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Lennart Wittkuhn

@lnnrtwttkhn.bsky.social
1.1K followers 984 following 58 posts

👨‍💻 Senior Specialist for Data & AI in the Public Sector | 🧠 Before: PostDoc in Computational Cognitive Neuroscience (Topics: Replay, Representations, Reproducibility) | 🏠 lennartwittkuhn.com

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Reposted by Lennart Wittkuhn
Institute for Replication @i4replication.bsky.social · 25/09/2026
Over the past two years, I4R partnered with Psychological Science (@psychscience.bsky.social) on a large reproducibility project. 67 independent teams reproduced 64 articles published in 2024–2025, about 44% of eligible papers. Paper: www.econstor.eu/bitstream/10... Here's what we learned 🧵
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 11/09/2026
Interesting story 👀 Reproducibility checks are definitely a beneficial use case for LLMs in science IMO. I recently pointed a coding agent at an old paper of mine with basically a lazy „check reproducibility“ prompt and it turned up quite useful insights. [Paper was reproducible overall, phew]
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Eric Schares @eschares.bsky.social · 31/08/2026
🚨Update: Our analysis of global APC expenditure has now been expanded to cover more publishers (7 -> 14) and more years (2019-2025). We estimate $15B in APCs paid over seven years, $3.7B in 2025 alone. Elsevier crosses the $1B threshold by itself in 2025. arxiv.org/abs/2608.16322 #ScholComm
Line chart showing 5 biggest publishers from 2019-2025
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Elise Cutts @elisecutts.bsky.social · 24/08/2026
Writing this story was so unbelievably fun. And not only bc @mcxfrank.bsky.social says quotes like this: “Kids’ experience looks really radically different than we thought ... They’ve got these little short arms, so the objects are, like, right in front of them. And they live in a forest of knees.”
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Nico Schuck @nicoschuck.bsky.social · 24/08/2026
I enjoyed writing this piece for The Transmitter. AI is a seismic change for science. What we make of it is up to us, but it’s a decision we can only make collectively. I hope more labs, and the field at large, will engage in finding a shared view of how we want to use AI.
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Danielle Navarro @djnavarro.net · 06/08/2026
The title is a little pointed, but I am very serious here. Academics, medical researchers, and other organisations should not collect data on birth sex. It is rarely relevant, and it almost always leads to privacy violations for transgender people. Please share. I would like people to read this one.
blog.djnavarro.net
Separating sex and gender is statistical malpractice – Notes from a data witch
Statisticians and academics in Australia should ignore the terrible advice of most LGBTIQA+ organisations and read this post instead. The 2020 ABS standard is almost never the correct way to collect d...
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Helen Barron @helencbarron.bsky.social · 28/07/2026
***New preprint from the lab*** showing “Generative replay across hippocampal-neocortical circuits”. In sleep we show spiking sequences in V1 (sensory neocortex!) that represent information that has not been directly experienced www.biorxiv.org/content/10.6... @bndu.ox.ac.uk @ndcnoxford.bsky.social
biorxiv.org
Generative replay across hippocampal-neocortical circuits
To make flexible decisions, the brain needs to make inferences between events that were not directly experienced together. In sharp-wave ripple (SWR) events, during periods of rest and sleep, spiking ...
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Nico Schuck @nicoschuck.bsky.social · 13/07/2026
📣Going to #cpconf? Come see @luiantaverra.bsky.social A2 Tue 9am, Bidirectional relationship between aversive beliefs + avoidance & its association with transdiagnostic symptoms @alexnitsch.bsky.social B43 Wed 3:15pm, The role of aversive replay in avoidance behaviors in psychiatric disorders
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Nico Schuck @nicoschuck.bsky.social · 07/07/2026
We're finally getting the tools to study replay in humans. But why bother? What can we learn from it that we don't know from rodent recordings? Our thoughts are now out in a new TICS Forum Great fun writing this w @smfleming.bsky.social + @maritpetzka.bsky.social authors.elsevier.com/sd/article/S...
authors.elsevier.com
What can we learn from studying replay in humans?
