[Comp-neuro] Postdoc position in applied maths and computational neuroscience at Ecole Normale Superieure, Paris and/or at INRIA Sophia-Antipolis (near Nice).

[Romain Brette]

Postdoc position in applied mathematics and computational neuroscience 
at ENS Paris and/or at INRIA Sophia-Antipolis (near Nice).

Mathematical techniques for extracting synaptic activity from 
intracellular measurements in neurons.

The objective of this project is to develop, analyze and implement 
mathematical methods for extracting information about the synaptic 
conductances from neurophysiological recordings. To achieve this 
objective we propose to address the following three questions.
1) Measuring conductances in central neurons in vivo is essential to 
understand the response selectivity of those neurons. Response 
selectivity can arise from particular timings of excitation and 
inhibition, which can be amplified by intrinsic conductances. In 
intracellular experiments, one can measure the membrane potential V(t), 
but the conductances are hidden variables. We are interested in 
extracting the excitatory synaptic conductance ge(t) and the inhibitory 
conductance gi(t), which are related to V(t) through a differential 
equation. Because two variables are to be deduced from a single 
quantity, all previous methods are based on multiple trials, which 
necessarily mean that information about the variability unlocked to the 
stimulus is lost. We have started to develop a method for single-trial 
measurements, which uses a controlled noisy current injected in the 
neuron and a minimization procedure.
2) Another aspect of the project is the recording technique itself. 
Currently, our recordings use a novel technique called Active Electrode 
Compensation, which uses an electrode model and a computer program 
running in real time to control the recording electrode. There are 
several aspects of this technique which would need improvements and 
extensions.
3) Finally, we are also interested in extracting spike-triggered 
averages from intracellular recordings.

We are collaborating on this project with Alain Destexhe and Yves 
Frégnac at the UNIC lab (CNRS Gif-sur-Yvette), where all experiments 
(both in vitro and in vivo) will be performed. The postdoctoral fellow 
will test his algorithms on experimental data but is not expected to 
participate actively in the experiments. Details of the project are 
available there:
http://www.di.ens.fr/~brette/HRCORTEX/

We are looking for a postdoctoral fellow with expertise in applied maths 
or physics, and experience in programming. The research work will be 
related to the following domains: control theory, signal processing, 
dynamical systems, probabilities, optimization. Knowledge of 
neurophysiological models is a plus but is not required. A clear 
interest for interdisciplinary work is an obvious requirement.

The candidate will work for 2 years in the Odyssee Lab at the Computer 
Science Department of Ecole Normale Supérieure in Paris (45, rue d’Ulm, 
very central, in the heart of the Quartier Latin) and/or at INRIA 
Sophia-Antipolis, near Nice on the French Riviera. The position is fully 
funded by an ANR Neuroscience project.

Candidates should send a CV and the address of two referees to Romain 
Brette (Romain.Brette at ens.fr) and Olivier Faugeras 
(Olivier.Faugeras at sophia.inria.fr). For further information please 
contact Romain Brette.