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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
"Nervous systems are typically defined as networks of neurons that communicate across synapses. But Burkhardt’s lab found something unique in ctenophores: Beneath the animal’s outer surface is a nerve net (pink mesh in this 3D reconstruction) whose neurons are connected by continuous cytoplasm — but with no synapses between them. “I don’t think any other animal has a nervous system like that,” Burkhardt said. Because ctenophores are one of the earliest branches of the animal family tree, the finding indicates that evolution may have crafted nervous systems twice: in ctenophores, and separately in jellyfish and all other animals."
Like the thought:) But actually have read that the hypothesis that the hindbrain (or lower brain) had evolved directly from our lizard ancestors while the upper brain (which does more complex types of thought) evolved later turned out to be wrong. Like the study has shown, they evolved at the same time, and many animals had both. It's just in humans, the upper brain evolved much larger in proportion to the lower brain.
I think there is a better way: The colder something is, the less sweet it will taste. if you warm-up ice cream and taste how sickeningly sweet that soup is, you won't be having so much for a while...
Also, doing high-effort endurance exercise for long enough suppresses grelin production (the hunger hormone). I've seen 30+ minutes of running or 60+ minutes of cycling as the most common rules of thumb.
So in order to stack all these effects to maximum effect: plan exercise before meal, plan mean before doing groceries.
I think that adipose tissue is the biggest criminal when it comes to unwanted hunger, since it produces hormones to make you hungry the moment you actually risk losing weight.
Not sure how much the digestive neurons are involved with hunger actually, I thought its role was more about telling you which foods make you nauseous so you won't eat them, or subconsciously register which nutrients various foods have so you'ld crave the ones compensating for shortages more.
I heard adipose tissue also retains hormones and fat-soluble pollutants, and losing weight releases them and they have to be dealt with by the body in other ways. Specifically, the hormones can cause mood swings, which some individuals have learned to react to with binge eating.
The peer reviewed publication is linked to from the press release. The press release's headline does somewhat overhype up the actual finding though. The actual finding is that different parts of the brain arise from different neural ectoderm progenitors, which explains why it’s so hard to get a forebrain neuron to behave like a hindbrain neuron and vice versa in the lab. The paper then postulates that this difference in progenitors resembles being two different organs evolutionarily, but this is not really the most important part of the paper.
BTW I suspect that this finding comes as completely unsurprising to biologists and the medical field generally. I'm not in either field, but even in high school biology we learned that the brain stem is behaviorally and structurally radically different from the rest of the brain, to the point where it seems almost obvious in hindsight that it's a different cell line and potentially has a different evolutionary history from the rest of the brain.
* 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.
Lying is always a bad choice. The paper in Nature says
"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."
I think "Human brain evolved from two separate organs" would've been more accurate and sufficiently simple/short for a headline, but I guess it won't fly either due to political reasons.
I think "Human brain evolved from two separate organs" would've been more accurate and sufficiently simple/short for a headline, but I guess it won't fly either due to political reasons.
I don't agree. For that you need to distort the definition of what an organ is to comply the requirement for two separate organs with distinct origin, genetic, and biochemical traits, and different function and responsibilities to somehow remain classified as the same organ.
Given the parallel example cited in the article of jellyfish having two spatially separate organs, & the subsequent speculation that our own ancestors could also have had spacially separate anterior & posterior masses, the title doesn't really seem unreasonable in its hyperbole.
While it might not be perfectly accurate it's hardly misleading.
I found the title confusing, at the very least because it can be argued that the two brain hemispheres are two organs already, as they operate independently when severed from each other.
This is not a good analogy, because both kidneys do the same thing and we don't need both of them to live.
Whereas the left and right brain hemispheres do different things that enable our species to be what it now is; which is more similar to what the article calls hind and fore/front brains, which again do different things that we wouldn't be us without. We would still be human if we had only one kidney the way we have only one bladder or one pancreas.
Kidneys are more like say lungs, gonads, breasts, or nostrils in that we have +1 extra; but the benefit created by multiplicity is ~doubling or capacity and resilience to local disease and random injury-- not a profound functionality. (Like is created by the second eye or second leg.) Of these, the second breast is radically more useful than the second kidney, and is probably a special case as it changes how we live so evolved.
The right and left hemispheres do different things… unless you had a hemispherectomy as an infant and then one half is able to mostly perform the duties of both.
I wonder if we would have been capable of endurance hunting without both lungs. I suspect that changing that would have very drastically changed human development.
Possibly, but I wouldn't assume any connection. In sociological terms, modern universities are mid-last-millennium noble houses*, locked in an endless competition for power, wealth, prestige, and influence. Adding a few stanzas of hyperbole when bragging about one of their knights vanquishing some infidel of ignorance? That's simply how things are done.
