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Simon Kern

@skjerns.de
499 followers 274 following 169 posts

Sleep & Memory researcher @ CIMH Mannheim with @gordonfeld.bsky.social . Interested in replay and applied machine learning in the context of episodic and declarative memory. MEG and Python enthusiast.

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Reposted by Simon Kern
Tony Cunningham @tonycunningham.bsky.social · 25/09/2026
Closed-loop stimulation may improve memory through more than just boosting slow waves. Grimaldi et al. found that better retention tracked the balance of slow-oscillation vs delta coupling to spindles, along with ⬆️ parasympathetic activity—not simply stronger SO–spindle coupling. buff.ly/JyhmjGn
buff.ly
Acoustic enhancement of slow wave sleep improves memory retention by coordinating brain oscillatory rhythms and autonomic activity
Sleep plays a crucial role in memory consolidation. While the interaction between sleep oscillations and autonomic activity likely influences this process,
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Reposted by Simon Kern
Ed Maibach @maibached.bsky.social · 25/09/2026
Happy Stanislav Petrov Day He passed in 2017. As Encyclopedia Britannica puts it, “He is survived by his two children, two grandchildren, and the entire human race.” If you don't know his story, please take 3 minutes now to learn it. @gchalliance.bsky.social @docsforclimate.bsky.social
sammatey.substack.com
Happy Stanislav Petrov Day
Take five minutes to not destroy civilization
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Dan Goodman @neural-reckoning.org · 23/09/2026
This is an absolutely great metaphor for explaining why experimentally figuring out what the brain is doing is hard. I may have to steal this.
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Simon Kern @skjerns.de · 16/09/2026
Yes! By now there's even a snap for easy installation: snapcraft.io/acrordrdc
snapcraft.io
Install acrordrdc (WINE) on Linux | Snap Store
Get the latest version of acrordrdc (WINE) for Linux - Adobe Acrobat Reader is a pdf reader & Web services developed by Adobe Inc.
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Simon Kern @skjerns.de · 16/09/2026
... and then there's me, trying to get Adobe DC running via wine on my KDE because Okular was too basic for many things. Different needs, different solutions! 😄
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Victoria Bosch @initself.bsky.social · 28/08/2026
Are brains and artificial neural networks converging onto universal representations? There is a seductive idea making the rounds in NeuroAI / machine learning: train systems well enough, and they all converge on the same representation of reality (i.e. a unique world model). We have thoughts™ 1/n
cell.com
The Umwelt Representation Hypothesis: rethinking Universality
Recent studies reveal striking representational alignment between artificial neural networks (ANNs) and biological brains, leading to proposals that all sufficiently capable systems converge on univer...
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Daniel Lakens @lakens.bsky.social · 28/08/2026
I care about reproducibility, but I find it deeply problematic that the British ecological society is trying to extract free labour from academics (oh no, you get free membership for a year!) to work for them for 3 years on computational reproducibility checks. apply.workable.com/britishecolo...
apply.workable.com
Associate Editor (Code Integrity and Accessibility) - British Ecological Society
Volunteer role: Associate Editor (Code Integrity and Accessibility) Organisation: British Ecological Society – Methods in Ecology and Evolution Term: 3 years Closing date: 25th Sept 17.00 BST…
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Ken Miller @kenmiller.bsky.social · 26/08/2026
This is wild. >1/2 of HC synapses disappear in artificial hibernation, come back in same/similar locations & memories intact. ~1/2 of engram synapses-between two memory-tagged cells-are clustered on dendrites, those preferentially spared. Not biggest synapses. 1/ www.science.org/doi/10.1126/...
This shows the visual abstract and a paragraph from the extended abstract of the linked article.
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Tina Lonsdorf @tinalonsdorf.bsky.social · 24/08/2026
we have an open position for a post-doc (100%) or PhD student (75%) at Bielefeld University - starting 1.11 or later (there is room for flexibility). jobs.uni-bielefeld.de/job/view/503...
jobs.uni-bielefeld.de
Research Position (m/f/d) (Postdoctoral researcher...
<p>The ‘Biological Psychology and Cognitive Neuroscience’ research group investigates human experience and behaviour at the interface betwee...
