Connectionists: Fwd: [seminar.wwtns] World wide VVTNS series (fifth season): Wednesday, February 12, 2025, at 11:00 am EST| Lea Duncker, Standford

[David Hansel]

[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 given by

Lea Duncker

Stanford


 on the topic of

Evaluating dynamical systems hypotheses for pattern generation in motor
cortex


The lecture will be held on zoom on Wednesday, February 12, 2025, at *11:00
am EST *
To receive the link: https://www.wwtns.online/register-page

*Abstract: * The rich repertoire of skilled mammalian behavior is the
product of neural circuits that generate robust and flexible patterns of
activity distributed across populations of neurons. Decades of associative
studies have linked many behaviors to specific patterns of population
activity, but association alone cannot reveal the dynamical mechanisms that
shape those patterns. Are local neural circuits high-dimensional dynamical
reservoirs able to generate arbitrary superpositions of patterns with
appropriate excitation? Or might circuit dynamics be shaped in response to
behavioral context so as to generate only the low-dimensional patterns
needed for the task at hand? Here, we address these questions within the
primate motor cortex by delivering optogenetic and electrical
microstimulation perturbations during reaching behavior. We develop a novel
analytic approach that relates measured activity to theoretically
tractable, dynamical models of excitatory and inhibitory neurons. Our
computational modeling framework allows us to quantitatively evaluate
different hypotheses about the dynamical mechanisms underlying pattern
generation against perturbation responses. Our results demonstrate that
motor cortical activity during reaching is shaped by a self-contained,
low-dimensional dynamical system. The subspace containing task-relevant
dynamics proves to be oriented so as to be robust to strong non-normal
amplification within cortical circuits. This task dynamics space exhibits a
privileged causal relationship with behavior, in that stimulation in motor
cortex perturbs reach kinematics only to the extent that it alters neural
states within this subspace. Our results resolve long-standing questions
about the dynamical structure of cortical activity associated with
movement, and illuminate the dynamical perturbation experiments needed to
understand how neural circuits throughout the brain generate complex
behavior.

*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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