*Yes, there's never really a king or duke or whatever. But consider the history of the word regent.
"Human forebrain and hindbrain arise from distinct embryonic progenitor lineages"
I'd have never clicked that headline nor understood why this finding is important.
If you think the original headline is not "truthful" enough, at least do something like "Researchers found the reason why hindbrain cells cannot be grown in a lab and found a way to overcome it"
not that we have "two organs" in the brain.
Depends what the definition of "organ" actually is. What speaks for different organs here is that the cells both have a different pathway from stem cells and have different evolutionary histories. That is different from other brain regions that may have separate functions but still evolved together.
I think it's less about what was said (it is truthful) and more what isn't mentioned in the title which leaves ambiguity.
I don't necessarily think it's intentional. For those with knowledge in the field I suspect it resonates the appropriate reaction.
For those outside of the field, I think the perception of what being 2 organs means does a lot of leg work in invoking a response which seems exaggerated, but is probably caused by incorrect assumptions of what the title is trying to convey.
I hope that makes some sense, I feel that was a lot of word vomit but I'm struggling to find the right words, it's somewhat meta
You stated that the current headline informs you why the result is important. Why is that? Surely, given that the information was communicated to you, you can share it with me?
We should not be wary of loud truths either. Unless we push the envelope we cannot trace back to the essence. Like, as an outsider in this discussion, I am now inclined not only to assess the finding, but also the definition of an organ. The title did good work. Its refutation too. Fencing every statement in unquestionable truth does not make the pursuit of truth stronger.
But there’s rarely one correct answer. Conveying the same approximate message to multiple types of readers is extremely difficult in a handful of words. People with subject matter knowledge are annoyed by headlines written for laypeople that don’t know the jargon or have a mental model of the important concepts that jargon represents. They always seem to miss important distinctions, make poor analogies, or the like. Headline-length blurbs that successfully convey those things to the knowledgeable are often utterly opaque to laypeople causing them to ignore articles about topics they’d find interesting. The only option is trying to estimate the subject matter expertise of the audience, and despite many people in the tech world assuming their software knowledge gives them technical expertise in many non-software fields, the layperson headline is absolutely the best approach here.
This is not true. There is a complex relationship between truth and good communication. The relationship is non linear and convoluted and it depends often on the subject of what is being communicated.
There are many many cases where lies are easier to communicate than the truth.
Take tobacco for instance. For the longest time we did not know it was bad for you. It took decades of epidemiological research and statistical techniques to ascertain that it was bad.
The truth was buried in numbers and human knowledge about applied mathematics and statistics. Without centuries of human endeavor to create the concept of science unionized with the rigor of statistics the truth would have remained forever invisible.
The sheer complexity of the truth in this case makes is extremely hard to communicate. We mostly trust that smoking is bad based off of the reputation of the researchers who established that fact. But the truth was never really directly communicated to most of us as it involves diving deep into the data.
The truth about tobacco was known for years but ignored because 1) industry lobbying and 2) the Nazis were the ones who figured it out, and pushed anti-smoking hard, so smoking became something "our side" did, 3) tobacco was still a huge US export.
It was easy to communicate, but we were motivated to not listen.
No the deaths were buried deep in the statistical data. It’s not apparent and we did not know either way.
Yes there were people who said it’s bad but their word was as good as bullshit because until we had the statistics there is literally no way to truly know.
No, the Germans had good statistical data linking smoking (as well as asbestos and other carcinogens) to cancer by the 1930s; this was known and ignored (or actively derided) by the allies. It's one of the classic and well known examples of ad hominem.
There is a complex relationship between truth and *good* communication. [...] There are many many cases where lies are *easier to communicate* than the truth.
You're literally conflating good communication with easy communication.
Armed with this knowledge, the researchers for the first time successfully coaxed human pluripotent stem cells (a kind of cell that can create any cell in the human body) to become functional hindbrain motor neurons in the laboratory.
...
The research also has implications for investigating treatments for SMA, ALS and other conditions affecting the brain stem. Until now, studying these diseases has been nearly impossible because scientists cannot obtain brain stem tissue from living patients. The ability to grow these neurons in a dish opens new possibilities for understanding what goes wrong.
But no, nothing to see here, not worth our time for this overblown article apparently ...
I don't have a problem with the 'two organs making one' framing. The fact that they are 'symbiotic' now doesn't change that. In fact it helps me understand two key facts. One can't grow out of the other, and they work differently. Great
The Portuguese Man o’ War[0] is a symbiotic organism. If you want to get technical, I guess we are, as well. We’re really kind of fascinating meatbags.
