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Nicolas Legrand

@nicolaslegrand.bsky.social
1.4K followers 1.8K following 58 posts

Senior Researcher in computational cognitive science @ Center for Humanities Computing, Aarhus University. Active inference - LLM - Reinforcement learning - Bayesian modelling | Creating a neural network library for predictive coding.

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Reposted by Nicolas Legrand
Ondrej Zika @ondrejzika.bsky.social · 15/09/2026
🚨 💫 💥 Interested in PhD / Postdoc opportunities in computational psychiatry / cognitive neuroscience? My lab at University College Dublin 🇮🇪 is currently accepting expressions of interest for internally funded PhD/Postdoc applications for positions starting in September 2027 (!). 1/
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
New preprint out of the press: 𝐂𝐚𝐫𝐝𝐢𝐚𝐜 𝐛𝐞𝐥𝐢𝐞𝐟 𝐮𝐩𝐝𝐚𝐭𝐢𝐧𝐠 𝐟𝐫𝐨𝐦 𝐯𝐨𝐥𝐚𝐭𝐢𝐥𝐞 𝐩𝐡𝐲𝐬𝐢𝐨𝐥𝐨𝐠𝐢𝐜𝐚𝐥 𝐚𝐟𝐟𝐞𝐫𝐞𝐧𝐭𝐬. A thread 🧵:
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bioRxiv Neuroscience @biorxiv-neursci.bsky.social · 11/09/2026
Cardiac belief updating from volatile physiological afferents www.biorxiv.org/content/10.64898/20…
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
Paper: www.biorxiv.org/content/10.6... Code: github.com/LegrandNico/...
biorxiv.org
Cardiac belief updating from volatile physiological afferents
Cardiac interoception is commonly assessed by comparing subjective estimates of heart rate with physiological measurements. But beliefs can easily obscure these measures, such that they cannot readily...
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
This is a work I have been carrying over years of confusion and surprise when analyzing HRD datasets, and was made ultimately possible by my Bayesian co-authors @lilweb.bsky.social & Chris Mathys.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
Here, we show what it would cost to actually measure this without leaving robust Bayesian psychophysics, the biases we can meet on the way, and how to control them. Interoceptive sensitivity is overall weak, but a clear divide is found between participants who use interoception and other beliefs.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
To summarise, the HRD is great at measuring cardiac interoceptive beliefs, but it does not inform us directly about the coupling between these beliefs and physiological signals, which is what people usually mean by “ cardiac interoception”.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
Besides the predictive performance of computational models that we usually rely on for comparison, this speaks to their cognitive relevance. If we care about the contrast between exteroceptive and interoceptive discrimination, only Bayesian filters provide this explanatory power.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
But more impressively, the final model, a hierarchical Gaussian filter, was the one that was able to 𝐧𝐞𝐚𝐫-𝐩𝐞𝐫𝐟𝐞𝐜𝐭𝐥𝐲 disentangle the two modalities of interest (interoception and exteroception) using the sensitivity estimate, which none of the other models were able to do.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
These two additional models captured significant portions of the variance, with the final comparison showing that 43% of the participants exhibited behaviours at least minimally compatible with interoceptive processing.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
In two additional models, we use weighted Bayesian updates to describe the evolution of cardiac beliefs, using either static or dynamic belief priors.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
But we also observed a large interindividual variability in this new believing ←→ interocepting axis, so we wondered if participants might not be just weak interoceptors - quite inaccurate but somehow listening to their physiological signals.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
Here, the first layer of results went against our expectations. By comparing models that assume perfect interoception versus pure believing, we find that interoceptive sensitivity is quite weak in the healthy population, with about 80% of the participants better described as "cardiac believers".
