Publications associées à Période réfractaire (physiologie)

Design and modelling of a tubular dielectric elastomer actuator with constrained radial displacement as a cardiac assist device

Yves Perriard, Yoan René Cyrille Civet, Armando Matthieu Walter, Jonathan André Jean-Marie Chavanne

In this paper, we propose an improvement of a dielectric elastomer actuator (DEA) based augmented aorta. The actuator is a multi-layered tubular DEA subject to the internal pressure of the blood. When activated in synchronisation with the heart, the DEA su ...

IOP PUBLISHING LTD2021

A computational biophysical model of thalamic and reticular nucleus microcircuitry: from neurons to emergent network dynamics

Elisabetta Iavarone

The thalamus, once believed to be a simple relay station between the body periphery and the neocortex, has started to be recognized as a key player in higher-order functions, such as attention. It participates in the transition between brain states, such a ...

EPFL2020

Deep learning-based reduced order models in cardiac electrophysiology

Alfio Quarteroni, Andrea Manzoni, Luca Dede'

Predicting the electrical behavior of the heart, from the cellular scale to the tissue level, relies on the numerical approximation of coupled nonlinear dynamical systems. These systems describe the cardiac action potential, that is the polarization/depola ...

2020

Mitochondrial cristae modeled as an out-of-equilibrium membrane driven by a proton field

Anne-Florence Raphaëlle Bitbol

As the places where most of the fuel of the cell, namely, ATP, is synthesized, mitochondria are crucial organelles in eukaryotic cells. The shape of the invaginations of the mitochondria inner membrane, known as a crista, has been identified as a signature ...

2020

Low-dimensional firing-rate dynamics for populations of renewal-type spiking neurons

Tilo Schwalger

The macroscopic dynamics of large populations of neurons can be mathematically analyzed using low-dimensional firing-rate or neural-mass models. However, these models fail to capture spike synchronization effects and nonstationary responses of the populati ...

AMER PHYSICAL SOC2020

On the stability and dynamics of stochastic spiking neuron models: Nonlinear Hawkes process and point process GLMs

Joao Emanuel Felipe Gerhard, Moritz Deger

Point process generalized linear models (PP-GLMs) provide an important statistical framework for modeling spiking activity in single-neurons and neuronal networks. Stochastic stability is essential when sampling from these models, as done in computational ...

Public Library of Science2017

Multi-timescale Modeling of Activity-Dependent Metabolic Coupling in the Neuron-Glia-Vasculature Ensemble

Pierre Magistretti, Igor Allaman, Renaud Jolivet, Jay Coggan

Glucose is the main energy substrate in the adult brain under normal conditions. Accumulating evidence, however, indicates that lactate produced in astrocytes (a type of glial cell) can also fuel neuronal activity. The quantitative aspects of this so-calle ...

2015

Finite element and finite volume-element simulation of pseudo-ECGs and cardiac alternans

Alfio Quarteroni, Ricardo Esteban Ruiz Baier

In this paper, we are interested in the spatio-temporal dynamics of the transmembrane potential in paced isotropic and anisotropic cardiac tissues. In particular, we observe a specific precursor of cardiac arrhythmias that is the presence of alternans in t ...

Wiley-Blackwell2015

An efficient initialization mechanism of neurons for Winner Takes All Neural Network implemented in the CMOS technology

Pierre-André Farine, Rafal Tomasz Dlugosz

The paper presents a new initialization mechanism based on a Convex Combination Method (CCM) for Kohonen self-organizing Neural Networks (NNs) realized in the CMOS technology. A proper selection of initial values of the neuron weights exhibits a strong imp ...

Elsevier Science Inc2015

Kinetics of Atrial Repolarization Alternans in a Free-Behaving Ovine Model

Jean-Marc Vesin, Florian Jousset, Etienne Pruvot

Kinetics of Atrial Repolarization Alternans. Introduction: Repolarization alternans (Re-ALT), a beat-to-beat alternation in action potential repolarization, promotes dispersion of repolarization, wavebreaks, and reentry. Recently, Re-ALT has been shown to ...