We are absolutely symbiotic from our cells upward. A large percentage of your body mass is bacteria, including the symbiotic bacteria you feed in your gut with the food you think you’re eating only for yourself.
Main issue I have with the title is it immediately reminded me about McGilchrist's "The Divided Brain" and I thought they meant the two halves - but that is not the case.
This is meaningless semantic drama over a meaningful discovery. From a biological and medical perspective, the collective term "organ" is pretty useless, if there is a distinct progenitor lineage. For the sake of a simplified explanation for the public, describing this discovery as finding "two organs" is absolutely fair.
A similar example: The melanocytes in the skin originate from the neural crest, not the epidermis. As a significant consequence, melanocytes share cell attributes with neurons. One of these attributes is the ability to infiltrate other tissues. Because of that, malignant transformation of melanocytes has vastly different consequences, compared to epithelial cells. If you asked your doctor why squamous cell cancer and melanoma have such different prognoses, describing your skin as effectively "two organs" would be illustrative and easy to understand, without getting into developmental biology.
I think you're right. And I would even assume that, should the article be from Fox News (just an example), every other commenter that excuses the title would have yelled at journalism slop, clickbait and whatnot.
But that's stanford.edu, so we must tread lightly.
I've found it useful to think in terms of how such structures might have evolved. The beginning state is always something very simple: the first nerve. It must go from A to B. Perhaps from a food sensing area to a muscle. Sense food, stop moving, something like that. Organisms could evolve multiple copies of that structure: N nerves going from A(n) to B(n). At some point the next invention arises: some logic gate type thing that branches and/or combines nerves. So now sensing food can make movement stop and also digestion begin. Or food response can be attenuated during the day time. And so on. There's no reason why you'd have exactly one of these "nerve processor" nodes. There's also no reason why several different kinds of them and different instances might evolve. They're useful. Then at some point the next discovery is made: by combining several nerve processor nodes in close proximity, with their own inter-node connections, you can perform more complex processing. You've now got a proto-brain. But again there's nothing to say you have exactly one of these things, or that they're exact replicas of each other.
I'm sorry, it just sounds like you're mad at medical researcher for trying to make their research more accessible?
What do you mean by oversell? And why do you think the general public would be more apt to understand "distinct embryonic progenitor lineages" than "two organs"?
What exactly is the problem here? You think medical researcher are using medial nomenclature wrong?
Agreed. Anybody who looks at a picture of the brain can see the cerebellum (part of the hindbrain) is obviously a different organ. I only clicked the link to find out if there was any new science buried under the hype of the title.
They also use this result to great hindbrain neurons in the lab for the first time, so it's a strikingly useful discovery.
I think it's also fair to say they are different organs based on the developmental physiology. Many other organs come from distinct embryonic cell lines.
When an organ is known to be generated from 2 distinct embryonic preforms, which become merged and integrated at a later stage of development, there is a likelihood that in some distant ancestor the integration into a single organ was much less advanced than now and possibly the two parts remained as relatively separated organs even during adulthood.
There are many groups of animals that include both some species that have retained a more primitive condition, where some nervous ganglia have remained separated, while other species have a derived condition, where those nervous ganglia have fused into a single ganglion.
In this case it is not known for sure what happened, because the early evolution of the nervous system, from a sensory structure embedded in the skin to a complex internal system that mediates the communication between sensors and motor or secretory organs, is still poorly understood.
In any case, this research confirms that the differences between forebrain+midbrain (which includes the cerebrum) and hindbrain (which includes the cerebellum) are very important, because they become established very early during the development of the embryo, at a time when the progenitors of many organs are still interchangeable.
Yeah, this is a frequent failure of science communication. Misleading clickbait overselling a paper that made real progress in some capacity. I'd be more interested in hearing the truth of the matter and about the researchers passion for their study area. Spinning everything into some high stakes breakthrough that fundamentally changes our understanding of the world just makes me feel like my time was maliciously wasted and that I shouldn't click on news about science.
can confirm from experience that the headline and press release were likely 100% from Stanford’s comms department and the authors are likely panicking about the hyperbolic spin
When I studied neuroanatomy in the early 2000s it was already taught that the evolutionary history of the forebrain (from comparative anatomy) seems to have invaded the hindbrain and seems to control it like a puppet. It's nice to see this sort of confirmation but it doesn't strike me as an earth-shaking discovery except that it might give some insights for differential drug targeting.
This is one of the problems with modern academics, every paper has to be framed as some revolutionary idea or insight. We should celebrate “boring” research that serves nothing other than curiosity.
Academics themselves rarely frame their research in sensational terms. This happens in press releases and media coverage, which they have little control over. You can see this by comparing the title of the press release to the quotes by the actual researchers:
"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."
