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Payam Piray

@payampiray.bsky.social
1.6K followers 328 following 33 posts

Computational neuroscientist. Assistant professor @USC psychology. Previously @Princeton and @Donders www.piraylab.com

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Reposted by Payam Piray
Armin Bazarjani @arminbazza.bsky.social · 05/10/2026
I'm excited to share that our paper "Default Feature Representations of the Cognitive Map" has been accepted to #NeurIPS2026! 🧵
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Payam Piray @payampiray.bsky.social · 25/09/2026
The lab had 4 out of 4 papers accepted at NeurIPS. More on each one soon. We also have postdoc openings funded by our new grants, so email me if you're interested in our research. usccareers.usc.edu/job/los-ange...
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Payam Piray @payampiray.bsky.social · 28/08/2026
I am happy to share some good news: my lab has received an NSF CAREER award and an NIH R01 this summer, supporting our work on how the brain handles uncertainty during learning. We will be hiring postdocs and PhD students in the coming year, so please get by email in touch if you are interested.
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Seth Pollak @sethpollak.bsky.social · 18/06/2026
Why do stressful childhood experiences lead people to make maladaptive choices? This study suggests early experiences lead individuals to expect environments to be volatile, explaining why their decisions feel appropriate to them. shorturl.at/e0tZC 🧪 @kesmith.bsky.social @payampiray.bsky.social
Teenagers red high-tops standing in front of arrows pointing in many directions
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Payam Piray @payampiray.bsky.social · 25/05/2026
Fantastic, congrats!
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Payam Piray @payampiray.bsky.social · 11/03/2026
However, about 50% of the reviewed studies did not report effect size in terms of model frequency (did fixed effect), which makes such post hoc power analysis virtually impossible without a complete re-analysis.
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Payam Piray @payampiray.bsky.social · 11/03/2026
The shared python library can also be configured with a user-input effect size. I agree that the best “post hoc” practice is to use the observed effect size, which can be easily used with the proposed method for power analysis, and it is highlighted in the discussion.
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Payam Piray @payampiray.bsky.social · 11/03/2026
Sounds interesting, thank you for sharing. There is a secondary analysis in the paper with different assumptions about the effect size, which is a bit more in line with your conclusion (Ext fig 1). That analysis corresponds to a medium effect size per cohen.
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Reposted by Payam Piray
Ali Mahmoodi @alimahmoodi.bsky.social · 16/02/2026
We review studies showing that when brain areas face similar computational demands in social and non-social context, they perform the same computations. We argue that exaptation (repurposing of traits for new functions) played a key role in brain evolution.
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Jonathan Nicholas @jonathannicholas.bsky.social · 23/01/2026
Our experiences have countless details, and it can be hard to know which matter. How can we behave effectively in the future when, right now, we don't know what we'll need? Out today in @nathumbehav.nature.com , @marcelomattar.bsky.social and I find that people solve this by using episodic memory.
nature.com
Episodic memory facilitates flexible decision-making via access to detailed events - Nature Human Behaviour
Nicholas and Mattar found that people use episodic memory to make decisions when it is unclear what will be needed in the future. These findings reveal how the rich representational capacity of episod...
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Reposted by Payam Piray
tafazolisina.bsky.social @tafazolisina.bsky.social · 11/02/2026
Thrilled that my paper is out in the @nature.com. We explored how the brain builds complex tasks by compositionally combining simpler sub-task representations. The brain flexibly performs multiple tasks by dynamically reusing neural subspaces for sensory inputs and motor actions rdcu.be/eRVUk
rdcu.be
Building compositional tasks with shared neural subspaces
Nature - The brain can flexibly perform multiple tasks by compositionally combining task-relevant neural representations.
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Payam Piray @payampiray.bsky.social · 16/02/2026
Huge congrats Sina!
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Payam Piray @payampiray.bsky.social · 17/11/2025
Thank you! Yeah the results are based on xp (and not protected xp). I’ve also introduced a new method for determining critical values of xp by controlling false positives; the commonly assumed 0.95 critical value for either xp or pxp can be misleading in my view (usually too conservative).
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Payam Piray @payampiray.bsky.social · 17/11/2025
I argue that we need to account for the size of the model space when determining sample size, as larger model spaces reduce power. I also show that the commonly used “fixed effects” model selection approach is statistically unreliable. An analysis of the literature suggests shortcomings in both
Estimated power for 52 reviewed studies based on their sample sizes and model space sizes. Among these, 41 studies fell below the standard 0.8 power threshold. About half of these studies used fixed effect model selection approach.
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Payam Piray @payampiray.bsky.social · 17/11/2025
Happy to share my new paper published in @nathumbehav.nature.com: A critical look at statistical power in computational modeling studies, particularly those based on model selection. www.nature.com/articles/s41...
