Stanford Medicine discovers the human brain is actually two separate organs
Human brain is two separate organs, Stanford Medicine-led research finds
Stanford Medicine researchers found that the forebrain and hindbrain arise from two distinct progenitor cells that never overlap, overturning the long-held single-origin model. The discovery explains why growing hindbrain neurons in the lab failed for decades and opens new ways to study ALS, SMA, and other brain stem diseases. The same two-origin pattern appears in chickens, zebrafish, and acorn worms, suggesting an ancient evolutionary split.
We’ve shown for the first time that the front of the brain arises from a totally different progenitor cell than the back of the brain.
- itvision
What a way to oversell the discovery.
The reality is:
* Different brain regions have different functions: ancient knowledge.
* Different regions contain distinct cell types and molecular programs: also well established.
* Anterior and posterior brain structures may trace back to fundamentally separate progenitor lineages that were independently specified very early in evolution and development: that's the interesting new result.
The headline should have been: "Human forebrain and hindbrain arise from distinct embryonic progenitor lineages" - not that we have "two organs" in the brain.
- bethekind
> They identified two different brain progenitor cells. One, which expresses a gene called Otx2, is destined to become the forebrain and midbrain. The other, which expresses a gene called Gbx2, is committed to forming the hindbrain. They showed that these two cell populations never overlap; they are mutually exclusive from the earliest stages of development.
Very cool. Never thought the brain could have two completely different ancestors
- ksenzee
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.
- enjrolas
I feel like, even though they got this knowledge, any researcher at any time could have grown hindbrain cells from pluripotent stem cells -- the resulting practice didn't _require_ the understanding.
I also don't get why they needed a pluripotent stem cell and not, say, another hindbrain neuron. I get the claim that you can't get forebrain neurons to act like hindbrain neurons, but is it possible that every previous researcher who was trying to grow hindbrain neurons in vitro was starting with forebrain neurons?
- k310
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.
- msephton
Related https://www.newscientist.com/article/2589739-our-brain-evolv... https://news.ycombinator.com/item?id=49755533
- meindnoch
Fun fact: 80% of the brain's neurons are in the cerebellum, not the cortex.
In other words: only <20% of pur neuron budget goes to higher cognition (thinking, language, seeing, hearing). 80% is spent on motor skills.
- jabagawee
> 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