"I was surprised at our findings because the word ‘brain’ implies a contiguous organ that likely has a singular origin," Jokhai said. "But even 500 million years ago, there were these separate neural systems, which now almost operate as one, which is very cool."
I don't hear much overselling or hype in this, I hear an accurate description of the research and a bit of nerding out over it.
It's the same problem as when a journalist or nonfiction author writes a thoughtful, nuanced piece of work, and some editor slaps a catchy title and subtitle on.
A physical connection and collaborative function aren't enough to define a single organ anymore. It must also share a developmental and evolutionary origin.
The audience for a news headline is a layperson who may have no knowledge of or context to infer past factoids about brain regions or evolutionary biology.
There’s a balance between being informative to the audience and satisfying for pedants.
It's cool, but the headline is really pretty misleading.
The new result seems to be that researchers have identified different progenitors for fore/midbrain vs. hindbrain and have found that they can be identified by some specific developmental gene markers. That's genuinely cool.
However, organs are not typically defined by a single tissue characterized by a progenitor that can be labeled with a single gene marker. I suppose it's fine if on a functional and anatomical level you want to split the fore/midbrain and hindbrain into two different "organs", but whether you think of the brain as 1 organ or 2, it really doesn't change much in terms of how you would think about these regions.
It isn't at all surprising that different regions of the brain have localized functions; some of the earliest evidence of this was how focal injuries (like strokes) have characteristic deficit patterns depending on brain region affected, and obviously there has been a lot of work since then further showing the organization, function and development of different brain regions.
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.
It really fascinates me how dumb HN community is considering they know nothing about brain on the level of actual experts yet readily comment it as “non important” based on vibes.
If this is not your area of expertise why comment with stunning confidence on something you have no idea about?
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.
Title: "Two parallel neural ectoderm progenitors contribute to the developing brain".
"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."
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?
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.
What is the difference between saying that the brain is two organs, as in the title, or a "composite organ" as in the actual paper? What makes an organ a single autonomous organ?
The digestive tract could also be seen as a single organ since they are connected. I think the deciding criteria should be the one applied in this study, i.e., how an organ develops.
The cerebellum isn't just for motor skills. It's more of a place where very commonly used patterns get a bunch of dedicated wetware so the computation is superfast and precise. In an (undoubtedly very limited) analogy a bunch of FPGAs to complement the general processing. It does make a lot of sense to use this functionality for motor skills, though.
It's spent on 'fast, effortless' recall. Maybe, long-term memory, or memories associated with activities like balance, singing, and anything that requires precise steady control.
A keeper of balance and rhythm, if you want to think of it that way, and anything that is too much of a burden to creativity: a mind is a bunch of ideas (thoughts) collected into a moment in the mind, all the ones needed for controlling things like balance and rhythm are best handled in an autonomously looped fashion (think Cybernetics: control loops that guide an agent).
The article mentions the forebrain controls creativity, reasoning, higher-level thinking. And the hindbrain controls muscles of the throat, tongue, etc: so speech, singing. We all reach for some 'flow' state: perhaps it's this state where the 80% and 20% are more in harmony within the mind. Where what we create with our minds is appreciated, and the outer loop that critiques ourselves lays quiet. 'Flow' is achieved.
Everything becomes an autonomous loop: which is the study of Cybernetics, and (coincidentally?) the birthplace of AI.
If we follow the pattern of simulating biology, I would expect some ratio of compute could be determined 'optimal' for the new Dream-RSI technique recently: https://www.dream-rsi.com/ to eventually move towards '80%' of compute for autonomously controlled systems, and 20% towards 'something else'. The ratio won't be there in the beginning because an AI system has different autonomous needs.
Through testing and iteration, we'll arrive at some ratio as technology matures: my guess is it will match the one we find in our own heads: 80% for autonomous functions, 20% for creativity.
Keep in mind, dreaming and recursive self-improvement as it is now, is a big unknown: nobody knows what ratio is best, but honestly it's less important because we're all looking at 'Quality' of results right now.
But as the technology matures and moves into robotics and more, and more complexity is required to 'do work': I expect 80% to be accurate.
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.
There is some truth (but not accuracy) to it, but not for this reason.
This article is about brainstem (aka hindbrain) vs the rest (midbrain + forebrain).
Evolutionally older animal lineages like fish, reptiles, birds all have midbrain + forebrain as well as the brainstem, so reptilian brain != brainstem.
Where there is some truth to our older "reptilian" brain is that the part of the forebrain called the pallium, that exists even in fish (& reptiles), has much expanded/evolved in mammals giving us our cortex and hippocampus, so you could kinda say that we have a reptilian brain + cortex. Note though that mammals didn't evolve from reptiles - they evolved in parallel from a common ancestor, so maybe better to say we have a fish brain + cortex (& hippocampus).
