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Alexander van Meegen

@avm.bsky.social
365 followers 483 following 14 posts

Theory of Neural Networks (how the heck do they work?) Assistant Professor @RWTH Previous: Postdoc @EPFL, Swartz Fellow @Harvard Lab: avmlab.physik.rwth-aachen.de Personal: alexvanmeegen.github.io Background art: www.bettina-hachmann.de

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Reposted by Alexander van Meegen
Louis Pezon @lpezon.bsky.social · 28/09/2026
How can RNNs re-use the same dynamics across different tasks to implement compositional computation? What are the consequences for network connectivity & activity? If you're interested, come and find out at the Bernstein Conference, poster session III-#48!
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Louis Pezon @lpezon.bsky.social · 30/06/2026
Both brains and RNNs can re-use components of computation across similar tasks or contexts. But what exactly are those “shared components”? How can they be used to solve several tasks? We address these questions in a new preprint with @avm.bsky.social! Link: www.biorxiv.org/content/10.6...
biorxiv.org
Interpretable compositional computation with recurrent neural networks
Flexible cognition utilizes reusable components to enable rapid adaptation of behavior to different contexts or tasks. Analysis of artificial neural networks trained on multiple tasks suggested that t...
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Alexander van Meegen @avm.bsky.social · 30/06/2026
Interested in multitasking RNNs from a theory perspective? Check out this preprint with the amazing @lpezon.bsky.social. TLDR: A low-rank / latent space approach to @lndriscoll.bsky.social & @sussillodavid.bsky.social style shared components. And a story starring solution space degeneracy.
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Jacob Zavatone-Veth @jzv.bsky.social · 23/06/2026
Tremendously excited to announce that I will be joining @rockefeller.edu as an Assistant Professor and Head of Lab starting in January 2027! My group will be broadly focused on theoretical neuroscience, and mathematical problems in neural computation in the large.
Rockefeller campus image from https://commons.wikimedia.org/wiki/File:Rockefeller_University_Campus_aerial_2.jpg, licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license.
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Flavio Martinelli @flavioh.bsky.social · 10/06/2026
NEW PAPER. Why do larger networks train better? "Because they contain more candidate *sub*networks that can learn the task" → lottery tickets This popular explanation uses an appealing but misleading metaphor🧵 We propose an intuitive alternative grounded in theory: escape dimensions
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Trish Greenhalgh @trishgreenhalgh.bsky.social · 23/05/2026
Every summer I repost this article on how to spot drowning. Please read it and pass on. In the last few years I’ve had SIX messages from people who saved a kid’s life after clicking on the link from my feed. slate.com/technology/2...
slate.com
Drowning Doesn’t Look Like Drowning
Drowning is not the violent, splashing call for help that most people expect.
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Valentin Schmutz @bio-emergent.bsky.social · 08/05/2026
Unbelievably honoured to read Tatiana Engel's (@engeltatiana.bsky.social) wonderfully written Preview on our work "Linking neural manifolds to circtuit structure in recurrent networks" (with @lpezon.bsky.social & @gerstnerlab.bsky.social) in this issue of Neuron www.cell.com/neuron/fullt... 🙏
cell.com
Finding clues to circuit structure in population dynamics and single-neuron selectivity
In this issue of Neuron, Pezon et al. introduce neural circuit models with flexible connectivity structure that can generate low-dimensional population dynamics with different distributions of single-...
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Friedemann Zenke @fzenke.bsky.social · 06/05/2026
1/7 New paper accepted as ICML spotlight arxiv.org/abs/2605.03517! We unify self-supervised learning (SSL) algorithms (e.g., contrastive, VICReg, stopgrad) via latent distribution matching (LDM), which matches an induced latent distribution to an explicit latent model.
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David G. Clark @david-g-clark.bsky.social · 28/04/2026
New preprint: "Linear equivalence of nonlinear recurrent neural networks." For large nonlinear (potentially chaotic) RNNs with random connectivity, the full N×N covariance matrix takes the same form as that of a ~linear~ network with the same couplings, driven by independent noise.
arxiv.org
Linear equivalence of nonlinear recurrent neural networks
Large nonlinear recurrent neural networks with random couplings generate high-dimensional, potentially chaotic activity whose structure is of interest in neuroscience, machine learning, ecology, and o...
