Alex Williams

Need to also keep in mind that most of these numbers on PCA embedding dimension are based on trial averages often with a good deal of temporal smoothing via convolution with a gaussian filter

This week the Trump CDC attacked science — and our health, and our kids’ health — by twisting the truth on the CDC website.

There’s things to say about the playbook they used, and that’s helped by a little explanation about scientific truth in practice.

New vid explainer from me:
🧪 part 1/

Low rank adaptation of chemical foundation models generate effective odorant representations Featurizing odorants to enable robust prediction of their properties is difficult due to the complex activation patterns that odorants evoke in the olfactory system. Structurally similar odorants can ...

🔔 NEW PREPRINT FROM THE LAB ‼️
We introduce a new ML model, LoRAX, for predicting olfactory responses from chemical features, a tricky problem that benefits from progress in ML for biochem. We combine LoRA fine-tuning with protein and chemical foundation models, www.biorxiv.org/content/10.1...

As a longtime fan of cool papers in @currentbiology.bsky.social, I am really thrilled to see this out!

This study sets the stage for understanding the origins of novel (vocal) behaviors.

Big shout out to the main architects of this work @xmikezheng20.bsky.social and @cliffscience.bsky.social

Lighting and circadian cues shape locomotor strategies for balance and navigation in larval zebrafish Most fish are inherently unstable and must swim to stabilize posture. How diurnal fish reduce activity at night while maintaining postural control remains unclear. We defined distinct locomotor strate...

Like most animals, fish move less at night. Underwater, stable posture requires movement. Find out how fish don't fall down at night in: Lighting and circadian cues shape locomotor strategies for balance and navigation in larval zebrafish from @yunluzhu.bsky.social
doi.org/10.1101/2025...

Excited to share this work where we found how fish swim differently to keep balance in the dark / explore more in the light.

Spoiler: ever wonder what they do during “little pauses” between swims? They are counting!

The UniReps Workshop accepted papers are out! 🎉
Huge thanks to the authors, reviewers, and incredible AC committee for their dedication and effort in making this happen. 🙏 openreview.net/group?id=Neu...

Note: this has a computational scientist track! It’s for you, too, math nerds!

Congrats Cole!

Hearing a rumor that NIH/HHS may now plan to retaliate against other Bethesda Declaration signers.

I am one, but it’s not about me: we have been speaking out because of the ongoing damage to US medical research, cancer and Alzheimer’s research.

As @jenna-m-norton.bsky.social put well: 1/

Our new paper in @natcomms.nature.com introduces improv, a flexible software platform that integrates models with experiments in real-time. Traditional experiments collect all data first, then analyze it later. With improv, models analyze data as it streams in and actively guide what to do next.

I entirely agree.

Research in rodents has enabled remarkable technical advances and deepened our understanding of brainstem circuits and general brain physiology.

However, only NHPs possess cognitive, visual, and motor faculties necessary to advance human-relevant systems neuroscience.

Estrogen modulates reward prediction errors and reinforcement learning - Nature Neuroscience Dopamine encoding of reward prediction errors naturally fluctuates over females’ reproductive cycles with estrogenic signaling due to reduced expression of dopamine reuptake proteins.

Thrilled to share our new paper, out now in @natneuro.nature.com, uncovering how estradiol, the most potent estrogen, modulates reinforcement learning and reward prediction errors across biological levels. www.nature.com/articles/s41...

#blueprint 1/7

Our next paper on comparing dynamical systems (with special interest to artificial and biological neural networks) is out!! Joint work with @annhuang42.bsky.social , as well as @satpreetsingh.bsky.social , @leokoz8.bsky.social , Ila Fiete, and @kanakarajanphd.bsky.social : arxiv.org/pdf/2510.25943

Congratulations Martin! Well deserved!

ATTN: Two faculty positions are available in my department (neuroscience) at the University of Minnesota. This is a general search with no topic focus. November 20th application deadline.