While the cortex is what gives mammals their intelligence, in birds the pallium evolved in a different way to give them theirs.
am no expert in brain development, still have read about evolution. I like aspects of the way you mentioned this, but seems that putting cortex separately from fish brain isn't quite right. As you mentioned, the cortex is simply a part of the fish brain that evolved much (much, much) larger than a fish's. Maybe:
Fish Brain = brain stem + small cortex (+ other parts of brain)
|
(evolved into)
|
V
Human Brain = brain stem + gigantic cortex (+ other parts of brain)
Sorry, know this is splitting hairs, but just thought it a useful distinction to make.
That's not quite right - a fish does not have a cortex.
The pallium of a fish and mammal are structured differently. A fish's (& bird's) pallium has a clustered (aka "nuclear") organization, while a mammal's has a mostly layered organization which is what is referred to as the cortex.
There is also more to a brain than just brainstem + pallium. In a vertebrate it's brainstem (aka hindbrain) + midbrain + forebrain, with the pallium being part of the forebrain.
I don’t think the medical community has believed as the article claims for nearly a century.
Most animal brains have three very different organs in the brain: the cerebrum, cerebellum, and the limbic system (which itself is further divided into numerous differentiated types of tissues)
that's funny when I was in junior school, 15 years ago, I said in the classroom during science class, that we have 2 brains. everyone including my teacher were laughed at me.
There's a very interesting split-brain experiment [1] and Joe Scott's video about it [2]
TL;DW: Doctors treated corpus callosotomy by severing the bundle of nerve fibers that connect hemispheres of the brain. The surgery effectively stopped seizures from spreading. Left hemisphere handles language, speech, and logical interpretation, right hemisphere handles visual, spatial, and literal tasks.
Because human eyes send visual information to opposite sides of the brain, researchers could show images only to the non-speaking right brain. The right brain could see and physically react to the image (like picking up a matching object with the left hand), but the patient couldn't verbally explain what they were seeing because the left brain was literally in the dark. Instead of saying "I don't know," the speaking left brain would instantly and confidently invent a logical—but completely fake—justification for the action.
I worked with a doctor once to build a 3D Model of the brain apertures.
Disclaimer: the work presents these as spiritual/meditational reference points, not established neuroanatomical structures.
Textual reconstruction of the “Brain Apertures” diagram used in the Radhasoami/Surat Shabd Yoga tradition. The named “apertures” are spiritual/meditational reference points in this tradition; labels such as temporal lobe, occipital lobe, cerebellum and brain stem are anatomical landmarks shown in the source diagram in the doc below.
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?
I wasn't expecting to get hit by AI generated slop on Standford's website. At least mark the article as being produced by AI.
“What they found was striking: … These differences essentially locked each progenitor cell into its respective fate, like travelers on parallel tracks that never cross.”
The dramatic colon, the obligatory closing metaphor, makes me ill.
I expected an article full of basic medical jargon: cerebrum, cerebellum, cortex, synapse, etc. Instead it's talking about "forebrain" and "hindbrain". This sounds remarkably unscientific.
Which is the one zombies hunger for and which is the one driving their unstoppable hunger? Maybe they just really miss having their brain whole again, and eating and walking is the only thing they know?
In short, no. The two types of thinking are both forebrain activity. One comes to a quick guess with pattern matching, the other goes slower with reasoning. It could be that some fast thinking is influenced by the hindbrain in some way, but the thoughts themselves are constructs in the conscious mind that inhabits the frontal lobes.
I learned of the Triune Brain through Carl Sagan's book The Dragons of Eden. It was an engaging, story-telling approach to a somewhat, in hindsight controversial concept. It sounds (oversimplified) like the paper the article describes here is an embryological validation of this model.
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."
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.
The brain is a composit of cells from two lineages that separate very early in development and reflect a deeper spatial and functional separation deep in the history of metazoan (read: animal) evolution.
Tying all this to humans specifically is just confusing. This is something that’s seen in a substantial portion of animals, and as such has nothing to do with “ poetry, mathematics and wondering about our own origins”. These features of humans evolved hundreds of millions of years after this two lineage composite organization of animal brains evolved.
I wish the article hadn’t gone out of its way in confusing these issues to push the “relevance” of the research. It’s a pretty remarkable finding anyway.
I've just being doing some googling to try to understand this research better.
It seems that it's been known for a while that more primitive animals have/had functionally distinct front (sensory) and rear (motor + autonomic) neural systems, with different genes (Otx, Gbx) associated with each. In 2003 it was shown that an extant species, acorn worms, have this front/sensory, rear/motor neural division, assumed to date back to the pre-chordates.