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Dimitra Maoutsa @dimma.bsky.social · 15/03/2026
I am looking for a theory/computational POSTDOC position in EU or east coast US. I am interested in how learning and plasticity shape population dynamics & representational geometries & how these changes are reflected in behavior. If you are at #COSYNE2026 & interested, hit me up in Whova, not here
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Rainer Engelken @rainerengelken.bsky.social · 14/03/2026
Belated update: I joined UIUC ECE as an Assistant Professor. Our lab works at the intersection of theoretical neuroscience, machine learning, and dynamical systems, with a focus on learning and spiking networks. I had to miss #COSYNE2026 for visa reasons. 1/2
Poincare section of chaotic spiking network. Colors indicate local Lyapunov exponents.
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Louis Pezon @lpezon.bsky.social · 13/03/2026
Presenting a poster tomorrow at Cosyne 26: [3-033] Compositional computation via shared latent dynamics in low-rank RNNs. With @avm.bsky.social, we explore how RNNs can re-use the same dynamics across different tasks, and what it implies for their connectivity and neural activity.
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Alexander van Meegen @avm.bsky.social · 12/03/2026
Travelling to COSYNE seems to be the perfect opportunity to announce that I started my own lab at RWTH Aachen University earlier this year, funded by NRW's Ministry of Culture and Science through its Return Program. If you are at COSYNE and want to chat please reach out!
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Jacob Zavatone-Veth @jzv.bsky.social · 12/03/2026
If you're at #cosyne2026 in Lisbon, come check out Juan Carlos Fernández del Castillo's poster 1-007 tonight, based on our paper on efficient coding in olfaction (www.biorxiv.org/content/10.1...)!
biorxiv.org
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Louis Pezon @lpezon.bsky.social · 06/03/2026
Excited to share our new paper to be published in Neuron! With Valentin Schmutz @bio-emergent.bsky.social and Wulfram Gerstner @gerstnerlab.bsky.social, we explore how circuit structure in RNNs shapes network computation and single-neuron responses. www.sciencedirect.com/science/arti...
sciencedirect.com
Linking neural manifolds to circuit structure in recurrent networks
Dimensionality reduction methods are widely used in neuroscience to investigate two complementary aspects of neural activity: the distribution of sing…
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Neuron @cp-neuron.bsky.social · 06/03/2026
dlvr.it
Linking neural manifolds to circuit structure in recurrent networks
Neural population activity can be described either by low-dimensional dynamics on neural manifolds or by single-neuron selectivities. Using a theoretical approach, Pezon et al. relate these two statistical descriptions to circuit structure in recurrent networks. Their results reveal both degeneracies and specific constraints in how circuit structure shapes neural activity.
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David G. Clark @david-g-clark.bsky.social · 10/01/2026
Excited to be giving the van Vreeswijk Theoretical Neuroscience Seminar this Wednesday, Jan 14, where I'll talk about "Computation Through Neuronal-Synaptic Dynamics"! www.wwtns.online
wwtns.online
Home | Neuroscience | World Wide Theoretical Neuroscience 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.
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Guillaume Bellec @bellecguill.bsky.social · 18/12/2025
Our paper on data constrained RNN that generalize to optogenetic perturbations now citable on eLife: doi.org/10.7554/eLif...
doi.org
Biologically informed cortical models predict optogenetic perturbations
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Owen Marschall @omarschall.bsky.social · 15/12/2025
1/X Excited to present this preprint on multi-tasking, with @david-g-clark.bsky.social and Ashok Litwin-Kumar! Timely too, as “low-D manifold” has been trending again. (If you read thru the end, we escape Flatland and return to the glorious high-D world we deserve.) www.biorxiv.org/content/10.6...
biorxiv.org
A theory of multi-task computation and task selection
Neural activity during the performance of a stereotyped behavioral task is often described as low-dimensional, occupying only a limited region in the space of all firing-rate patterns. This region has...
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Flavio Martinelli @flavioh.bsky.social · 04/12/2025
🧵Excited to present our latest work at #Neurips25! Together with @avm.bsky.social, we discover 𝐜𝐡𝐚𝐧𝐧𝐞𝐥𝐬 𝐭𝐨 𝐢𝐧𝐟𝐢𝐧𝐢𝐭𝐲: regions in neural networks loss landscapes where parameters diverge to infinity (in regression settings!) We find that MLPs in these channels can take derivatives and compute GLUs 🤯
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Richard Gao @rdgao.bsky.social · 03/12/2025
Finally got the job ad—looking for 2 PhD students to start spring next year: www.gao-unit.com/join-us/ If comp neuro, ML, and AI4Neuro is your thing, or you just nerd out over brain recordings, apply! I'm at neurips. DM me here / on the conference app or email if you want to meet 🏖️🌮
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Athena Akrami @athenaakrami.bsky.social · 17/11/2025
paper🚨 When we learn a category, do we learn the structure of the world, or just where to draw the line? In a cross-species study, we show that humans, rats & mice adapt optimally to changing sensory statistics, yet rely on fundamentally different learning algorithms. www.biorxiv.org/content/10.1...
