Two parallel neural ectoderm progenitors contribute to the developing brain

Two parallel neural ectoderm progenitors contribute to the developing brain med.stanford.edu

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664 points•emigre•12 days ago•258 comments•

#x2f #brain #parallel #ectoderm #neural #developing #progenitors #contribute

https://www.nature.com/articles/s41593-026-02433-7

258 comments

ksenzee12 days ago

The really exciting thing in this article is that this research led them to a new technique for growing brain stem cells in vitro, which has been very difficult until now. If that isn't being oversold, it's big news. That's going to make future research into diseases like ALS a lot easier.

computerdork11 days ago

Agreed. This isn't being oversold.

And actually, the fact that the brain is actually two "developmental" systems combined into one seems like big news to me. We might not know its other uses, but probably for cognitive science and even AI research this might be super useful. In AI, maybe two models should be developed and trained in conjunction that talk to each other, each with different functions and roles, because brains work better this way.

And from what I read, evolution did this type of combined evolution somewhat often. The parts of the ear evolved from different "Gill slits" from when we were fish, meaning the ear isn't evolved from one group of cells in the embryo, but from multiple groups of cells that evolved into one organ system, the ear. Yeah, the middle ear evolved from a different "gill slit" from the outer and inner ear.

ACCount3911 days ago

"The brain does it" is not in itself a reason to do the same in AI.

Sometimes, what the brain does is genuinely a good solution to a given task - one that's good regardless of whether your neural network is of artificial or biological variety. But sometimes, what the brain does is an evolutionary kludge, or a hack that works around one of the "being made of flesh" issues - of which there are a great many.

We have known examples of both - and a few known features that might go either way.

The brain does have some known useful features that we are yet to plunder - usually because we know they're there somewhere but not how they work. We don't know how the brain stabilizes online learning, for example. Or what low k-complexity priors and data augmentation processes does it use to enable its sample efficiency.

But a two-system split? Useless by itself. Splitting a network in two is easy - but if we don't know what that split does, what it buys us, what useful bias does it impart? We're just adding complexity. See: the investigation into HRMs, and how the "hierarchical" part proved to be a lot less meaningful than anticipated.

eli_gottlieb11 days ago

> And actually, the fact that the brain is actually two "developmental" systems combined into one seems like big news to me.

It was known and discussed in evolutionary-developmental neuroscience, but not much outside that.

LordDragonfang11 days ago

> maybe two models should be developed and trained in conjunction that talk to each other, each with different functions and roles, because brains work better this way.

I mean, is that not essentially what a Mixture of Experts model is?

pseudohadamard11 days ago

Not sure why this is such big news, it's been known for centuries that guys have two brains, and often do the thinking with the little one.

shwaj11 days ago

The article didn’t make it clear: the breakthrough is the discovery of a new third brain, beyond the two previously known.

goosejuice11 days ago

Which one contains the soul?

computerdork11 days ago

Umm, as a man myself, I've got to say that I am always well behaved and have never gratified my sexual needs, ever! Sheesh, you neanderthal (haha:)

Alien1Being11 days ago

The actual research says something far less clickworthy. Are Stanford's PR dribbles now created by LLMs ?

"Two parallel neural ectoderm progenitors contribute to the developing brain

Abstract When and how different brain regions diversify from one another remains unresolved.

Does a common neural ectoderm progenitor generate the entire brain? Or do multiple neural ectoderm progenitors exist, each restricted to form specific brain regions?

Here our lineage tracing studies of mouse embryos support the latter model. Two parallel brain progenitors emerge simultaneously during gastrulation: anterior neural ectoderm (forebrain/midbrain progenitor) and posterior neural ectoderm (hindbrain progenitor). Differentiation of human pluripotent stem cells into anterior or posterior neural ectoderm-like cells revealed these were lineage committed to forebrain/midbrain versus hindbrain fates, respectively. They harbored diverging chromatin landscapes foreshadowing future forebrain/midbrain versus hindbrain identities. We further differentiated human pluripotent stem cells into hindbrain rhombomere 5/6-specific motor neurons, which were hitherto difficult to generate in vitro.

Hence, we postulate the brain is a composite organ emanating from two lineage-restricted progenitors; these dual progenitors may be evolutionarily conserved across 550 million years from hemichordates to mammals."

itsalwaysgood11 days ago

I think it's very interesting news. We've known about the brain's separate parts, and separate functions for a while. It was always assumed our evolution of the brain was neatly, and tidily tucked away as somethat that branches off a singular thing. A single step from the pluripotent, 'infinitely renewable' stem cell into another single progenitor.

This suggested a sequence of events, causes and effects, that somehow our minds today can be evolved from a singular 'step' within growth. Only our brains seems have this requirement.

So this requirement, in and of itself, is interesting and newsworthy. For whatever purposes, it's 2 separate systems that many living organisms evolve in the same way. It's 2 steps, for some physical reason.

k31012 days ago

bioRxiv preprint July 2025 [0]

The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY 4.0 International license.

[0] https://www.biorxiv.org/content/10.1101/2025.07.02.662771v2

PDF is free to download.

Perenti12 days ago

All the comments I see are about is it two organs, or a composite organ.

Surely the interesting thing is the ability to grow hindbrain cells in vitreo. That's what's potentially going to lead to the cure of lots of things, not whether 1=2.

burnte11 days ago

Both are fascinating. I've had a pet theory for 30 years that there is not a single "mind" but that we're made up of more isolated aspects that do different things and working in concert we come up with our idea of "a mind".

heddhunter11 days ago

Have you ever done any mindfulness meditation? I hit on a similar idea while meditating. My analogy is the brain is like the full spectrum of radio frequencies, but there's a "main station" that is "I". From time to time you lose that signal and tune into something else. And just because you're not listening to it, it doesn't mean the other stations aren't still broadcasting.

I have no idea if there's a biological origin for any of this, but it definitely fits with my experience of meditation and awareness training.

jabagawee12 days ago

> The new research finding shows that the human brain consists of two ancient nervous systems cleverly packaged together — a more primitive part that regulates our hearts’ beating, our breathing and other functions, and another that makes us distinctly human, capable of poetry, mathematics and wondering about our own origins.

I'm not sure the actual article in Nature Neuroscience [1] actually says that. I remember "Your Brain Is Not an Onion With a Tiny Reptile Inside" [2] from a few years ago, but I'm not sure where the dissonance comes from: my own misunderstanding, the press release using a popular but flawed model to communicate with laymen, or these two articles being in direct contradiction with each other?

[1]: https://www.nature.com/articles/s41593-026-02433-7 [2]: https://journals.sagepub.com/doi/10.1177/0963721420917687

zargon12 days ago

"Your Brain Is Not an Onion With a Tiny Reptile Inside" is a really stupid and pretentious article arguing against a straw man.

computerdork11 days ago

Interesting, but for me at least, this new research did not seem to promote the dispelled hypothesis about the reptile brain. Because the reptile brain hypothesis says a primitive reptile-brain evolved first (lower brain), then a separate part of the brain (upper brain) evolved later that was responsible for complex thought.

Actually, the upper and lower brains evolved together and most animals have both, including reptiles.

Didn't read it thoroughly, but your [2] reference seems to be saying this too.

dr_dshiv12 days ago

[2] is an annoying pedantic article that illustrates little beyond a misconception of a misconception.

Read the full thread on Hacker News →

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