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
We then derive a computational framework that uses naturally occurring heart rate variability to quantify how strongly perceptual beliefs are updated by physiological evidence.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
We formalise interoception as weighted Bayesian updating under the joint influence of expectations and afferents, and derive a new measure, 𝐜𝐚𝐫𝐝𝐢𝐚𝐜 𝐢𝐧𝐭𝐞𝐫𝐨𝐜𝐞𝐩𝐭𝐢𝐯𝐞 𝐬𝐞𝐧𝐬𝐢𝐭𝐢𝐯𝐢𝐭𝐲, that quantifies how much beliefs shift with incoming signals.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
In this work, we tackle the second part of this problem and try to find the origin of cardiac beliefs, assuming that both internal representations and physiological inputs can carry intrinsic volatility.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
In clinical and psychological contexts, intrinsic volatility slips through sensory information and our subjective representation. If we want to develop measures of cardiac interoception, we should be interested also in how much beliefs update under new evidence.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
But this is only half of the story; by doing so, we are getting more rigorous, but we are also dropping some of the interoception itself (the strength of the connection with our heart).
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
This has motivated us to develop the Heart Rate Discrimination (HRD) task some time ago: moving away from accuracy and tracking beliefs instead, as they are the real source of confounds. doi.org/10.1016/j.bi...
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
So when you ask people about their cardiac activity, they might just be “cardiac believers” or “cardiac interoceptors” in unknown proportions...
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
This single modelling roadblock has been a source of rampant confounds across interoceptive research, but it bites especially in this modality, where sources of knowledge about heart rates are widespread in the environment.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
(In fact, I didn’t use any here; I just said 65bpm because I know this is in the range of heart rate frequency for a man of my age sitting in a chair…)
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
For example, if I had to infer my heart rate right now, I would probably say 65bpm. You can, of course, record it in real time and get a sense of how wrong/correct I am, but that doesn't tell you about the strength of my cardiac interoception.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
The objective capability to detect and report heart signals can be obscured by two hardly distinguishable cognitive strategies: either tracking the physiological signal or relying solely on prior expectation.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
But intense debates continue about the validity of experimental metrics developed over the years, in particular with the construct of cardiac interoceptive accuracy.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
Cardiac interoception has always been a first-class citizen in this field, mostly because cardiac signals are easy to record alongside subjective reports.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
Interoception, the ability to sense and interpret signals from our inner body, might play a major role in regulating behaviours and shaping subjective experience.
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Nicolas Legrand @nicolaslegrand.bsky.social · 13/09/2026
New preprint out of the press: 𝐂𝐚𝐫𝐝𝐢𝐚𝐜 𝐛𝐞𝐥𝐢𝐞𝐟 𝐮𝐩𝐝𝐚𝐭𝐢𝐧𝐠 𝐟𝐫𝐨𝐦 𝐯𝐨𝐥𝐚𝐭𝐢𝐥𝐞 𝐩𝐡𝐲𝐬𝐢𝐨𝐥𝐨𝐠𝐢𝐜𝐚𝐥 𝐚𝐟𝐟𝐞𝐫𝐞𝐧𝐭𝐬. A thread 🧵:
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Kevin J Miller @kevinjmiller.bsky.social · 03/06/2026
Computational models are a key part of science but discovering new ones is hard! DataDIVER discovers concise models from data, which surface new mechanistic ideas and clear predictions for future experiments From Google Deepmind Neuroscience Lab + collaborators www.biorxiv.org/content/10.6...
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Blake Richards @tyrellturing.bsky.social · 03/06/2026
New perspective piece with @mandanas.bsky.social: We argue, based on LLMs and old connectionist theories, that schemas shouldn't be viewed as distinct from semantic or episodic memories. They're just one end of a detailed-to-abstract memory spectrum: www.cell.com/neuron/fullt... #NeuroAI 🧠📈 🧪
cell.com
The schema spectrum: Emergent structures and levels of abstraction in AI and the brain
Motivated by generative AI, Samiei et al. argue against classical models that treat schemas as distinct memory structures. Instead, they propose that schemas are merely a conceptual tool describing ho...
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Reposted by Nicolas Legrand
Mediterranean Society for Consciousness Science @mesec-community.bsky.social · 25/04/2026
🚨 Applications are open! 🚨 Join MESEC’s 2026 Summer Workshop: ⭐️Computational Modelling for Consciousness Science: From Fragmentation to Integration⭐️ 📍 Carcassonne, France 📅 29 Aug–5 Sept 2026 🗓️ Deadline: 29 May 2026 More info and applications here: mesec.co/event/worksh...