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Tim Kietzmann @timkietzmann.bsky.social · 19/08/2026
📢 We are hiring a full professor in "Intelligence in Biological and Artificial Systems". Come join us at Germany's first and largest cognitive science program. Please share far and wide, and get in touch with any questions. www.uni-osnabrueck.de/en/universit...
uni-osnabrueck.de
129 FB 8 W3 Professorship Intelligence in Biological and Artificial Systems, Institute of Cognitive Science: Uni Osnabrück
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Simon Kern @skjerns.de · 20/08/2026
Unless you explicitly mention this constraint I don't think it's okay to reject on that basis.
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Abraham Zelalem Vollan @azvollan.bsky.social · 06/08/2026
Now in Science: How does the brain’s navigation system allocate its limited representational resources during behavior? We found that grid cells sweep toward locations of interest, providing a potential mechanism for allocating spatial attention in the cognitive map.🧵 science.org/doi/10.1126/...
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Simon Kern @skjerns.de · 05/08/2026
super interesting stuff! How do you think this plays out across species (given the vast variety in breathing frequencies)?
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Martin Hebart @martinhebart.bsky.social · 01/08/2026
Come and join our replication initiative in visual neuroscience! Low bar for entry, ideal for anyone from a Master’s student looking for a thesis to faculty who want to get back to the bench. 🤓 re-vision-initiative.org
re-vision-initiative.org
re:vision | Replication Initiative for Visual Neuroscience
Test whether published visual-neuroscience findings (NSD, THINGS, etc.) generalize to broadly-sampled natural images using the LAION-fMRI (LfMRI) 7T dataset.
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Simon Kern @skjerns.de · 31/07/2026
congratulations!!!
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Simon Kern @skjerns.de · 29/07/2026
congratulations! looking forward to reading about this project :)
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Simon Kern @skjerns.de · 28/07/2026
But... why?
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Reposted by Simon Kern
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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Simon Kern @skjerns.de · 28/07/2026
Still ongoing! If you are or know a sleep researcher, please share ❤️
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Hugo Spiers @hugospiers.bsky.social · 27/07/2026
🚨 new lab preprint! Research from @gordonfeld.bsky.social during his DFG personal fellowship to my lab many moons ago: Global structure of new relational knowledge networks is represented in retrosplenial complex, and node-distance in hippocampus www.biorxiv.org/content/10.6...
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Casper Kerrén @ckerren.bsky.social · 24/07/2026
Excited to finally share our new paper in @natcomms.nature.com: Hippocampal ripples initiate cortical dimensionality expansion for memory retrieval www.nature.com/articles/s41... With @s-michelmann.bsky.social and @doellerlab.bsky.social
nature.com
Hippocampal ripples initiate cortical dimensionality expansion for memory retrieval - Nature Communications
How past experiences are reconstructed from memory remains unclear. Here the authors used intracranial EEG to show that hippocampal ripples reshape the geometry of cortical representations, supporting...
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Simon Kern @skjerns.de · 22/07/2026
Are you a sleep researcher? Then we're interested in your opinion on preregistrations! Help advance the field by filling out this short (5-minute) survey redcap.link/1zg4tezm (Any career stage, doesn't matter if you've preregistered before or not, we need you. Please share!)
redcap.link
Preregistration in Sleep Research - Practices and Barriers
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Tim Behrens @behrenstimb.bsky.social · 07/07/2026
This is one of my favourite things. Direct replication of MEG and fMRI findings in intracranial recordings and a demonstration that cortical representations update in the right direction around hippocampal ripples.
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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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Reposted by Simon Kern
Richard Sever @richardsever.bsky.social · 06/07/2026
“move from preprint to peer-reviewed publication leaves the central claims of most abstracts intact, indicating preprints are a reliable source…papers that were never posted as preprints were retracted at roughly twice the rate of those that were…” www.biorxiv.org/content/10.6...
biorxiv.org
Tracking claim changes from preprint to publication across 72,644 biomedical studies using large language models
Preprints now disseminate a large share of biomedical research before peer review. Because they have not yet passed peer review, some scientists regard preprint claims as unverified or potentially unr...
