Document sans-titre

Issues: The aim of this project is the study of the physiopathological processes of the epilepsies and the cerebral functions based on electroencephalography signals, recorded on the head surface (EEG) or inside the brain (StereoEEG). Of this context, two main axes can be released on the one hand the study of the physiopathological mechanisms which underlie the epileptic seizure, the identification of the related cortical networks and their relationship to the normal cognitive networks (in particular verbal and autobiographical memory) and on the other hand the identification of the neural networks relied in the physiological mnemic processes (encoding, storage, restitution). This principle consists in highlighting dynamic electrophysiological markers of these networks and analyzing modes of functional coupling between the distant cerebral areas within these networks.

Problematic: EEG signals can result from physiopathological epileptic mechanisms can be evoked by experimental and physiological cognitive paradigms for the mnemic processes or be generated by electric stimulations of the cerebral cortex. In this last case, stimulation activates the electrophysiological network and generates the corresponding clinical signs. The input-output relation “stimulus verbal/epilepsy/electric stimulation” is the goal of this work. How to find best input? By studying output EEG, can one define the anatomical contributions of the various structures? How these structures communicate?

The registration of IRMf type imagery data and High resolution EEG is a possible way of localization of the brain physiological phenomena, electric stimulation can contribute to the modeling of these phenomena when it causes foreseeable reactions indexed both on the EEG and on the clinical signs. If the access to the SEEG opened the way of the modeling of the epileptic networks, their structural and functional interpretation complex symptoms. A contrario of the epilepsy, the mnemic processes are sources of events very low energy however the initial moment can be perfectly defined on the temporal axis when they are ordered by verbal or auditive stimulation. The challenge is to conceive and/or adapt methods of EEG/SEEG processing. The space, temporal and frequential variations of multidimensional and nonstationary signals EEG/SEEG imply the development of complex methods of processing and analysis.

Originality: The neurology department of the CHU of Nancy has a consequent database of EEG and SEEG in the case of severe epilepsy. The SEEG gives access to electrophysiological information underlying structures with a space resolution of a few millimetres and temporal resolution about the millisecond. The functional electrophysiology of the memory remains a rather confidential subject. This work can be only the fruit of a close interaction between the clinical functional neurophysiology and the implementation of methodology of treatment of the signal. The specificity of the various members of this project constitutes the complementary of necessary competences to its success. This work is carried out in collaboration with two laboratories INSERM: the LTSI of Rennes and the laboratory of Neurophysiology of Marseille. The aspects approached are complementary to the work posted in these laboratories.