In vertebrates we also see this association of Otx gene expression in the mid/forebrain and Gbx in the hindbrain, but it had been assumed that these "two halves" of the brain had fused long ago... What this new research shows is that this fusion only happens during development of the embryo, which seems to be a fairly common phenomena "Ontogeny recapitulates phylogeny" whereby embryonic development follows the same steps as evolution (e.g. human embryo also has a tail, chicken embryo has teeth).
Of course the front/sensory and rear/motor neural systems aren't totally isolated, since the sensory signals serve to steer the motor programs running in the back, and our brain still follows this primitive division of functionality.
the forebrain, and hindbrain, dont merge during development, and they are not derived of radically different cells, and they originate from the same process. the difference between them is expressive regulation.
wikipedia being what it is, on par with secondary literature gives an overview of brain and nervous system origin.
the primary discipline is embryology, and if you view the progression from cellular to somatic, it is quite clear that structure of nervous system, and brain are early events during organogenesis, and are derived from contact and signalling between cellular plates. there is a gradient derived signal, that induces disparate potency of genetic expression. there is however, not , two individual centers of cellular genesis, all neural cells are derived from same cell cell interaction, and induced to take a constrained set of functionalities based on signal amplitudes.
the original research in question did not discover a two brain merger, thats a tragic misinterpretation that is doing disservice, and is not even the claim of the research.
the discovery is the difference in genetic expression that required a different cultural regime for hindbrain neurons invitro. previously the paradigm was that forebrain, and hindbrain required almost similar culture, and this discovery allows realization of that fact, leading to a cultural regime promoting invitro hindbrain neuroculture.
I wonder if there is a principle here we can apply to neural nets like dividing up the layers for different tasks (no not MoE but something more fundamental).
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.
Related https://www.newscientist.com/article/2589739-our-brain-evolv... https://news.ycombinator.com/item?id=49755533
Very cool. Never thought the brain could have two completely different ancestors
and from another post on the front page right now https://news.ycombinator.com/item?id=49735541 :
"Nervous systems are typically defined as networks of neurons that communicate across synapses. But Burkhardt’s lab found something unique in ctenophores: Beneath the animal’s outer surface is a nerve net (pink mesh in this 3D reconstruction) whose neurons are connected by continuous cytoplasm — but with no synapses between them. “I don’t think any other animal has a nervous system like that,” Burkhardt said. Because ctenophores are one of the earliest branches of the animal family tree, the finding indicates that evolution may have crafted nervous systems twice: in ctenophores, and separately in jellyfish and all other animals."
Funny thing when reading that is as a human I read „crafted nervous system twice” like it would be done over a week or two.
We fail to imagine how much time takes to „craft a nervous system”.
Super scary how small are we in big scheme of things.
I think the fact that the sentence says we share the nervous system with jellyfish gives a good indication of that.
https://learn.genetics.utah.edu/content/senses/eye/
at one point I learned that it would only take a few hundred thousand years to evolve an eye, and time felt much deeper.
Fun fact: the hindbrain progenitor cell is shaped like a little lizard.
The lizard brain, not because it resembles the brain of a lizard, but because it's made up of a trillion tiny lizards
I bet you can tune hyperparameters on the MRI so that the resulting image makes the lizard brain look like a lizard, too.
Because they are proudly causing animalistic, degenerate behavior like Lizzo.
Like the thought:) But actually have read that the hypothesis that the hindbrain (or lower brain) had evolved directly from our lizard ancestors while the upper brain (which does more complex types of thought) evolved later turned out to be wrong. Like the study has shown, they evolved at the same time, and many animals had both. It's just in humans, the upper brain evolved much larger in proportion to the lower brain.
https://thebrainscientist.com/2018/04/11/you-dont-have-a-liz...
But yeah, evolution is fascinating.
Why would it be surprising?
All parts of the body are built like this. Otherwise we would be blobs.
Before becoming two parts they probably were part of the same parent protobrain tissue.
If you told me the hindbrain was ectoderm-derived but the forebrain was endoderm-derived, I might raise an eyebrow or two.
Please name one other organ that arises from two separate progenitor cell types. If this is common, I have never heard of it.
Well, your heart contains both mesoderm derived cells (enervation) and ectoderm derived cells (musculature).
Article says they weren't.
We are going to have to deprecate an idiom or two. "I'm in two minds about something" now gives the wrong meaning.
Not to mention the gut brain-- That's the organ I blame for the ice cream I just ate
The best way to stop eating ice cream is to stop buying ice cream. If it's in the freezer, it'll be eaten.
I think there is a better way: The colder something is, the less sweet it will taste. if you warm-up ice cream and taste how sickeningly sweet that soup is, you won't be having so much for a while...
