Connectionists: REMINDER: World wide VVTNS series (6th season): Neural Manifolds in Spinal Networks that Orchestrate Movement | Wednesday, March 25, 2026, at 11:00 am ET -Rune Berg, University of Copenhagen

[David Hansel]

WARNING: USA IS AT SUMMER TIME.
11am ET = 3pm GMT=4pm CET
[image: VVTNS.png]
https://www.wwtns.online
<https://streaklinks.com/A9c7PbbpKY7PxB6PaAJWGD3-/https%3A%2F%2Fwww.wwtns.online>
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on twitter: wwtns at TheoreticalWide

You are cordially invited to  the lecture

Rune Berg

University of Copenhagen


 on the topic of

Neural Manifolds in Spinal Networks that Orchestrate Movement
The lecture will be held on zoom on March 25 ,2026, at *11:00 am ET *

> To receive the link: https://www.wwtns.online/register-page
>

*Abstract: *How does a cat gracefully walk and suddenly freeze when
spotting a mouse? In this talk, we look at how networks in the spinal cord
generate movement. In particular, we address the fundamental yet poorly
understood question of motor control: How can rhythmic movements, such as
walking, be generated and stopped at any point in the cycle while posture
is preserved? Since conventional models of spinal motor function rely on
alternation between flexor and extensor modules, which are limited to just
two phases, this question exposes the essential shortcoming of the
conventional understanding: How can a system with only two phases generate
and stop walking in any phase? To address this question and better
understand the generation and stopping of motor activity, we use
Neuropixels probes in the rat spinal cord during voluntary, freely moving
locomotion. We utilize optogenetic activation of a brainstem nucleus to
induce stopping. During locomotion, neuronal manifold activity exhibits
robust rotational patterns that are topologically invariant with respect to
speed (Linden 2022). Furthermore, this trajectory converges on a stable
point-attractor precisely at the moment of arrest, and it persists until
the movement is resumed. Through computational modeling, we propose that
the walk-to-stop represents a bifurcation from a limit cycle to a fixed
point attractor. We also propose a structural network mechanism for its
physical implementation (Komi 2026). The structural mechanism entails a
longitudinal projectome with a skewed Mexican hat topology, i.e., primarily
local recurrent excitation and longer-range inhibition. Such a network can
generate motor patterns via traveling waves, with frequency and amplitude
controlled independently, and rhythm induced without requiring cellular
pacemaker mechanisms. Together, our experimental observations support a new
theory for the mechanism behind the generation of movement by networks in
the spinal cord.


*About VVTNS : Launched as the World Wide  Theoretical Neuroscience Seminar
(WWTNS) in November 2020 and renamed in homage to Carl van Vreeswijk in
Memoriam (April 20, 2022), 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.*


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