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megan peters 🧠 @meganakpeters.bsky.social · 22/04/2026
🚨🚨JOB ALERT🚨🚨 I'm hiring a cogsci/philosophy/compneuro postdoc at @ucl.ac.uk @uclbrainscience.bsky.social @uclpals.bsky.social! www.jobs.ac.uk/job/DRH486/p... Come to London & work on frameworks for "testing" for consciousness using Bayesian belief updating & latent variable modeling. Pls share!
jobs.ac.uk
Postdoctoral Research Fellow at UCL
Discover Postdoctoral Research Fellow jobs and more in higher education on jobs.ac.uk. Apply for further details on the top job board.
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Maria Leonor Pacheco @mlpacheco.bsky.social · 17/04/2026
Would love to get some colleagues at the intersection of NLP and CogSci. Reach out if you have any questions! Deadline: 31-Jul-2026
jobs.colorado.edu
Assistant Professor in Cognitive Science, AI & the Mind
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Nicolas Legrand @nicolaslegrand.bsky.social · 16/04/2026
𝐍𝐞𝐰 𝐏𝐲𝐇𝐆𝐅 𝐫𝐞𝐥𝐞𝐚𝐬𝐞 (𝐯0.2.10), featuring an early draft of local-only deep predictive coding networks. Get prospective configuration-like behaviours for a fraction of the compute cost. Work in progress... 📦Code: github.com/Computationa... 📓Tutorial: computationalpsychiatry.github.io/pyhgf/notebo...
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Thomas Andrillon @thomasandrillon.bsky.social · 09/04/2026
New article with @oudietted.bsky.social and the @dreamteamicm.bsky.social Dream-like mental states can occur during wakefulness Published now in @cp-cellreports.bsky.social www.cell.com/cell-reports... Congrats to Nicolas Decat!
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ExplainableML @eml-munich.bsky.social · 12/02/2026
🥳Happy to share that we have three papers accepted to #ICLR2026. Congrats to our authors and see you in Rio🌴🇧🇷. Check the thread for highlights👇
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Sam Gershman @gershbrain.bsky.social · 09/01/2026
With some trepidation, I'm putting this out into the world: gershmanlab.com/textbook.html It's a textbook called Computational Foundations of Cognitive Neuroscience, which I wrote for my class. My hope is that this will be a living document, continuously improved as I get feedback.
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Lilian Weber @lilweb.bsky.social · 18/12/2025
🚀 Excited to announce that I'm looking for people (PhD/Postdoc) to join my Cognitive Modelling group @uniosnabrueck.bsky.social. If you want to join a genuinely curious, welcoming and inclusive community of Coxis, apply here: tinyurl.com/coxijobs Please RT - deadline is Jan 4‼️
uni-osnabrueck.de
192 FB 8/IKW Research Associate (m/f/d), Institute of Cognitive Science: Uni Osnabrück
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Sarah Garfinkel @sarahgarf.bsky.social · 24/11/2025
** Recruiting a postdoc ** We are looking for a postdoc to work on emotion, mental health, and interoception, based in London at @ucl.ac.uk in my lab (Clinical and Affective Neuroscience). Part of a large Wellcome Grant (co-led with the brilliant @camillanord.bsky.social)
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Jonathan A. Michaels @jonathanamichaels.bsky.social · 29/10/2025
Thrilled that our paper is out today in Nature! www.nature.com/articles/s4...
nature.com
Sensory expectations shape neural population dynamics in motor circuits
Nature - Experiments with human volunteers and macaques show that expectations produced by probabilistic cueing of future sensory inputs shape motor circuit dynamics in order to increase the...