The best ice cream I ever had was at a small shop in Athens that had unsweetened ice cream.
But how do you stop buying ice cream?
You buy your groceries while that piece of your brain has no excuse to make loud demands ;-)
Eat your dinner before going to the shop.
Also, doing high-effort endurance exercise for long enough suppresses grelin production (the hunger hormone). I've seen 30+ minutes of running or 60+ minutes of cycling as the most common rules of thumb.
So in order to stack all these effects to maximum effect: plan exercise before meal, plan mean before doing groceries.
Fill your freezer with frozen food other than ice cream.
I think that adipose tissue is the biggest criminal when it comes to unwanted hunger, since it produces hormones to make you hungry the moment you actually risk losing weight.
Not sure how much the digestive neurons are involved with hunger actually, I thought its role was more about telling you which foods make you nauseous so you won't eat them, or subconsciously register which nutrients various foods have so you'ld crave the ones compensating for shortages more.
I heard adipose tissue also retains hormones and fat-soluble pollutants, and losing weight releases them and they have to be dealt with by the body in other ways. Specifically, the hormones can cause mood swings, which some individuals have learned to react to with binge eating.
This isn't peer reviewed, just a press release. 10 other "papers" will be published in the next 2 weeks counterfinding anything in this post.
Science moves forward yet again with a few backward steps.
Here is the peer reviewed publication in Nature Neuroscience:
https://www.nature.com/articles/s41593-026-02433-7
The peer reviewed publication is linked to from the press release. The press release's headline does somewhat overhype up the actual finding though. The actual finding is that different parts of the brain arise from different neural ectoderm progenitors, which explains why it’s so hard to get a forebrain neuron to behave like a hindbrain neuron and vice versa in the lab. The paper then postulates that this difference in progenitors resembles being two different organs evolutionarily, but this is not really the most important part of the paper.
BTW I suspect that this finding comes as completely unsurprising to biologists and the medical field generally. I'm not in either field, but even in high school biology we learned that the brain stem is behaviorally and structurally radically different from the rest of the brain, to the point where it seems almost obvious in hindsight that it's a different cell line and potentially has a different evolutionary history from the rest of the brain.
I thought the PR article did a decent job or saying just that, except maybe for the title
Yeah, agreed. It's mostly just the title that is overhyped.
no idea what you're talking about.
watson and crick's paper was not peer reviewed, neither were darwin's papers.
not sure what you think happens in peer review but it's probably overrated.
The problem right now is that there aren't enough peer reviewers.
I don't think that's the problem.
One problem is that there's no good incentive to spend significant time doing good peer review.
Darwin submitted and presented his work to the Linnean Society of London — with papers by Darwin published by the society.
Darwin wrote his book Origin of Species the following year.
I can see how one of these is the gut feelings origin, and other bodily feelings.
What a way to oversell the discovery.
The reality is:
The headline should have been: "Human forebrain and hindbrain arise from distinct embryonic progenitor lineages" - not that we have "two organs" in the brain.
I mean, I learned a bunch of neat new stuff, so I’m excited!
Though I agree with the detailed differentiation, still for the headline purpose a generic one that resonates with people easily isn't a bad choice
Lying is always a bad choice. The paper in Nature says
"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."
If they had written instead:
"Human brain was two separate organs"
Then, both attention grabbig and true?
Probably not, because by the time hominids were a thing, it was one.
(if I'm reading parent poster correctly)
Human Brain Evolved From Two Separate Organs.
Are there other composite organs?
Yes, but this is left for the next years because they give only one Nobel preis per year.
https://en.wikipedia.org/wiki/Siphonophore
That isn't even remotely related to the parent question. Organisms =/= Organs.
Do you think siphonophores don't have organs?
Does the adrenal gland count?
I think "Human brain evolved from two separate organs" would've been more accurate and sufficiently simple/short for a headline, but I guess it won't fly either due to political reasons.
But the evolution isn’t necessarily the important part, it’s the two parts having separate development processes in modern day humans that is notable.
You mean like, "assembled from two separate components"?
More like, they are two separate components, with some interwiring. Components, which we might also call organs. Two of them.
I don't agree. For that you need to distort the definition of what an organ is to comply the requirement for two separate organs with distinct origin, genetic, and biochemical traits, and different function and responsibilities to somehow remain classified as the same organ.
Given the parallel example cited in the article of jellyfish having two spatially separate organs, & the subsequent speculation that our own ancestors could also have had spacially separate anterior & posterior masses, the title doesn't really seem unreasonable in its hyperbole.
While it might not be perfectly accurate it's hardly misleading.
I found the title confusing, at the very least because it can be argued that the two brain hemispheres are two organs already, as they operate independently when severed from each other.
