approach shows satisfactory localization performance under appropriate conditions, described in this paper. The proposed method is validated on real SEEG signals for the localisation of an intra-cortical electrical stimulation (ICS) generator.