Wiley-Blackwell2012

Parameter extraction and classification of three cortical neuron types reveals two distinct adaptation mechanisms

Wulfram Gerstner, Carl Petersen, Richard Naud, Skander Mensi, Christian Antonio Pozzorini, Michael Avermann

Mensi S, Naud R, Pozzorini C, Avermann M, Petersen CCH, Gerstner W. Parameter extraction and classification of three cortical neuron types reveals two distinct adaptation mechanisms. J Neurophysiol 107: 1756-1775, 2012. First published December 7, 2011; do ...

American Physiological Society2012

Gate-controlled linear magnetoresistance in thin Bi2Se3 sheets

Klaus Kern, Marko Burghard, Pascal Gehring

We explore the emergence of linear magnetoresistance in thin Bi2Se3 sheets upon tuning the carrier density using a back gate. With increasingly negative gate voltage, a pronounced magnetoresistance of similar to 100% is observed, while the associated B-fie ...

AIP American Institute of Physics2012

Characterization of Atrial Repolarization Alternans and Activation Time Kinetics based on Intracardiac Electrograms

Florian Jousset

Interdisciplinary collaboration between physicians and engineers is now widespread in fundamental and clinical studies, due to the increasing complexity of the physiological problems tackled, and the development of novel measurement devices and data analys ...

EPFL2011

Synaptic Mechanisms Underlying Sparse Coding of Active Touch

Carl Petersen, Sylvain Crochet, Yves Emile Alfred Kremer, James Poulet

Sensory information is actively gathered by animals, but the synaptic mechanisms driving neuronal circuit function during active sensory processing are poorly understood. Here, we investigated the synaptically driven membrane potential dynamics during acti ...

2011

Active strain and activation models in cardiac electromechanics

Alfio Quarteroni, Ricardo Esteban Ruiz Baier, Simone Rossi

We present a model for mechanical activation of the cardiac tissue depending on the evolution of the transmembrane electrical potential and certain gating/ionic variables that are available in most of electrophysiological descriptions of the cardiac membra ...

2011

Mechanisms of Propagation of Intercellular Calcium Waves in Arterial Smooth Muscle Cells

Jean-Jacques Meister, Jean-Louis Bény, Dominique Seppey, Michèle Koenigsberger

In rat mesenteric arteries, smooth muscle cells exhibit intercellular calcium waves in response to local phenylephrine stimulation. These waves have a velocity of similar to 20 cells/s and a range of similar to 80 cells. We analyze these waves in a theoret ...

Elsevier2010

Complexity and performance in simple neuron models

Wulfram Gerstner, Richard Naud, Skander Mensi

The ability of simple mathematical models to predict the activity of single neurons is important for computational neuroscience. In neurons, stimulated by a time-dependent current or conductance, we want to predict precisely the timing of spikes and the su ...

2010

Membrane potential dynamics of GABAergic neurons in the barrel cortex of behaving mice

Carl Petersen, Michael Avermann, Ferenc Mátyás

Computations in cortical circuits are mediated by synaptic interactions between excitatory and inhibitory neurons, and yet we know little about their activity in awake animals. Here, through single and dual whole-cell recordings combined with two-photon mi ...

Elsevier2010

The effect of tissue geometry on the activation recovery interval of atrial myocytes

Vincent Jacquemet

The propagation of electric activity inside a realistically-shaped, thick-walled model of the atria was studied. The membrane kinetics was based on the formulations of Courtemanche, Ramirez and Nattel. In spite of the assumed uniformity of all kinetics par ...

2009

TRACE simulation of sodium boiling in pin bundle experiments under loss-of-flow conditions

Rakesh Chawla, Aurélia Chenu, Konstantin Mikityuk

In the framework of PSI's FAST code system, the thermal-hydraulic code TRACE is being extended for representation of sodium two-phase flow. As the currently available version (v.5) is limited to the simulation of only single-phase sodium flow, its applicab ...

Elsevier Science B.V.2009