Date : 01/02/2011

Laboratory
LNC, Laboratoire de Neurosciences Cognitives
INSERM U960, ENS
29 rue d'Ulm 75005 Paris
Director : Etienne Koechlin
website : www.lnc.ens.fr

Team
GNT, Group for Neural Theory
team leader : Boris Gutkin
website : www.gnt.ens.fr

PhD Supervisor
Boris Gutkin
email : This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
phone : +33 1 44 32 26 59

Subjects / Tools-Methodologies
1 : computational neuroscience/dynamical systems
2 : dynamical systems/statistical theory
3 : biomathematics/computer simulations

Summary of lab's interests

The Group for Neural Theory was founded in 2005 as part of the Départment d'Etudes Cognitives (DEC) at the Ecole Normale Supérieure (ENS) in Paris. Since January 2009, we are also affiliated with the INSERM Unité 960 (Laboratoire de Neurosciences Cognitives). Our main research goal is to understand the basis of information processing in the brain by identifying links between neural dynamics and neural function. To that end, we investigate a broad range of topics in computational neuroscience, including models of probabilistic inference, feature integration, and statistical learning in neuronal architectures; models of drug addiction; models of spiking and non-spiking recurrent networks; models of short-term memory and decision-making; spike-based learning algorithms; short-term synaptic plasticity; among others.

Summary of project

During development the cerebral cortex uses the activity patterns of its afferents to inform circuit construction. This activity is generated spontaneously in afferent structures (such as retinal or spinal chord) during early development, but in response to sensory stimuli during the later period. This developmental shift from ‘internal’ to ‘externally’ driven activity is accomplished not only through changes in peripheral sense organs, but also by changes in the cortical networks that transmit sensory information. In the visual system this shift occurs at eye opening in rodents, but at birth in human infants. Before birth, activity in cortex is characterized by a complex of characteristics that constitute a unique state, most prominently: (1) long duration silent periods and (2) response to sensory input with long-duration bursts consisting of rapid oscillations and large-amplitude slow waves. Such bursting is essential for the transmission of potentially weak spontaneous activity during early development, but is also detrimental for the sensory processing required of a functional system. The transition from this immature super-bursting mode to adult-like sensory processing occurs a rapid shift between states. This shift is experience independent and is tied to the integration of cortical circuits into attentional networks. Its timing however is sensory-system specific and timed to the beginnings of active sensory exploration within each modality. How such a rapid transition between cortical states can be caused by developing neuronal properties that develop along a more extended time-scale is an important question that is critical to our understanding of activity regulation during development and in disease states. The doctoral project will consist of developing a mechanistic models of the switch. We will work on the hypothesis that the fast switch is due to continuous developmental changes in cortical properties. Such a switch can be viewed as a functional bifurcation. The doctoral student will develop models of the switch conceptually based on principles of symmetry breaking and pattern formation. Such models have been successfully used to explain orientation preferences in primary visual neurons, formation of direction preference maps and visual halluciations. We will build on the mathematics of symmetry breaking to construct models of the sensory switch. We will explore how the changes in the structural properties of cortical sensory networks, in the cellular and synaptic properties, can lead to the all-or-none switch in its function and the on-going activity. The fellow will be supervised by Boris Gutkin (GNT, ENS) and will work in close collaboration with the team of R Khazipov at INMED (Marseille). Potential collaborations with P Bressloff (U Oxford) may be developed.