Apply here: hr.umn.edu/jobs/Find-Job
Assistant Prof job code: 364920
Associate/Full Prof job code: 364921

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...

Thrilled that our paper is out today in Nature!
www.nature.com/articles/s4...

The mass firings have been lawless: now and all year The first step in stopping a lawless Supreme Court is being clear about what it’s doing

I wrote an explainer about the mass firings—the RIFs.

The RIFs all year have been clearly illegal. Russell Vought is using them to lawlessly clean out federal agencies. Lower court judges have said so. But the Calvinball Supreme Court has allowed them. 1/

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

Fisher meets Feynman: score-based variational inference with a product of experts

Fisher meets Feynman! 🤝

We use score matching and a trick from quantum field theory to make a product-of-experts family both expressive and efficient for variational inference.

To appear as a spotlight @ NeurIPS 2025.
#NeurIPS2025 (link below)

Want the freedom of a fancy fellowship, but not the year-long wait or arduous application?

Come join my lab! Work on neuroscience and AI, explore your creativity, be independent or work closely with me, collaborate widely, and have a lot of fun!

my.corehr.com/pls/uoxrecru...

Hotter take: We should only be reporting nonasymptotic confidence intervals using empirical Bernstein inequality or something similar.

Dividing by sqrt(n) is incorrect unless n = infinity.

(To be clear, I am 100% trolling)

Looking for a PhD program where you can study computational neuroscience? NYU has a fantastic array of researchers covering the field:

groups.google.com/g/systems-ne...

Burning out The international AI industry's collective risk.

A new essay on the crazy, all or nothing approach to work happening in AI today, the looming human costs, and the lack of a finish line.

I wouldn't say it's okay, but I'm not sure how to fix it.
www.interconnects.ai/p/burning-out

Single-unit activations confer inductive biases for emergent circuit solutions to cognitive tasks - Nature Machine Intelligence Recurrent neural networks are widely used to model brain dynamics. Tolmachev and Engel show that single-unit activation functions influence task solutions that emerge in trained networks, raising the ...

Excited to share our new work with @engeltatiana.bsky.social!

RNNs are often used to explore how the brain may solve specific tasks. We show that, depending on the architecture, RNNs find distinct circuit solutions, behaving differently when exposed to novel stimuli.
www.nature.com/articles/s42...

The NIH institute director firing last Friday is very bad.

I made a video explainer about why.

Stay for last post, w link to @science.org story from @jocelynkaiser.bsky.social

1/4
🧪

🧠🌟🐭 Excited to share some of my postdoc work on the evolution of dexterity!

We compared deer mice evolved in forest vs prairie habitats. We found that forest mice have:
(1) more corticospinal neurons (CSNs)
(2) better hand dexterity
(3) more dexterous climbing, which is linked to CSN number🧵

Delighted to share our new paper, now out in PNAS! www.pnas.org/doi/10.1073/...

"Hierarchical dynamic coding coordinates speech comprehension in the brain"

with dream team @alecmarantz.bsky.social, @davidpoeppel.bsky.social, @jeanremiking.bsky.social

Summary 👇

1/8

The spatiotemporal structure of neural activity in motor cortex during reaching Intracortical brain-computer interfaces (BCI) leverage knowledge about neural representations to translate movement-related neural activity into actions. BCI implants have targeted broad cortical regi...

🚨Pre-print alert! 🚨https://www.biorxiv.org/content/10.1101/2025.10.17.683171v1

Our new study tackles the question: do all neurons in motor cortices (MC) encode movement & coordinate as we move? Answering this question will be key for effectively targeting motor representations in BCIs.

Today in Nature Machine Intelligence, Kazuki Irie & I discuss 4 classic challenges for neural nets — systematic generalization, catastrophic forgetting, few-shot learning, & reasoning. We argue there is a unifying fix: the right incentives & practice. rdcu.be/eLRmg