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Reposted by Simon Kern
Overly.Honest.Editor @editoratlarge.bsky.social · 29/06/2026
If you're dying with anxiety because the status of your paper has not changed from "under review" for weeks, you may want to read the Future of Peer Review report from Silverchair that came out recently and replaced the outdated Publons report from 2018... #ScientificPublishing #PeerReview /
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Simon Kern @skjerns.de · 30/06/2026
btw: do you know of anything like this, but specifically for fMRI?
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Simon Kern @skjerns.de · 30/06/2026
Should also be removed by MaxFiltering, I guess?
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Simon Kern @skjerns.de · 30/06/2026
Interesting! I always struggled to integrate the literature reports with the anecdotally observed sleep behaviour of my elderly relatives
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Reposted by Simon Kern
Liz Siefert @lizsiefert.bsky.social · 29/06/2026
New preprint! We show low arousal states promote hippocampal ripple genesis in sleep and wake. This bridges rodent work, where ripples predominate during sleep, with human studies reporting ripples during active behavior, identifying low arousal as a common mechanism www.biorxiv.org/content/10.6...
biorxiv.org
Arousal state modulates human hippocampal ripples
Hippocampal ripples are transient, high-frequency oscillations linked to memory replay and consolidation. Ripples are well-characterized in rodents to occur during periods of behavioral inactivity (i....
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Reposted by Simon Kern
Monika Schönauer @mschoenauer.bsky.social · 26/06/2026
Are the traveling dynamics of sleep slow waves functionally involved in memory consolidation? A new paper from the lab led by @norarouast.bsky.social shows that auditory stimulation during sleep disturbs SWS and affects the traveling dynamics of SWs - which mediated impaired memory consolidation!
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Maria Meier @mariame.bsky.social · 16/06/2026
Big news! 🚀 The preprint for our #NODES Delphi study is out on PsyArXiv osf.io/preprints/psyarxiv/5bt6s_v1 What's this all about? 🧵
osf.io
OSF
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Richard Sever @richardsever.bsky.social · 18/06/2026
The extent of the IF obsession is evident from any and every Google search for a journal - even venues that don't warrant one. This literally makes or breaks journals - non-profits are hit particularly hard - and it stifles innovation and distorts science. 2/2
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Health + Life Science Alliance Heidelberg Mannheim @hlsalliance.bsky.social · 17/06/2026
Meet our new Alliance Fellow Pablo Rojas! He will be working with the groups of @gordonfeld.bsky.social and Georgia Koppe www.linkedin.com/posts/health...
linkedin.com
#healthlifesciencealliance #interdisciplinaryresearch #artificialintelligence #cognitivescience #neuroscience #machinelearning #collaboration #innovation #translationalresearch #heidelberg | Health + ...
Meet our new Alliance Fellow Pablo Rojas! Could you tell us a bit about the work you do? Which field do you work in and who are your PIs? I work at the intersection of cognitive science and artificial...
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Simon Kern @skjerns.de · 15/06/2026
Thanks to everyone involved, especially @nicoschuck.bsky.social , @lnnrtwttkhn.bsky.social , @gordonfeld.bsky.social and blsky-less Elena Buß
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Simon Kern @skjerns.de · 15/06/2026
💻 Code: github.com/CIMH-Clinica... 📦 FASTIMAGES BIDS datasets on GIN: • MEG: gin.g-node.org/skjerns/FAST... • fMRI: gin.g-node.org/skjerns/FAST...
github.com
GitHub - CIMH-Clinical-Psychology/FASTIMAGES-benchmark: FASTIMAGES - MEG&fMRI benchmark for human sequence replay detection methods
FASTIMAGES - MEG&fMRI benchmark for human sequence replay detection methods - CIMH-Clinical-Psychology/FASTIMAGES-benchmark
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Simon Kern @skjerns.de · 15/06/2026
Use FASTIMAGES as a sanity check, a testbed for new methods, and a shared benchmark for human replay detection. 🧪 🌐 Project page: cimh-clinical-psychology.github.io/FASTIMAGES-b... 📄 Preprint: www.biorxiv.org/content/10.6... 💻 Code + 💾 data 👇
cimh-clinical-psychology.github.io
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Simon Kern @skjerns.de · 15/06/2026
Effect sizes are comparable in the native modality (TDLM Cohen's d ≈ 0.77). Bootstrap power analysis shows: ~20 participants × 20 trials → 80% power. As this was an absolutely best case scenario and real effects are likely much smaller, you'll likely need to go beyond that for finding real replay.