Noninvasive methods are making it possible to study neural replay in humans. Although focused on alignment with rodent findings, human research often …
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Simon Kern @skjerns.de · 15/06/2026
🧠 New preprint! How well can current algorithms *actually* detect neural "replay" in the human brain under absolutely optimal conditions? We built FASTIMAGES: A combined MEG + fMRI benchmark with KNOWN neural sequences, so replay-detection methods can finally be validated against a ground truth.
cimh-clinical-psychology.github.io
FASTIMAGES: Validating replay detection methods in human neuroimaging
A combined MEG + fMRI benchmark dataset with known neural sequences to validate replay detection methods (TDLM and SODA).
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 14/06/2026
I thoroughly enjoyed giving this two-day workshop on Research Data Management @rtg2753.bsky.social @uni-hamburg.de ✨ Awesome to contribute to researchers’ structured training in #OpenScience 💪 Looking for a trainer? Check out my portfolio and get in touch: lennartwittkuhn.com/consulting.h...
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 12/06/2026
@skjerns.de digs deeper into methods for non-invasive replay detection in human MEG and fMRI data. Check it out:
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Nico Schuck @nicoschuck.bsky.social · 06/05/2026
How fast agentic AI has changed our work is head-spinning and there's been a lot of debate in our lab. So we drafted guidelines to help navigate this new reality. Sharing here in the hope it’s useful for others & curious to hear thoughts schucklab.gitlab.io/ai-policy.html #AcademicSky #compneurosky
schucklab.gitlab.io
Schuck Lab — AI Policy
Schuck Lab policy on generative and agentic AI
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Simon Kern @skjerns.de · 10/04/2026
Can we really measure replay in humans using MEG with current methods? In our most recent paper we simulated replay under realistic conditions via a novel hybrid approach with astonishing results. we're delighted that it has now been published @elife.bsky.social! elifesciences.org/articles/108...
cimh-clinical-psychology.github.io
TDLM-Resting-State Simulation
How sensitive is TDLM really? Can we actually find replay when we know it is present?
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Nico Schuck @nicoschuck.bsky.social · 18/01/2026
How do we achieve few-shot generalization? New work led by @fabianrenz.bsky.social dives into the role of replay in learning and using structure to generalize reward. Dream team effort with Shany Grossman @nathanieldaw.bsky.social Peter Dayan & @doellerlab.bsky.social www.biorxiv.org/content/10.6...
biorxiv.org
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Anna Schapiro @annaschapiro.bsky.social · 15/01/2026
Really thrilled that this paper led by @neurozz.bsky.social is now published in its final version in @elife.bsky.social!! This is a memory-focused (as opposed to RL-focused) account of the detailed characteristics of forward and backward awake and sleep replay! elifesciences.org/articles/99931
elifesciences.org
A unifying account of replay as context-driven memory reactivation
A context-driven memory model simulates a wide range of characteristics of waking and sleeping hippocampal replay, providing a new account of how and why replay occurs.
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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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Andrew Heiss @andrew.heiss.phd · 15/12/2025
Grading and googling hallucinated citations, as one does nowadays, and now that LLMs have been around for a while, I've discovered new horrors: hallucinated journals are now appearing in Google Scholar with dozens of citations bc so many people are citing these fake things
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 06/12/2025
AI-generated content is a real concern. But so are overblown takes like “AI writes half the internet”. Source article has limitations (small, biased sample; English-only, crawlable pages; imperfect AI detection). Implications (e.g., for what people read online) are questionable. We need more nuance.
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Björn E. Hommel @bjoernhommel.bsky.social · 26/11/2025
🚨 SynthNet is out 🚨 Researchers propose new constructs and measures faster than anyone can track. We (@anniria.bsky.social @ruben.the100.ci) built a search engine to check what already exists and help identify redundancies; indexing 74,000 scales from ~31,500 instruments in APA PsycTests. 🧵1/3
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Emma Roscow @emmaroscow.bsky.social · 29/11/2025
New(ish) paper! It's often said that hippocampal replay, which helps to build up a model of the world, is biased by reward. But the canonical temporal-difference learning requires updates proportional to reward-prediction error (RPE), not reward magnitude 1/4 rdcu.be/eRxNz
rdcu.be
Post-learning replay of hippocampal-striatal activity is biased by reward-prediction signals
Nature Communications - It is unclear which aspects of experience shape sleep’s contributions to learning. Here, by combining neural recordings in rats with reinforcement learning, the...