biorxiv.org
Different learning algorithms achieve shared optimal outcomes in humans, rats, and mice
Animals must exploit environmental regularities to make adaptive decisions, yet the learning algorithms that enabels this flexibility remain unclear. A central question across neuroscience, cognitive science, and machine learning, is whether learning relies on generative or discriminative strategies. Generative learners build internal models the sensory world itself, capturing its statistical structure; discriminative learners map stimuli directly onto choices, ignoring input statistics. These strategies rely on fundamentally different internal representations and entail distinct computational trade-offs: generative learning supports flexible generalisation and transfer, whereas discriminative learning is efficient but task-specific. We compared humans, rats, and mice performing the same auditory categorisation task, where category boundaries and rewards were fixed but sensory statistics varied. All species adapted their behaviour near-optimally, consistent with a normative observer constrained by sensory and decision noise. Yet their underlying algorithms diverged: humans predominantly relied on generative representations, mice on discriminative boundary-tracking, and rats spanned both regimes. Crucially, end-point performance concealed these differences, only learning trajectories and trial-to-trial updates revealed the divergence. These results show that similar near-optimal behaviour can mask fundamentally different internal representations, establishing a comparative framework for uncovering the hidden strategies that support statistical learning. ### Competing Interest Statement The authors have declared no competing interest. Wellcome Trust, https://ror.org/029chgv08, 219880/Z/19/Z, 225438/Z/22/Z, 219627/Z/19/Z Gatsby Charitable Foundation, GAT3755 UK Research and Innovation, https://ror.org/001aqnf71, EP/Z000599/1
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Nature Neuroscience @natneuro.nature.com · 10/11/2025
Connectome datasets alone are generally not sufficient to predict neural activity. However, pairing connectivity information with neural recordings can produce accurate predictions of activity in unrecorded neurons www.nature.com/articles/s41...
nature.com
Prediction of neural activity in connectome-constrained recurrent networks - Nature Neuroscience
The authors show that connectome datasets alone are generally not sufficient to predict neural activity. However, pairing connectivity information with neural recordings can produce accurate predictio...
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Alexander van Meegen @avm.bsky.social · 05/11/2025
This was a lot of fun! From my side, it started with a technical Q: what's the relation between two-side cavity and path integrals? Turns out it's a fluctuation correction - and amazingly, this also enable the "O(N) rank" theory by @david-g-clark.bsky.social and @omarschall.bsky.social. 🤯
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Paul Masset @paulmasset.bsky.social · 04/11/2025
First paper from the lab! We propose a model that separates estimation of odor concentration and presence and map it on olfactory bulb circuits Led by @chenjiang01.bsky.social and @mattyizhenghe.bsky.social joint work with @jzv.bsky.social and with @neurovenki.bsky.social @cpehlevan.bsky.social
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Blake Bordelon @frostedblakess.bsky.social · 23/10/2025
Applying to do a postdoc or PhD in theoretical ML or neuroscience this year? Consider joining my group (starting next Fall) at UT Austin! POD Postdoc: oden.utexas.edu/programs-and... CSEM PhD: oden.utexas.edu/academics/pr...
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Tatiana Engel @engeltatiana.bsky.social · 12/10/2025
A study led by Cina Aghamohammadi is now out in ‪@natcomms.nature.com‬! We developed a mathematical framework for partitioning spiking variability, which revealed that spiking irregularity is nearly invariant for each neuron and decreases along the cortical hierarchy. www.nature.com/articles/s41...
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Valentin Schmutz @bio-emergent.bsky.social · 19/09/2025
🎉 "High-dimensional neuronal activity from low-dimensional latent dynamics: a solvable model" will be presented as an oral at #NeurIPS2025 🎉 Feeling very grateful that reviewers and chairs appreciated concise mathematical explanations, in this age of big models. www.biorxiv.org/content/10.1... 1/2
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GerstnerLab @gerstnerlab.bsky.social · 30/09/2025
Lab members are at the Bernstein conference @bernsteinneuro.bsky.social with 9 posters! Here’s the list: TUESDAY 16:30 – 18:00 P1 62 “Measuring and controlling solution degeneracy across task-trained recurrent neural networks” by @flavioh.bsky.social
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Roxana Zeraati @roxana-zeraati.bsky.social · 03/09/2025
Check out our new preprint where we analyzed the dynamics of over ten thousand neurons across 223 brain areas and found a surprising universal principle that describes the organization of intrinsic timescales across the entire mouse brain, including subcortical structures! #neuroskyence
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Jacob Zavatone-Veth @jzv.bsky.social · 04/09/2025
Since I'm back on BlueSky - with @frostedblakess.bsky.social and @cpehlevan.bsky.social we wrote a brief perspective on how ideas about summary statistics from the statistical physics of learning could potentially help inform neural data analysis... (1/2)
frontiersin.org
Frontiers | Summary statistics of learning link changing neural representations to behavior
How can we make sense of large-scale recordings of neural activity across learning? Theories of neural network learning with their origins in statistical phy...
