Interdisciplinary Thematic Institute (IRMIA++) - Alex Hutt

DATE :Thursday, January 18 at 9am, in the IRMA conference room

The talk will be given by Axel Hutt (ICube).

TITLE: Additive noise tunes the stability of high-dimensional systems

Abstract: Experimental brain activity is known to show oscillations in specific frequency bands, which reflects neural information processing. For instance, strong oscillations at about 2Hz reflect tiredness and sleepiness, strong 40Hz oscillations indicate alertness. Changes of power in frequency bands indicate changes in information processing. For instance, it has been observed that strong activity about 10Hz and 2Hz emerge in electroencephalographic activity (EEG) when a subject loses consciousness in general anaesthesia. Numerical simulations of stochastic neural models have shown that such a change can be reproduced by changing the variance of external additive Gaussian uncorrelated noise. At a first glance, this is surprising since additive is not supposed to affect a system’s oscillatory activity or stability. The presentation shows first how additive noise can affect a nonlinear system’s stability by applying stochastic center manifold analysis in non-delayed low-dimensional systems and delayed systems. Then, an extension to stochastic randomly connected network models shows that the observed effect also emerges. Applying random matrix theory together with mean-field theory demonstrates how additive noise tunes the stability and oscillatory activity in such systems. In sum, the mathematical studies provide an explanation why the brain’s oscillatory activity changes with changing experimental conditions.

About the speaker: Axel Hutt has studied physics at the University of Stuttgart supervised by Prof. Hermann Haken and worked on his PhD at the Max Planck Institute for Cognitive Neuroscience, for which he has received a  Schloessmann Fellowship Award of the Max Planck Society in the year 2000. After positions at the Weierstrass Institute for Applied Analysis and Stochastics in Berlin, the Humboldt University Berlin and the University of Ottawa/Canada, he started working at INRIA Nancy Grand Est in 2007 and became Directeur de Recherche at INRIA in 2015. In 2010, Axel received an ERC Starting Grant. After a sabbatical stay at the German Weather Service for 4 years, from 2019 on he is working in the INRIA-team MIMESIS / iCube-team MLMS in Strasbourg on stochastic nonlinear dynamics of brain models in the context mental disorders. 

Next seminar: 15/02/2024, Nalini Anantharaman (IRMA)