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Andrew Heiss @andrew.heiss.phd · 17/11/2025
I recently discovered Conventional Comments (conventionalcomments.org) for providing a pseudo-standard set of labels for feedback and just tried it for an article review and it was really helpful to specify issues vs. thoughts vs. suggestions, etc. Hopefully it's helpful for the authors too!
We strongly suggest using the following labels:

praise:	Praises highlight something positive. Try to leave at least one of these comments per review. Do not leave false praise (which can actually be damaging). Do look for something to sincerely praise.
nitpick:	Nitpicks are trivial preference-based requests. These should be non-blocking by nature.
suggestion:	Suggestions propose improvements to the current subject. It’s important to be explicit and clear on what is being suggested and why it is an improvement. Consider using patches and the blocking or non-blocking decorations to further communicate your intent.
issue:	Issues highlight specific problems with the subject under review. These problems can be user-facing or behind the scenes. It is strongly recommended to pair this comment with a suggestion. If you are not sure if a problem exists or not, consider leaving a question.
todo:	TODO’s are small, trivial, but necessary changes. Distinguishing todo comments from issues: or suggestions: helps direct the reader’s attention to comments requiring more involvement.
question:	Questions are appropriate if you have a potential concern but are not quite sure if it’s relevant or not. Asking the author for clarification or investigation can lead to a quick resolution.
thought:	Thoughts represent an idea that popped up from reviewing. These comments are non-blocking by nature, but they are extremely valuable and can lead to more focused initiatives and mentoring opportunities.
chore:	Chores are simple tasks that must be done before the subject can be “officially” accepted. Usually, these comments reference some common process. Try to leave a link to the process description so that the reader knows how to resolve the chore.
note:	Notes are always non-blocking and simply highlight something the reader should take note of.
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Eric Schulz @ericschulz.bsky.social · 03/11/2025
🚀 We are hiring! 🚀 🔍 Join us as a Postdoctoral Researcher (fully-funded) at the Helmholtz Institute for Human-Centered AI in Munich.
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Victoria Bosch @initself.bsky.social · 03/11/2025
Introducing CorText: a framework that fuses brain data directly into a large language model, allowing for interactive neural readout using natural language. tl;dr: you can now chat with a brain scan 🧠💬 1/n
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 30/10/2025
Had a fantastic time giving a full-day workshop on Version Control with Git for Research @rtg2660.bsky.social @uni-wuerzburg.de 💫 Big thanks to organizer @leahilde.bsky.social! 🙏 As always, open materials at lennartwittkuhn.com/version-cont... 🌷
View of Marienberg Fortress across the Main river in WürzburgMonitor in a conference room with slide titled „Welcome & Introduction to Version Control“
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Russ Poldrack @russpoldrack.org · 28/10/2025
Ten Simple Rules for AI-Assisted Coding in Science arxiv.org/abs/2510.22254 - our latest, led by @ericwbridgeford.bsky.social
arxiv.org
Ten Simple Rules for AI-Assisted Coding in Science
While AI coding tools have demonstrated potential to accelerate software development, their use in scientific computing raises critical questions about code quality and scientific validity. In this pa...
