Multi-scale Analysis of Physiological Brain Networks

Brain function is based on the communication between sets of neurons at different spatial and temporal scales. The dysfunction of these networks is thus at the origin of several brain pathologies, including epilepsy. The recent improvement in recording methods paves the way for better characterization of brain networks, with several spatial and temporal resolutions, depending on the techniques used.

Still, several key points remain outstanding. First, several mechanisms can underlie the interaction between brain regions, and it remains to determine the most relevant tools in practice to quantify them. Second, there are difficulties in extracting these networks from surface recordings. The best strategies for studying these interactions in a non-invasive way therefore remain to be defined.

It will be propose to answer these questions based on simultaneous surface (magneto-encephalography/ electroencephalography) and depth (intracerebral stereotactic EEG, SEEG) recordings, a technique it was developed by the team of Marseille, in patients undergoing preoperative epilepsy assessment.

The primary objective is to find, among all the mechanisms of interaction between brain regions, which are most relevant in describing physiological and pathological brain networks.

The secondary objective is to test whether the visible coupling information at depth can be found from surface data (EEG, MEG) only. To do this, it will be compare the surface results with the SEEG results.

The SEEG implantation is performed on purely clinical criteria for preoperative diagnosis. Magnetoencephalography and EEG are purely passive techniques that do not involve any additional risk. This project is a continuation of an existing project in which we have demonstrated the feasibility of simultaneous SEEG and MEG/EEG recordings.

Inclusion criteria

• Inclusion criteria for patients

• Patients for whom intracerebral electrode implantation is in progress as part of the pre-surgical evaluation of their drug-resistant partial epilepsy.
• Patient informed, expressing his non-opposition (or legal representative (s), affiliated to a social security scheme
• The medical examination is carried out as part of the medical follow-up of these patients
• Inclusion criteria for control subjects

• Informed subject, expressing his non-opposition or legal representative, affiliated to a social security scheme
• Exclusion Criteria:

Minors under 12 years

• Pregnant or lactating women,
• The adults under guardianship or under the protection of justice
• Non-beneficiaries of a social security scheme
• Persons deprived of their liberty by a judicial or administrative decision
• Absence of informed consent