POST-DOCTORAL POSITION
Collaborative Project Inserm / Inria - POSTDOC 1

Topic. Neuro-glio-vascular coupling: models for the interpretation of  
EEG/MEG/IRMf data in epilepsy

Abstract. Epilepsy is a neurological disorder which affects 1% of the  
population worldwide. It is defined by the recurrence of seizures in  
relation with a dysfunction of one or several brain regions organized  
into « epileptogenic » networks. In a therapeutic perspective, the  
characterisation of these networks can be helped by neuroimaging  
techniques like EEG, MEG and functional MRI. However, the information  
conveyed by these different modalities remains difficult to unify and  
to interpret, due to our very partial understanding of i) the  
relationships between neurones and astrocytes (glia) which play a  
conjoint role in the generation of field potentials (reflected in  
electrophysiological observations as EEG and MEG) and ii) the links  
between neuronal activity and cerebral blood flow (also regulated by  
astrocytic activity) at the origin of the signal measured by fMRI.

The objective of this post-doc position is to participate in the  
elaboration of biophysical models aimed at describing the main  
mechanisms involved into the generation of electric and hemodynamic  
responses of neuronal populations. From a formal viewpoint, these  
models correspond to coupled nonlinear dynamical systems (ODE).  
Required competences (biology, physics, mathematics, engineering) and  
data (intra/extra-cellular activity, LFPs, MRI) for model elaboration  
and study are present in the consortium (Inserm & Inria teams). In  
particular, the applicant could start from already-existing models  
that can be extended and coupled. A mathematical analysis  
(bifurcations, aggregation of variables) as well as a parameter  
identification study is also planned. The elaboration of such models  
is essential in order to describe the potential role of glial cells in  
the properties of data acquired in healthy subjects and epileptic  
patients, not only in electrophysiology (EEG/MEG) but also in imaging  
(IRMf) as developed models should bridge between cellular processes  
and macroscopic non invasive data.

In practice. The offered position is part of a collaborative project  
between Inserm (Grenoble, Marseille Paris, Rennes) and Inria  
(Sophia-Antipolis). The candidate will be located in Rennes and  
meetings will be organized in Grenoble and Paris (frequency TBD).  
Salary : 1800 Euros net per month (founded by Inserm).

Skills.  Modeling (and/or) computational neurosciences, biophysics,  
differential systems, signal processing, object-oriented programming

Contacts :
Fabrice WENDLING, Laboratoire Traitement du Signal et de L'Image,   
INSERM U642 - UNIVERSITE DE RENNES 1, Campus de Beaulieu, 35042 Rennes  
Cedex - France -
Tel : (33) 2 23 23 56 05 ou (33) 2 23 23 62 20. Fax : (33) 2 23 23 69 17
Email : [log in to unmask],   
http://perso.univ-rennes1.fr/fabrice.wendling/

Olivier DAVID, Grenoble Institut des Neurosciences, INSERM U836 - CHU  
Grenoble, Bâtiment E.J. Safra, BP 170, 38042 Grenoble Cedex 9
Tel: +33 4 56 52 05 86, +33 4 56 52 05 99 (secr), Fax: +33 4 56 52 05 98
Email: [log in to unmask], http://neurosciences.ujf-grenoble.fr/



POST-DOCTORAL POSITION
Collaborative Project INRIA/ INSERM - POSTDOC 2

Topic: Investigation of the fluctuations of neuronal activity during  
epileptic discharges and comparison with the states of a neural mass  
model.
Framework
The project takes place within a collaboration between INRIA and  
INSERM on models for the interpretation of multimodal datasets (MEG,  
EEG, fMRI). The goal of this project is to build computational models  
for the generation of multimodal data, in order to (i) gain a better  
understanding of the impact of the different parameters of neuronal  
activity on simulated non-invasive measurements (ii) use  
neural-mass-type models in an inverse problem of source estimation  
from MEG/EEG/fMRI.

Project: a first step within this general framework is to identify the  
model parameters and the relevant model states. With this goal in  
view, it will be necessary to quantify the fine spatio-temporal  
characteristics of the neuronal activity and of the corresponding fMRI  
BOLD signal. This will permit in a second step to identify the states  
of the model that are compatible with the observations, and finally to  
explain the transitions between background activity and epileptic  
discharges.
We will concentrate on a particular type of neuronal activity:  
interictal epileptic discharges in cortical dysplasia. These  
activities can be well characterized by non-invasive (EEG, MEG)  
recordings. However, to start with measurements which are  
artefact-free and close to the sources, the candidate will first study  
intracerebral data (SEEG), and will broaden the investigation to  
simultaneous MEG-SEEG and simultaneous EEG-fMRI.

Skills: signal processing, computational neuroscience, applied mathematics
Practical aspects: the post-doc will take place mainly between the  
INSERM U751 laboratory (Marseille) and the Odyssée project-team at  
INRIA Sophia-Antipolis. Salary: see INRIA payroll.

Contacts :
Christian Bénar, Laboratoire épilepsie et cognition, INSERM U751,  
Marseille [log in to unmask]
Maureen Clerc, Equipe-projet Odyssée, INRIA Sophia-Antipolis,  
[log in to unmask]