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Venki Murthy @neurovenki.bsky.social · 04/09/2025
Excited to share new computational work, led by @jzv.bsky.social, driven by Juan Carlos Fernandez del Castillo + contribution from Farhad Pashakanloo. We recover 3 core motifs in the olfactory system of evolutionarily distant animals using a biophysically-grounded model + efficient coding ideas!
biorxiv.org
Convergent motifs of early olfactory processing are recapitulated by layer-wise efficient coding
The architecture of early olfactory processing is a striking example of convergent evolution. Typically, a panel of broadly tuned receptors is selectively expressed in sensory neurons (each neuron exp...
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David G. Clark @david-g-clark.bsky.social · 25/08/2025
(1/26) Excited to share a new preprint led by grad student Albert Wakhloo, with me and Larry Abbott: "Associative synaptic plasticity creates dynamic persistent activity." www.biorxiv.org/content/10.1...
biorxiv.org
Associative synaptic plasticity creates dynamic persistent activity
In biological neural circuits, the dynamics of neurons and synapses are tightly coupled. We study the consequences of this coupling and show that it enables a novel form of working memory. In recurren...
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Ann Kennedy @antihebbiann.bsky.social · 20/08/2025
I wrote a Comment on neurotheory, and now you can read it! Some thoughts on where neurotheory has and has not taken root within the neuroscience community, how it has shaped those subfields, and where we theorists might look next for fresh adventures. www.nature.com/articles/s41...
nature.com
Theoretical neuroscience has room to grow
Nature Reviews Neuroscience - The goal of theoretical neuroscience is to uncover principles of neural computation through careful design and interpretation of mathematical models. Here, I examine...
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David G. Clark @david-g-clark.bsky.social · 19/08/2025
Wanted to share a new version (much cleaner!) of a preprint on how connectivity structure shapes collective dynamics in nonlinear RNNs. Neural circuits have highly non-iid connectivity (e.g., rapidly decaying singular values, structured singular-vector overlaps), unlike classical random RNN models.
arxiv.org
Connectivity structure and dynamics of nonlinear recurrent neural networks
Studies of the dynamics of nonlinear recurrent neural networks often assume independent and identically distributed couplings, but large-scale connectomics data indicate that biological neural circuit...
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Kiah Hardcastle @kiahhardcastle.bsky.social · 12/08/2025
Excited to announce that my first postdoc paper is now online! Links: www.nature.com/articles/s41... rdcu.be/eAcN7 In it, we examine the perennial question: what changes in the brain when learning a new motor skill? Read more below to find out 👇
nature.com
Differential kinematic coding in sensorimotor striatum across behavioral domains reflects different contributions to movement - Nature Neuroscience
Hardcastle and Marshall et al. show that striatal function is domain specific, required for task-related but not spontaneously expressed movements. This functional distinction is reflected in starkly ...
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David Sussillo @sussillodavid.bsky.social · 04/08/2025
Coming March 17, 2026! Just got my advance copy of Emergence — a memoir about growing up in group homes and somehow ending up in neuroscience and AI. It’s personal, it’s scientific, and it’s been a wild thing to write. Grateful and excited to share it soon.
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Viola Priesemann @violapriesemann.bsky.social · 19/07/2025
Physik studieren? Oder ein anderes Fach? In Göttingen geht jetzt beides, mit dem "Bachelor Interdisziplinär", der Physik mit spannenden Disziplinen Eurer Wahl, wie z.B. Künstlicher Intelligenz, Philosophie, Neurowissenschaften, ... kombiniert. www.uni-goettingen.de/de/studium/6...
uni-goettingen.de
Studiengang Physik interdisziplinär - Georg-August-Universität Göttingen
Webseiten der Georg-August-Universität Göttingen
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Tatiana Engel @engeltatiana.bsky.social · 25/06/2025
Out today in @nature.com: we show that individual neurons have diverse tuning to a decision variable computed by the entire population, revealing a unifying geometric principle for the encoding of sensory and dynamic cognitive variables. www.nature.com/articles/s41...