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Alicia Izquierdo @aliciaizquierdo.bsky.social · 08/10/2025
🎇 Excited to finally share JL Romero Sosa’s publication! Results are from single-cell imaging in different subregions of rat frontal cortex during ✨de novo learning. Spoiler: everything is not everywhere all at once www.nature.com/articles/s41...
nature.com
Neural coding of choice and outcome are modulated by uncertainty in orbitofrontal but not secondary motor cortex - Nature Communications
Neural mechanisms underlying flexible learning and decision-making are not fully understood. Using single-cell calcium imaging, authors here found that neurons in orbitofrontal and secondary motor cortex exhibit complementary roles in reward learning, with neurons in the former exerting a sustained role in conditions of uncertainty.
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Amanda Kay Montoya @akmontoya.bsky.social · 13/08/2025
Good news of the front of restoring UCLA's grants! calmatters.org/education/20...
calmatters.org
Federal judge orders Trump administration to restore hundreds of UCLA research grants
The grants were terminated over alleged DEI violations. University of California attorneys argued the actions were arbitrary and capricious.
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Payam Piray @payampiray.bsky.social · 12/08/2025
More generally, we link MEC coding to planning-ready compositional representations, with invariant and modular responses in ubiquitous MEC object vector cells. These cells provide the building blocks of compositionality in the model.
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Payam Piray @payampiray.bsky.social · 12/08/2025
Neurally, influential work proposed grid cells encode eigenvectors of the successor map. Nice idea, but it struggles when barriers or goals change. Our model ties grid code to the compositional map, keeping them useful even as the world changes, consistent with empirical findings on local remapping.
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Payam Piray @payampiray.bsky.social · 12/08/2025
Computationally, the model builds a successor map piece by piece, by putting together representations related to barriers and goals. We propose translation/rotation-invariant code for representation of task components (objects/goals) that plans near-optimally in complicated navigation tasks.
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Payam Piray @payampiray.bsky.social · 12/08/2025
New paper with @nathanieldaw.bsky.social in Nature Communications: an RL model that builds a successor map compositionally. The new model plans as well as the best models, and it links components of the map used for planning to neural codes in the medial entorhinal cortex. rdcu.be/eAofi
rdcu.be
Reconciling flexibility and efficiency: medial entorhinal cortex represents a compositional cognitive map
Nature Communications - How the brain creates compositional cognitive maps that support both flexible and efficient planning remains poorly understood. Here, authors propose a...
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Dean Buonomano @deanbuono.bsky.social · 01/08/2025
It looks like all NSF/NIH grants to UCLA (including mine and all fundamental neuroscience grants) have been suspended. www.science.org/content/arti...
science.org
NSF and NIH suspend grants to UCLA
Move follows Trump administration finding that school didn’t effectively combat antisemitism
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Sam Nastase @samnastase.bsky.social · 07/07/2025
Check out Zaid's open "Podcast" ECoG dataset for natural language comprehension (w/ Hasson Lab). The paper is now out at Scientific Data (nature.com/articles/s41...) and the data are available on OpenNeuro (openneuro.org/datasets/ds0...).
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Marcelo Mattar @marcelomattar.bsky.social · 02/07/2025
Thrilled to see our TinyRNN paper in @nature! We show how tiny RNNs predict choices of individual subjects accurately while staying fully interpretable. This approach can transform how we model cognitive processes in both healthy and disordered decisions. doi.org/10.1038/s415...
doi.org
Discovering cognitive strategies with tiny recurrent neural networks - Nature
Modelling biological decision-making with tiny recurrent neural networks enables more accurate predictions of animal choices than classical cognitive models and offers insights into the underlying cog...
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Payam Piray @payampiray.bsky.social · 03/07/2025
Great great work, congrats!
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Reposted by Payam Piray
Nina Rouhani @ninarouhani.bsky.social · 29/05/2025
new paper from a collaborative endeavor! (@co0p3r.bsky.social) we find & replicate food-reward biases in a reinforcement learning task (where food stim are incidental) people with eating disorder symptoms show a low-calorie food bias while those without show a high-calorie food bias... (1/3)
nature.com
Eating disorder symptoms and emotional arousal modulate food biases during reward learning in females - Nature Communications
Disordered eating can disrupt the rewarding value of food. Here, the authors show in a female sample that eating disorder symptoms, emotional arousal, and interoceptive awareness modulate goal-ir...
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Payam Piray @payampiray.bsky.social · 08/05/2025
So happy for you, congratulations!
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Shervin Safavi @neuroprinciplist.bsky.social · 20/02/2025
Re-posting is appreciated: We have a fully funded PhD position in CMC lab @cmc-lab.bsky.social (at @tudresden_de). You can use forms.gle/qiAv5NZ871kv... to send your application and find more information. Deadline is April 30. Find more about CMC lab: cmclab.org and email me if you have questions.
forms.gle
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Payam Piray @payampiray.bsky.social · 15/03/2025
So so sorry for you loss. That’s a beautiful piece!
