to the inverse problem (source localization methods) used in many applications in EEG and SEEG. The inverse solution requires repeated computation of the forward problem, i.e. the simulation of EEG and SEEG fields for a given dipolar source in the brain using a volume-conduction model of the head. As for DBS, the location of source is well defined. Therefore, in this thesis, we search for the best head model for the forward problem from real synchronous measurements of EEG and SEEG with DBS in several patients. So, the work of the thesis breaks up into different parts for which we need to accomplish the following tasks : - Creation of database : 3000 DBS measurements for 42 patients ; - Extraction of DBS signal from SEEG and EEG measurements using multidimensional analysis : 5 methods have been developed or adapted and validate first in a simulation study and, secondly, in a real SEEG application ; - Localization of SEEG electrodes in MR and CT images, including segmentation of brain matter. - SEEG forward modeling using infinite medium, spherical and realistic models based on MRI and CT of the patient ; - Comparison between different head models and validation with real in vivo DBS measurements. - Validation of realistic 5-compartment FEM head models by incorporating the conductivities of cerebrospinal fluid (CSF), gray and white matters.