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Ida Momennejad @neuroai.bsky.social · 27/10/2025
Pleased to share new work with @sflippl.bsky.social @eberleoliver.bsky.social @thomasmcgee.bsky.social & undergrad interns at Institute for Pure and Applied Mathematics, UCLA. Algorithmic Primitives and Compositional Geometry of Reasoning in Language Models www.arxiv.org/pdf/2510.15987 🧵1/n
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Matthew Finlayson @mattf.nl · 17/10/2025
We discovered that language models leave a natural "signature" on their API outputs that's extremely hard to fake. Here's how it works 🔍 📄 arxiv.org/abs/2510.14086 1/
arxiv.org
Every Language Model Has a Forgery-Resistant Signature
The ubiquity of closed-weight language models with public-facing APIs has generated interest in forensic methods, both for extracting hidden model details (e.g., parameters) and for identifying...
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The Viking (Gunnar Blohm) @gunnarblohm.bsky.social · 04/10/2025
www.nature.com/articles/s41...
nature.com
A brain-inspired agentic architecture to improve planning with LLMs - Nature Communications
Multi-step planning is a challenge for LLMs. Here, the authors introduce a brain-inspired Modular Agentic Planner that decomposes planning into specialized LLM modules, improving performance across tasks and highlighting the value of cognitive neuroscience for LLM design.
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Trends in Cognitive Sciences @cp-trendscognsci.bsky.social · 26/09/2025
Online Now: Cognitive modeling of real-world behavior for understanding mental health
dlvr.it
Cognitive modeling of real-world behavior for understanding mental health
A core strength of computational psychiatry is its focus on theory-driven research, in which cognitive processes are precisely quantified using computational models that formalize specific theoretical mechanisms. However, the data used in these studies often come from traditional laboratory-based cognitive tasks, which have unclear ecological validity. In this review we propose that the same theoretical frameworks and computational models can be applied to real-world data such as experience sampling, passive data, and digital-behavior data (e.g., online activity such as on social media). In turn, modeling real-world data can benefit from a theory-driven computational approach to move from purely predictive to explanatory power. We illustrate these points using emerging studies and discuss the challenges and opportunities of using real-world data in computational psychiatry.
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Kobe Desender @kobedesender.bsky.social · 25/09/2025
Introducing hMFC: A Bayesian hierarchical model of trial-to-trial fluctuations in decision criterion! Now out in @plos.org Comp Bio. led by Robin Vloeberghs with @anne-urai.bsky.social Scott Linderman Paper: desenderlab.com/wp-content/u... Thread ↓↓↓ #PsychSciSky #Neuroscience #Neuroskyence
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Milena Rmus @milenamr7.bsky.social · 22/09/2025
Happy to announce our paper got accepted to #NeurIPS! @akjagadish.bsky.social @marvinmathony.bsky.social @ericschulz.bsky.social & Tobi Ludwig arxiv.org/abs/2502.00879
arxiv.org
Generating Computational Cognitive Models using Large Language Models
Computational cognitive models, which formalize theories of cognition, enable researchers to quantify cognitive processes and arbitrate between competing theories by fitting models to behavioral data....
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Nicolas Legrand @nicolaslegrand.bsky.social · 16/09/2025
If you are concerned with performance, I also recommend checking out SleepECG (Systole uses their version of the Pan-Tompkins algorithm under the hood) : sleepecg.readthedocs.io/en/stable/
sleepecg.readthedocs.io
SleepECG
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Nicolas Legrand @nicolaslegrand.bsky.social · 16/09/2025
If you want to report bugs or ask questions, you can reach out here: github.com/LegrandNico/...
github.com
GitHub - LegrandNico/systole: Systole: A python package for cardiac signal synchrony and analysis
Systole: A python package for cardiac signal synchrony and analysis - LegrandNico/systole
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Nicolas Legrand @nicolaslegrand.bsky.social · 16/09/2025
Hi @koeniglab.bsky.social ! Thanks for the shout-out. I created Systole while I was a postdoc in the ECG lab, but since I left a few years ago, I am no longer actively maintaining it at the moment.
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hakwan lau @hakwan.bsky.social · 01/09/2025
does someone good at coding & analysis want to work remotely w/ us in the coming few months (before end of 2025), as a paid consultant? project will be on neurofeedback (fMRI, ECoG, calcium imaging). we'll work towards developing the experiments & analysis pipelines together. if so pls DM me ur CV🧠📈
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