Dynamique de l'excitabilité neuronale: approches théorique et numérique

Jonathan Platkiewicz 1
1 APMN - Equipe Audition
LPP - Laboratoire psychologie de la perception
Abstract : Neurons generate electrical spikes in an all-or-none manner: a stereotypical action potential is produced and propagated whenever the stimulus amplitude is large enough, and not triggered otherwise. The minimal amplitude above which a spike is initiated is called the excitability threshold. Recent in vivo experiments have shown that this threshold can be highly variable. Moreover, it has been observed that the threshold can be adapted to the recent membrane activity history. These observations were of particular interest because they seemed to challenge fundamental hypotheses in the biophysics of excitability, and classical conceptions of synaptic integration. We raised then the following questions: How and to what extent do the different biophysical excitability mechanisms contribute to threshold variability? More specifically, what is the impact of sodium channel inactivation on spike threshold dynamics? We have tackled these questions by analyzing and simulating different mathematical models of neuronal excitability. First, we have observed that standard models can account for the significant threshold variability. This variability can be predicted from the dynamics of the biophysical excitability variables. Secondly, we have confirmed that sodium channel inactivation can account for the different threshold characteristics. Thus, our work confirms the relevance of threshold models for describing the dynamics of neuronal excitability.
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https://tel.archives-ouvertes.fr/tel-00612602
Contributor : Jonathan Platkiewicz <>
Submitted on : Saturday, November 26, 2011 - 4:46:50 PM
Last modification on : Thursday, April 11, 2019 - 4:02:23 PM
Long-term archiving on : Monday, February 27, 2012 - 2:20:10 AM

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  • HAL Id : tel-00612602, version 1

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Jonathan Platkiewicz. Dynamique de l'excitabilité neuronale: approches théorique et numérique. Neurosciences [q-bio.NC]. Université René Descartes - Paris V, 2010. Français. ⟨NNT : 2010PA05T0⟩. ⟨tel-00612602⟩

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