Alireza Karami | علیرضا کرمی

The Journal of Neuroscience: 45 (28)

Excited to share our JNeurosci paper- featuring on the cover!
The Representational Organization of Static and Dynamic Visual Features in the Human Cortex
w/ Jianxin Wang, and Stefano Anzellotti
Cover: www.jneurosci.org/content/45/28.cover-expansion
Paper: www.jneurosci.org/content/45/28/e1164242025

A computational linguistics colleague needed to join the Center for Mind-Brain Sciences - Italy's leading cognitive neuroscience research unit. @cimecunitrento.bsky.social is located in Trentino, famous for its high quality of life in Italy. www.cimec.unitn.it/en/71/langua...

Looking for a Master internship and interested in timing the interplay between timing and hearing?
🔽
brainthemind.com/openings/

Seeing the Mind, Educating the Brain

If you are in Paris on October 1-3 : we are organizing a fantastic cognitive neuroscience conference at Collège de France, on topics ranging from language to math, education and consciousness, with many of my favorite scientists !
Full program here:
www.unicog.org/seeing-the-m...

Distinct neural representational geometries of numerosity in early visual and association regions across visual streams - Communications Biology This study reveals distinct neural codes for visual numerosity across the brain, showing that numerosity is independently represented from early visual areas to higher-level regions along both dorsal ...

Huge thanks to the @cimecunitrento.bsky.social fMRI lab, and to Ben Harvey and Florent Meyniel for inspiring discussions. 🙏

And of course, to the participants who made this work possible.

Read the full paper here:
🔗 www.nature.com/articles/s42...

💬 Curious to discuss? My DMs are open!

Exciting avenues ahead:
✅ Developmental studies—do these ventral representations emerge early or with formal education?
✅ Cross-modal generalization—does the same geometry hold for other sensory modalities?
✅ Links to behavior—how do these neural patterns relate to numerical skills?

🌟 Our results challenge the idea that numerosity is mainly a dorsal stream function.

Ventral areas also show robust encoding—suggesting a more distributed system than @standehaene.bsky.social ’s Triple Code Model.

This raises new questions about symbolic and non-symbolic number processing.

• Early visual areas showed a linear number line.
• Parietal and ventral regions showed a curved manifold, separating extremes from middle numerosities.

Possible interp.:
🔸 Numerosity-tuned coding @jacobmpaul.bsky.social aul.bsky.social‬
🔸 Decision-variable encoding @summerfieldlab.bsky.social

🧠 We replicate Castaldi et al. (2019), showing numerosity is encoded independently of other visual features along the dorsal stream.

🔍 We extend this to the ventral stream, where number representations were often neglected, aligning with topographic maps reported by @sergedumoulin.net & Harvey.

Our approach built on Castaldi et al. (2019) and combined:
🔹 RSA—to quantify how numerical and non-numerical features are encoded
🔹 Multidimensional Scaling (MDS)—to visualize the neural geometry of numerosity representations

This allowed us to isolate number representations from visual confounds.

We used fMRI in 31 adults performing a numerosity estimation task.
Visual arrays varied in:
• Number of dots
• Item size
• Total area
• Density

✅ Critically controlled for visual confounds to isolate genuine number representations.

Why care about numerosity?
Numerosity perception is a core cognitive skill:
• Present early in development
• Shared across species
• Thought to scaffold formal math learning

Yet, where and how the brain encodes it independently of other visual features has remained debated.

New paper out in @commsbio.nature.com!
@elicastaldi.bsky.social, Evelyn Eger, @manpiazza.bsky.social

🔢 We reveal how the brain represents numerosity across the entire visual system, from early visual areas to high-level association cortices.

👇 A thread
🔗 www.nature.com/articles/s42...

🎉 New Chapter Published!

🧠 Title:
Neurobiological underpinnings of developmental dyscalculia
👥 Authors:
Paula A. Maldonado Moscoso, @alirezakr.bsky.social , @manpiazza.bsky.social

#Neuroscience #CognitiveNeuroscience #LearningDisabilities #Dyscalculia

New article out featuring CIMeC researchers Alireza Karami and Manuela Piazza, in collaboration with Elisa Castaldi and Evelyn Eger!