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Mona Garvert @mgarvert.bsky.social · 27/10/2025
🚀 We’re hiring - Join our lab 🚀 🔍 Hiring: PhD (75% TV-L) & Postdoc (100% TV-L) 🧠 fMRI, VR, EEG, modelling We combine a range of cognitive neuroscience methods to study flexible behaviour. 📅 Start: Feb 2026 or later | ⏳ Apply by Nov 3! More details: tinyurl.com/ms3a9ajt #CognitiveNeuroscience
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Neele Elbersgerd @elbersgerd.bsky.social · 23/10/2025
If you're an undergrad student in North America, UK or Ireland, consider coming to Hamburg for a cool DAAD internship on prediction error effects on memory! Hosted by yours truly, @nicoschuck.bsky.social & @stresscognition.bsky.social. 📨 until Nov 30: Hamburg_BI_0606 www.daad.de/rise/rise-germany
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 26/10/2025
Do you know the secret to training and testing reliable cross-condition decoders in neural data? 🧠 🔍 Take part in this Kaggle challenge and win up to 1000$! 💸 Very cool idea by @skjerns.de! ✨
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Ondrej Zika @ondrejzika.bsky.social · 19/10/2025
🏡 🏳️‍🌈 ❤️ ☔ How to set up a transparent and supportive lab environment? I would love to hear from you, PIs postdocs, students! What are the things that work and that don't, what do you wish to have in place? Any examples of lab manuals? Comments, DMs or emails welcome (ondrej.zika@pm.me)
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Simon Ciranka @simyciri.bsky.social · 29/09/2025
😍 Our latest is out now in @commspsychol.nature.com. 🤩 We show with Bayesian modelling and experimental manipulation of uncertainty that developmental differences in social influence depend on differences in the internal uncertainty people have about their choice doi.org/10.1038/s442...
doi.org
Internal uncertainty impacts social information use in risky choice across adolescence - Communications Psychology
Adolescents’ choices are influenced by others. A social risky choice experiment and Bayesian modelling reveal that age differences in internal uncertainty, being unsure how to choose, relate to differences in susceptibility to social influence.
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 25/09/2025
Feeling *gitty* about this fall with two exciting workshops on Version Control with Git for Scientists coming up @mpib-berlin.bsky.social and @rtg2660.bsky.social @uni-wuerzburg.de! ✨ Sounds interesting? Check out my website, where I share course materials: lennartwittkuhn.com 💫 #OpenScience #Git
lennartwittkuhn.com
Dr. Lennart Wittkuhn | Home
Research Data Scientist
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Ondrej Zika @ondrejzika.bsky.social · 24/09/2025
🚨 I am over the moon 🌓 to announce that I am joining University College Dublin @ucddublin.bsky.social as an Assistant Professor this fall to start the Uncertain Mind (UMI) lab 💫 I am looking for PhD/Postdoc candidates to join (more below 👇 ). Please RT as the deadline is pretty soon 🙏
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Nico Schuck @nicoschuck.bsky.social · 22/08/2025
Delighted to share our work on replay and successor representations! We find replay during very short task pauses in human visual cortex that is linked to learning SRs & happens when learning is implicit. Study led by @lnnrtwttkhn.bsky.social #compneuro #neuroskyence www.pnas.org/doi/10.1073/...
pnas.org
Replay in the human visual cortex during brief task pauses is linked to implicit learning of successor representations | PNAS
Humans can implicitly learn about multistep sequential relationships between events in the environment from their statistical co-occurrence. Theore...
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 24/08/2025
Very glad to finally share our paper on replay and successor representation learning! ✨
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 03/08/2025
Check out this new preprint on factorized representations and generalization, led by the fabulous Sam Hall-McMaster (and selectively generalized bonus reading recommendations by @nicoschuck.bsky.social) ✨
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Nico Schuck @nicoschuck.bsky.social · 26/06/2025
Excited to share our latest work spearheaded by @anikaloewe.bsky.social & @maritpetzka.bsky.social. 20 min naps increased the chance to solve an insight task if sleep reached N2 stage; but the EEG spectral slope was the best predictor of insight dx.plos.org/10.1371/jour... #compneuro #psychscisky
dx.plos.org
N2 sleep promotes the occurrence of ‘aha’ moments in a perceptual insight task
Sleep supports memory consolidation, but can it also facilitate memory reorganization? This study reveals that N2 sleep, but not N1 sleep during a nap, increases the likelihood of having an 'aha' mome...
