Congratulations to our new FdV doctor Tiffany LIEURY, who graduated on 28 Nov. 2011 at the CRI.

Title (french) : Transitoires calciques présynaptiques induits par dépolarisation membranaire: amélioration des méthodes dédiées à leur détection automatique et à leur analyse.

details below

Abstract :
Depolarisation-induced presynaptic \ca-transients: improved methods for their analysis and
their automated detection
On the real complexity of analyzing \ca-imaging data
In neurons transient and local elevations of the intracellular free calcium ions concentration influence the excitability and the synaptic efficacy. In small axonal compartements, the dynamics of
presynaptic calcium transients was shown to play a major role in the control of neurotransmitter release, and thus in the communication between neurons. Kinetics of presynaptic calcium transients
are usually investigated by estimating parameters of interest on recorded data using different models of calcium dynamics, while the distribution of the data is assumed to be Normal with a
constant variance. Unfortunately this assumption does not hold for data acquired with a CCD camera because of the photon noise, hence leading to unreliable parameter estimations. By adapting
an existing CCD camera noise model, we have developed a correct statistical framework to reliably estimate the parameters of interest of 2 models of calcium dynamics. Based on the correct
distribution of \ca-imaging data acquired with a CCD camera, we propose a statistical method for an automated detection of signals of interest and adjust its parameters for the specific detection of high
amplitude presynaptic calcium transients. Finally we adapt to calcium imaging data a novel method for denoising and clustering signals.

JURY
Pr Thibault Collin Université Paris Diderot
Dr Christophe Pouzat CNRS
Pr Peter Kloppenburg Université de Cologne
Dr Stéphane Dieudonné ENS
Dr Christophe Zimmer Institut Pasteur
Dr Yves Rozenholc Université Paris Descartes