@alirezakr.bsky.social, @manpiazza.bsky.social

Read more 👇🏻
www.nature.com/articles/s42003-025-08395-z

Distinct neural representational geometries of numerosity in early visual and association regions across visual streams - Communications Biology This study reveals distinct neural codes for visual numerosity across the brain, showing that numerosity is independently represented from early visual areas to higher-level regions along both dorsal ...

This study reveals distinct neural codes for visual numerosity across the brain, showing that numerosity is independently represented from early visual areas to higher-level regions along both dorsal and ventral streams. www.nature.com/articles/s42...

🔗 Read more here:
👉 tinyurl.com/muw8aeta

🔍 What’s it about?
Developmental dyscalculia is a learning disorder where children struggle with math despite normal intelligence and typical development.
✨ Key Highlights:
Consistent evidence of structural and functional changes in the right parietal cortex & its connections to frontal regions.

📚 Published in:
Developmental Dyscalculia: From Brain Mechanisms to Educational Applications
Edited by Yarden Gliksman, Liane Kaufmann, and Avishai Henik

🎉 New Chapter Published!

🧠 Title:
Neurobiological underpinnings of developmental dyscalculia
👥 Authors:
Paula A. Maldonado Moscoso, @alirezakr.bsky.social , @manpiazza.bsky.social

#Neuroscience #CognitiveNeuroscience #LearningDisabilities #Dyscalculia

What Counts as Discovery? Rethinking AI’s Place in Science

🔍 “Discovery isn’t just spotting patterns—it’s reframing them into new ideas.”

In “What Counts as Discovery?”, Nisheeth Vishnoi argues that AI can fit data to existing models, but only humans make the true conceptual leap.

🧠🤖 We’re hiring a Postdoc in NeuroAI!

Join CRC1233 "Robust Vision" (Uni Tübingen) to build benchmarks & evaluation methods for vision models, bridging brain & AI. Work with top faculty & shape vision research.

Apply: tinyurl.com/3jtb4an6

#NeuroAI #Jobs

Three must read papers for PhD students. #scisky #PhD #science #research #academicsky

1. The importance of stupidity in scientific research

Open Access
journals.biologists.com/jcs/article/...

But to your question about guidelines, this one from NIH could be useful

I'm starting to work on a new library, "clustrix" (
clustrix.readthedocs.io/en/latest/) to ease switching between local vs. remote execution in Python scripts, notebooks, etc. This has been a pain point for my group for a while!

Dimensions underlying the representational alignment of deep neural networks with humans - Nature Machine Intelligence An interpretability framework that compares how humans and deep neural networks process images has been presented. Their findings reveal that, unlike humans, deep neural networks focus more on visual ...

What makes humans similar or different to AI? In a paper out in @natmachintell.nature.com led by @florianmahner.bsky.social & @lukasmut.bsky.social, w/ Umut Güclü, we took a deep look at the factors underlying their representational alignment, with surprising results.

www.nature.com/articles/s42...

"Large [language] models should not be viewed primarily as intelligent agents but as a new kind of cultural and social technology, allowing humans to take advantage of information other humans have accumulated." henryfarrell.net/wp-content/u...

My take on Registered Reports in psychology:

Without them:
🔹 Theories seem stronger than they are
🔹 Null results vanish
🔹 The replication crisis grows

With them:
✅ We see what actually works
✅ Science gets honest
✅ Progress becomes real

New in LayNii v2.9.0: Introducing *LayNii IDA*, a high-performance tool for real-time interaction with ultra–high resolution MRI data. Built for speed, designed for discovery. Still early, but a big step toward the next era of 7T fMRI: higher resolution, larger datasets.

github.com/layerfMRI/La...

A vector calculus for neural computation in the cerebellum Null space theory predicts that neurons generate spikes not only to produce behavior but also to prevent the undesirable effect of other neurons on behavior. In this work, we show that this competitiv...

Neuronal computation in the cerebellum via a vector calculus.

Work of Mohammad Amin Fakharian, Alden Shoup, Paul Hage, and Hisham Elseweifi

www.science.org/doi/10.1126/...