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Morteza Dehghani @mdehghani.bsky.social · 20/02/2025
Very cool work on the intersection of interpretability and multi-lingual LLMs, led by @elnaz-rahmati.bsky.social
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Morteza Dehghani @mdehghani.bsky.social · 19/02/2025
Our new paper explores how to align LLMs with System 1 (intuitive) and System 2 (analytical) thinking styles. This work challenges the idea that step-by-step reasoning (CoT) is always best and highlights the need for adapting reasoning strategies based on the task arxiv.org/abs/2502.12470
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Nathaniel Daw @nathanieldaw.bsky.social · 05/02/2025
hello world. we have an opening for a strong theory postdoc to work in my lab on a exciting collaboration with Josh Berke and Loren Frank labs modeling and analyzing data on rat hipp-pfc-bg-da involvement in spatial maze foraging, replay, value etc. apply here: www.princeton.edu/acad-positio...
princeton.edu
Application for Postdoctoral Research Associate
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Quentin Huys @docqhuys.bsky.social · 09/01/2025
Poster submissions for the Computational Psychiatry Conference 2025 in Tübingen are now open. Deadline is 7th February. Symposium submissions are open until 15th January. www.cpconf.org. Please RB.
cpconf.org
Computational Psychiatry Conference
Tübingen, Germany (July 14-16, 2025)
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Morteza Dehghani @mdehghani.bsky.social · 17/01/2025
(1/4) Our new JEP:G paper dives into how moral values and misinformation spread on social media: media.mola-lab.org/file/1737039...
media.mola-lab.org
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Kate Nussenbaum @katenuss.bsky.social · 02/12/2024
I'm hiring a full-time lab manager / research tech for my new psychology lab at Boston University, to start this summer (July 2025)! The lab's research focuses on understanding developmental changes in learning, memory, and exploration. More details here: cldlab.org/join/ 🧠💻 #psychscisky
Detailed job description, which can also be found here: https://cldlab.org/join/
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Tim Behrens @behrenstimb.bsky.social · 01/12/2024
OK If we are moving to Bluesky I am rescuing my favourite ever twitter thread (Jan 2019). The renamed: Bluesky-sized history of neuroscience (biased by my interests)
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Payam Piray @payampiray.bsky.social · 25/11/2024
Am I qualified as a cognitive controller?
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Brad Wyble @bwyble.bsky.social · 24/11/2024
Neuromatch is looking for a curriculum specialist for our #neuroAI course. Spread the word! acrobat.adobe.com/id/urn:aaid:...
acrobat.adobe.com
Adobe Acrobat
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Payam Piray @payampiray.bsky.social · 22/11/2024
🙋🏻
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Payam Piray @payampiray.bsky.social · 21/11/2024
Me too please!
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RLDM @rldmparis2027.bsky.social · 15/11/2024
Come join us at Trinity College Dublin for the 6th Multidisciplinary Conference on Reinforcement Learning and Decision Making (RLDM2025) Abstract deadline January 15: rldm.org/submit
Picture of Trinity College Dublin's campanile in the front square of the college. Writing overlayed to indicate that the RLDM conference will take place from the 11th to the 14th of June, 2025. Logos for Trinity College and the RLDM conference at the bottom of the image.
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Payam Piray @payampiray.bsky.social · 17/11/2024
I’d like to be added too
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Payam Piray @payampiray.bsky.social · 15/11/2024
Thanks! If it is not too late, I’d like to be added too
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Payam Piray @payampiray.bsky.social · 14/11/2024
This sounds like a great course. Thank you!
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Payam Piray @payampiray.bsky.social · 12/11/2024
Thanks. I’d be happy to be added too
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Claire Gillan @clairegillan.bsky.social · 11/11/2024
Did you know #RLDM2025 is coming to Dublin next June? rldm.org Abstract submission open now ☘️ 🇮🇪
rldm.org
RLDM | The Multi-disciplinary Conference on Reinforcement Learning and Decision Making
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Payam Piray @payampiray.bsky.social · 11/11/2024
And please add me to your starter packs!
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Payam Piray @payampiray.bsky.social · 11/11/2024
X’s (it is definitely X not twitter) “For you” tab should be called 'Not for you'! Meanwhile, Bluesky feels like a cozy science cafe! 🧠☕️ Computational neuro/psychiatry folks, NeuroAI enthusiasts, cognitive science/neuroscience students - let's build this community!
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Payam Piray @payampiray.bsky.social · 11/11/2024
Thanks! I’d like to be added too!
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Payam Piray @payampiray.bsky.social · 11/11/2024
This is super useful. Thank you!
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