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Simon Kern @skjerns.de · 16/06/2025
preprint alert 🚨 1/ Can we accurately detect sequential replay in humans using Temporally Delayed Linear Modelling (#TDLM)? In our recent study, we could not find any replay and decided to dig deeper by running a hybrid simulation with surprising results. Link to preprint & details below 👇
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Ondrej Zika @ondrejzika.bsky.social · 21/02/2025
🚨💫🤖 RLDM Workshop announcement: "Game on: Leveraging Gamification in Cognitive and Computational Neuroscience" Contributed talks submissions now OPEN: shorturl.at/0p0Jd Looking forward to seeing you in Dublin! w/ @luiantaverra.bsky.social & @ingrdmrtn.bsky.social
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Charley Wu @thecharleywu.bsky.social · 10/02/2025
🚨 Finally out! My new @annualreviews.bsky.social in Psychology paper: www.annualreviews.org/content/jour... We unpack why psych theories of generalization keep cycling from rigid rule-based models to flexible similarity-based ones, then culminating in Bayesian hybrids. Let's break it down 👉 🧵
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 03/02/2025
Is "Git-anuary" a thing? 🤔 Committing to finally learn Git (did you git the pun)? 💫 Anyway, last month we wrapped up two great courses: Full-semester course @uni-hamburg.de & 3-day course at ZI Mannheim! lennartwittkuhn.com/news/ As always, the Git journey continues in our Version Control Book 🚀
lennartwittkuhn.com
The Version Control Book
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Luianta Verra @luiantaverra.bsky.social · 17/01/2025
It’s a Preprint! 👋 We show how we can dissociate perceptual from value-based mechanisms of generalisation + that stronger gen. in anxiety is associated with value rather than perception. w/ @ondrejzika.bsky.social @nicoschuck.bsky.social @bernhardspitzer.bsky.social osf.io/preprints/ps... 1/n
osf.io
OSF
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Ondrej Zika @ondrejzika.bsky.social · 17/01/2025
🚨💫Check out our new work on perceptual and value-based mechanisms of aversive generalisation 👇 Project led by the truly outstanding @luiantaverra.bsky.social. #veryveryveryproudsupervisor Together with @nicoschuck.bsky.social and @bernhardspitzer.bsky.social
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Christian Büchel @christianbuchel.bsky.social · 19/12/2024
Exciting PhD opportunities in various labs in Hamburg, including ours. Feel free to contact me regarding details. www.uni-hamburg.de/stellenangeb...
uni-hamburg.de
Ausschreibung
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Digital Research Academy @digiresacademy.bsky.social · 16/12/2024
🎄 Day 16 of our DRAdvent Calendar! 🎄 Comprehensive slides for a 3 hour workshop on Data Version Control, Computational Reproducibility, Good Coding Practices, and Open Platforms by DRA Trainer, @likeajumprope.bsky.social ! 💻✨ Check out Johanna’s slides here: zenodo.org/records/14268445
DRA 2023 Elf giving a thumbs up for reproducible science
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 08/12/2024
We could basically get reproducibility checks for free, if papers were computational notebooks (Jupyter, Quarto, RMarkdown, etc.), only successfully rendered versions accepted for publication and everything automated via pull request triggered CI/CD pipelines.
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 08/12/2024
„Maybe reproducibility should have a practical expiration date anyway, since it’s mostly useful around the time of publication.“ I agree. Maintaining reproducibility for decades is great but hard. It should be verified at the time of publication. But who does it? Journals? Reviewers?
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Mona Garvert @mgarvert.bsky.social · 03/12/2024
🚨Join our team! We’re hiring a PhD student in Cognitive & Clinical Neuroscience 🧠 🎓 at @uni_wue & @UKW_Wuerzburg! Explore mechanisms of decision-making in healthy people & Parkinson’s using new deep brain stimulation methods. German & English required. Apply by 20 Dec! 🌟🎄 Details: shorturl.at/IcNa0
shorturl.at
PhD_Wessel_Garvert.pdf
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 06/12/2024
Actually waiting for the answer „Code available upon reasonable request“
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Lennart Wittkuhn @lnnrtwttkhn.bsky.social · 06/12/2024
Hey #neuroskyence #compneurosky, et al., I am looking for code examples of reinforcement learning modeling in Python 🐍 I am mainly interested in *code organization* here. Thanks for any pointers to your favorite examples! 💫
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