Image de Raphael Nogueira

Wednesday, 5 pm CET, i.e, 11 am EST

 

Organized by David Hansel & Carl van Vreeswijk, CNRS,  France

 

About the Seminar

WWTNS is a weekly digital seminar on Zoom targeting the theoretical neuroscience community. 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  are 45 min long followed by a discussion and are held on Wednesdays at 5 pm in Western Europe, i.e, 11 am EST. The talks are recorded with authorization of the speaker and are available to everybody on our YouTube channel.

 

To participate in the seminar you need to fill out a registration form after which you will

receive an email telling you how to connect.

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Tatyana Sharpee

Salk Institute

March, 3, 2021

 Reading out responses of large neural populations with

minimal information loss

Classic studies show that in many species – from leech and cricket to primate – responses of neural populations can be quite successfully read out using a measure neural population activity termed the population vector. However, despite its successes, detailed analyses have shown that the standard population vector discards substantial amounts of information contained in the responses of a neural population, and so is unlikely to accurately describe how signal communication between parts of the nervous system. I will describe recent theoretical results showing how to modify the population vector expression in order to read out neural responses without information loss, ideally. These results make it possible to quantify the contribution of weakly tuned neurons to perception. I will also discuss numerical methods that can be used to minimize information loss when reading out responses of large neural populations.

 

Maoz Shamir

Ben Gurion University

March, 10, 2021

 STDP and the transfer of rhythmic signals in the brain

Rhythmic activity in the brain has been reported in relation to a wide range of cognitive processes. Changes in the rhythmic activity have been related to pathological states. These observations raise the question of the origin of these rhythms: can the mechanisms responsible for generation of these rhythms and that allow the propagation of the rhythmic signal be acquired via a process of learning? In my talk I will focus on spike timing dependent plasticity (STDP) and examine under what conditions this unsupervised learning rule can facilitate the propagation of rhythmic activity downstream in the central nervous system. Next, the I will apply the theory of STDP to the whisker system and demonstrate how STDP can shape the distribution of preferred phases of firing in a downstream population. Interestingly, in both these cases STDP dynamics does not relax to a fixed-point solution, rather the synaptic weights remain dynamic. Nevertheless, STDP allows for the system to retain its functionality in the face of continuous remodeling of the entire synaptic population.

Organizers

David Hansel

I am a theoretical neuroscientist at the National Center for Scientific Research in Paris, France and visiting professor at The Hebrew University in Jerusalem, Israel. I am mainly interested in the recurrent dynamics in the cortex and 

basal ganglia.

Carl van Vreeswijk

I am a theoretical neuroscientist working at the National Center for Scientific Research in Paris, France. My main interest is the dynamics of recurrent networks of neurons in the sensory system

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