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David G. Clark @david-g-clark.bsky.social · 07/03/2025
(1/23) In addition to the new Lady Gaga album "Mayhem," my paper with Manuel Beiran, "Structure of activity in multiregion recurrent neural networks," has been published today. PNAS link: www.pnas.org/doi/10.1073/... (see dclark.io for PDF) An explainer thread...
pnas.org
Structure of activity in multiregion recurrent neural networks | PNAS
Neural circuits comprise multiple interconnected regions, each with complex dynamics. The interplay between local and global activity is thought to...
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Alexander van Meegen @avm.bsky.social · 10/06/2025
Interested in high-dim chaotic networks? Ever wondered about the structure of their state space? @jakobstubenrauch.bsky.social has answers - from a separation of fixed points and dynamics onto distinct shells to a shared lower-dim manifold and linear prediction of dynamics.
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Valentin Schmutz @bio-emergent.bsky.social · 09/06/2025
Our new preprint 👀
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Kamesh @kameshkk.bsky.social · 06/05/2025
Our work on how continuous attractors emerge in unstructured RNNs is now out in PRX Life #PRXLife : journals.aps.org/prxlife/abst... Work done with @tankutcan.bsky.social @sesamedusa.bsky.social
journals.aps.org
Emergence of Robust Memory Manifolds
Frozen stabilization enables small unstructured neural networks to form robust continuous memories and exhibit separation of timescales without fine-tuning or symmetries.
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David G. Clark @david-g-clark.bsky.social · 26/03/2025
I'll be presenting this at #cosyne2025 (poster 3-50)! I'll also be giving a talk at the "Collectively Emerged Timescales" workshop on this work, plus other projects on emergent dynamics in neural circuits. Looking forward to seeing everyone in 🇨🇦!
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Bence Ölveczky @olveczky.bsky.social · 04/03/2025
Excited to present the latest from the lab out today in Cell www.cell.com/cell/fulltex.... See Thread! 1/8
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stefanofusi.bsky.social @stefanofusi.bsky.social · 13/02/2025
We always see that 1) neural responses are very diverse 2) the shattering dimensionality is as high as it can be. Now also in an extensive analysis of the IBL dataset. Wonderful collaboration with @lorenzoposani.com, Shuqi Wang, Samuel Muscinelli, Liam Paninski. Many new analyses in this new version
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Christopher Langdon @cmlangdon.bsky.social · 12/02/2025
(1/5) Excited to share my work with @engeltatiana.bsky.social , out now in Nat Neuro! We show that RNNs use low-d latent circuit mechanisms for cognitive tasks. We find that context-dependent decisions in both RNNs and PFC arise from latent inhibitory mechanisms. www.nature.com/articles/s41...
nature.com
Latent circuit inference from heterogeneous neural responses during cognitive tasks - Nature Neuroscience
The latent circuit model identifies low-dimensional mechanisms of task execution from heterogenous neural responses. This approach reveals a latent inhibitory mechanism for context-dependent decisions...
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Tatiana Engel @engeltatiana.bsky.social · 12/02/2025
Our new paper with @chrismlangdon is just out in @natureneuro.bsky.social! We show that high-dimensional RNNs use low-dimensional circuit mechanisms for cognitive tasks and identify a latent inhibitory mechanism for context-dependent decisions in PFC data. www.nature.com/articles/s41...
nature.com
Latent circuit inference from heterogeneous neural responses during cognitive tasks - Nature Neuroscience
The latent circuit model identifies low-dimensional mechanisms of task execution from heterogenous neural responses. This approach reveals a latent inhibitory mechanism for context-dependent decisions...
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David G. Clark @david-g-clark.bsky.social · 29/01/2025
(1/30) New preprint! "Symmetries and continuous attractors in disordered neural circuits" with Larry Abbott and Haim Sompolinsky bioRxiv: www.biorxiv.org/content/10.1...
biorxiv.org
Symmetries and Continuous Attractors in Disordered Neural Circuits
A major challenge in neuroscience is reconciling idealized theoretical models with complex, heterogeneous experimental data. We address this challenge through the lens of continuous-attractor networks...
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Guillaume Bellec @bellecguill.bsky.social · 08/01/2025
Pre-print 🧠🧪 Is mechanism modeling dead in the AI era? ML models trained to predict neural activity fail to generalize to unseen opto perturbations. But mechanism modeling can solve that. We say "perturbation testing" is the right way to evaluate mechanisms in data-constrained models 1/8
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