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Simon Kern @skjerns.de · 15/06/2026
SODA (built for fMRI, Wittkuhn et al. 2021) also recovers the sequences, mainly driven by the "offset" period, which is significant in every speed condition. Similarly, individual participants are not always significant, and variance between participants is high. Dependency on the decoder is less!
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Simon Kern @skjerns.de · 15/06/2026
TDLM (built for MEG, Liu et al. 2021) successfully finds significant "sequenceness" at the expected time lag in ALL four speed conditions. But variance is high! Only ~half of participants are individually significant, and sequenceness is highly correlated to decoder quality, not behaviour.
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Simon Kern @skjerns.de · 15/06/2026
You can literally see the sequence order in the averaged decoder output of the MEG and partially in the fMRI 👀 however, individual trials are much noisier. Perfect, so let's test TDLM and SODA!
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Simon Kern @skjerns.de · 15/06/2026
As a first step, we recorded a localizer, in which participants saw the five images slowly, in random order. Here, apply standard techniques to train a brain decoder that will be used later for sequence detection. Decoders work as expected ~55% in MEG (peak ~150 ms) and ~70% in fMRI (peak ~4 s).
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Simon Kern @skjerns.de · 15/06/2026
FASTIMAGES = 70 participants (30 MEG + 40 fMRI) who saw 5 images flashing in a fast sequences (132–612 ms onset-to-onset), plus localizer trials to train decoders. This produces clearly-expressed neural sequences with a KNOWN order and timing. See our project page for some animations.
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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Simon Kern @skjerns.de · 15/06/2026
The problem: Methods like TDLM & SODA are widely used to find replay, but we rarely know *if* or *when* replay actually happened. Without invasive recordings -> no ground truth. Therefore, we created a dataset that contains clear neural sequences to benchmark current algorithms.
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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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Simon Kern @skjerns.de · 14/06/2026
Are people still using RSS? For me it was initially was overwhelming and it took conscious effort to try and understand if it's useful
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Simon Kern @skjerns.de · 14/06/2026
super cool initiative, thanks for sharing! Some Feedback: The green hacker style makes it a bit difficult to use, as everything is the same font and color 😅
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Nico Schuck @nicoschuck.bsky.social · 11/06/2026
Interested in human replay and solid methods? Jointly with @skjerns.de we're releasing a benchmark dataset with known ground-truth neural sequences in MEG & fMRI, for developing & validating replay methods. First test: existing methods show similar effect sizes, but room to improve shorturl.at/6TgIr
shorturl.at
FASTIMAGES: Validating replay detection methods in human neuroimaging using a combined MEG and fMRI dataset
Studies in rodents and humans using invasive electrophysiology have established that neural replay is a ubiquitous phenomenon in the brain that is associated with a wide range of cognitive functions, ...
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Ricarda Lang @ricardalang.eurosky.social · 09/06/2026
Der Tankrabatt kostet in zwei Monaten übrigens knapp 25-mal so viel wie die von der Bundesregierung versprochene und jetzt gestoppte Erhöhung der Wohnkostenpauschale beim BAFöG.
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Daniel Gorelick @danielgorelick.bsky.social · 03/06/2026
Paying peer reviewers works. Expanded Fast & Fair experiment @biologyopen.bsky.social: • 5.5 vs 37.7 working days to decision with reviews • ~3 vs ~9 reviewer invitations per manuscript • no reduction in editor-assessed review quality • similar acceptance rates www.biorxiv.org/content/10.6...
Scatter plot showing that Fast & Fair peer review reached first decision with reviews much faster than conventional peer review: mean 5.5 versus 37.7 working days. Most Fast & Fair manuscripts met the 7-working-day target, while conventional manuscripts were slower and more variable, up to 116 working days.
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