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@ens.fr) and Olivier Faugeras (Olivier.Faugeras@sophia.inria.fr). For further information please contact Romain Brette.

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