Connectionists: World wide VVTNS series: Wednesday, March 20 at 11am (EDT), Merav Stern, Rockefeller University

[David Hansel]

Important:
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[image: VVTNS.png]
https://www.wwtns.online - on twitter: wwtns at TheoreticalWide

You are cordially invited to the lecture  given by

Merav Stern

Rockefeller University

on the topic of

*"*Conversions between space and time in network dynamics

by neural assemblies*"*

The lecture will be held on zoom on *March 20, 2024*, at *11:00 am EDT *

https://u-paris.zoom.us/j/87296214746?pwd=V3oyZ1JaQUxWVWp1TS9LS0ZiM0xiQT09
<https://streaklinks.com/A9c7PbX_v605iPoFlQDfpvyU/https%3A%2F%2Fu-paris.zoom.us%2Fj%2F87296214746%3Fpwd%3DV3oyZ1JaQUxWVWp1TS9LS0ZiM0xiQT09>


Id: 872 9621 4746

Passwd: 688274


*Abstract: *The connectivity structure of many biological systems,
including neural circuits, is highly non-uniform. Recent technologies allow
detailed mapping of these irregularities, but our understanding of their
effect on the overall circuit dynamics is still lacking. By developing
complex system analytical tools that perform reduction of the network, I
determine the impact of connectivity features on network dynamics. I will
demonstrate the use of these tools on neural assemblies (clusters), a
ubiquitous non-uniform structure in our brains. I will show how neural
assemblies of different sizes naturally generate multiple timescales of
activity spanning several orders of magnitude. I will demonstrate how the
analytical theory we develop for rate networks, supported by spiking
network simulations, reveals the dependency between neural timescales and
assembly sizes and how new recordings of spontaneous activity from a
million neurons support this analysis. I will also show how our model can
naturally explain the particular long-tailed timescale distribution
observed in the awake primate cortex. In olfactory cortex, neural
assemblies represent odor stimuli.  Previously, I showed how the diffuse
recurrent excitation among these assemblies allows the conversion of
time-encoded inputs from the bulb to spacial neural assembly
representations in olfactory cortex. Here, I will show how changes in the
dynamical properties of these assemblies alter both their timing response
and properties of the time-encoded inputs via feedback. This demonstrates
the role of neural assemblies in time-sensitive modulation needed for
cognitive tasks, such as attention. Our results offer a biologically
plausible mechanism of assemblies in network connectivity for explaining
multiple puzzling dynamical phenomena: The ability of neural circuits to
transform external simultaneous temporal fluctuations into spatial
representations and alter them; and the ability of neuronal circuits to
generate simultaneous temporal fluctuations across a large range of
timescales.

*About VVTNS : Created as the World Wide Neuroscience Seminar (WWTNS) in
November 2020 and renamed in homage to Carl van Vreeswijk in Memoriam
(April 20, 2022), its aim is to be a platform to exchange ideas among
theoreticians. Speakers have the occasion to talk about theoretical aspects
of their work which cannot be discussed in a setting where the majority of
the audience consists of experimentalists. The seminars, **held on
Wednesdays at 11 am ET,**  are 45-50 min long followed by a discussion. The
talks are recorded with authorization of the speaker and are available to
everybody on our YouTube channel.*
ᐧ
-- 
'Life is good ..' (Carl van Vreeswijk, 1962-2022)
---------------------------------------
David Hansel
Directeur de Recherche  au CNRS
Co-Group leader
Cerebral Dynamics Plasticity and Learning lab., CNRS
45 rue des Saints Peres 75270 Paris Cedex 06
Tel (Cell):   +33 607508403 - Fax (33).1.49.27.90.62

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