Totally valid point just as both kidneys are separate organs
This is not a good analogy, because both kidneys do the same thing and we don't need both of them to live.
Whereas the left and right brain hemispheres do different things that enable our species to be what it now is; which is more similar to what the article calls hind and fore/front brains, which again do different things that we wouldn't be us without. We would still be human if we had only one kidney the way we have only one bladder or one pancreas.
Kidneys are more like say lungs, gonads, breasts, or nostrils in that we have +1 extra; but the benefit created by multiplicity is ~doubling or capacity and resilience to local disease and random injury-- not a profound functionality. (Like is created by the second eye or second leg.) Of these, the second breast is radically more useful than the second kidney, and is probably a special case as it changes how we live so evolved.
The right and left hemispheres do different things… unless you had a hemispherectomy as an infant and then one half is able to mostly perform the duties of both.
TIL, gosh!
I wonder if we would have been capable of endurance hunting without both lungs. I suspect that changing that would have very drastically changed human development.
Additionally the only images in the linked article are also face pics of the researchers instead of anything on the information about said research.
I want to trust science and dislike anti vaxxers but it’s difficult to argue against them when researchers act like the caricature they are mocked as.
Self aggrandizing articles with misleading headlines is giving me 2 triggers for not trusting the content.
Wait, you think the article was written by the researchers?
You know, it's also difficult to trust someone's criticisms when they misassign responsibility. Just like anti-vaxxers do.
It’s the PR arm of a university, they always do this.
Pretty much, and they've less shame than a British tabloid in how far they go.
When submitting, one can try to replace the title with something honest. HN does not favor that, mostly due to submitters having their own biases.
The best tactic is finding a higher quality article on the subject, to submit instead. That's uncertain, takes time, and may run into paywall issues.
Possibly making matters worse, this is from Stanford where they had the university president caught engaging in fraud on Alzheimer’s research.
Possibly, but I wouldn't assume any connection. In sociological terms, modern universities are mid-last-millennium noble houses*, locked in an endless competition for power, wealth, prestige, and influence. Adding a few stanzas of hyperbole when bragging about one of their knights vanquishing some infidel of ignorance? That's simply how things are done.
*Yes, there's never really a king or duke or whatever. But consider the history of the word regent.
If the two parts arise independently, then the headline may be a bit clunky but it is technically correct.
I'm pretty sure the third thesis has been taught in my university physiology classes 20 years ago, too.
Oh, I think we could crank that headline even harder while still keeping one toe on the truth. For example:
"Elon Musk's Brain is Two Separate Organs"
Both of Taylor Swift's Brains are Over 500 Million Years Old
People with maternal Jewish DNA have two brains.
You'll be SHOCKED at what we found out about Taylor Swift's TWO BRAINS - that's flying much closer to the sun.
"and both are asbestos-free"
I'd have never clicked that headline nor understood why this finding is important.
If you think the original headline is not "truthful" enough, at least do something like "Researchers found the reason why hindbrain cells cannot be grown in a lab and found a way to overcome it"
Depends what the definition of "organ" actually is. What speaks for different organs here is that the cells both have a different pathway from stem cells and have different evolutionary histories. That is different from other brain regions that may have separate functions but still evolved together.
To me, this suddenly turned the discussion into a fascinating exploration and demonstration of different standards of truthfulness in marketing.
I still don't see how the original headline was not truthful.
It's as truthful and useful as "75.6% of humans who ingest oxygen end up dead".
That’s only wrong because it’s 100%.
Isn't it more like 93%? On the other 7% data is still inconclusive, they never died
Depends on if the study is ongoing
75.6% die is right, it's just that the other 24.4% do too.
Past results are not an indicator of future performance. YMMV.
I think it's less about what was said (it is truthful) and more what isn't mentioned in the title which leaves ambiguity.
I don't necessarily think it's intentional. For those with knowledge in the field I suspect it resonates the appropriate reaction.
For those outside of the field, I think the perception of what being 2 organs means does a lot of leg work in invoking a response which seems exaggerated, but is probably caused by incorrect assumptions of what the title is trying to convey.
I hope that makes some sense, I feel that was a lot of word vomit but I'm struggling to find the right words, it's somewhat meta
Why do you think it's important?
You don't think it's important?
You stated that the current headline informs you why the result is important. Why is that? Surely, given that the information was communicated to you, you can share it with me?
What I found important was this: "Researchers found the reason why hindbrain cells cannot be grown in a lab and found a way to overcome it"
But that finding is a direct consecutive of the "cerebellum is a different organ" finding from the headline.
In the context of a link aggregator, it’s arguably the only thing that matters
this is a great walk through the curiousity of the hindbrain: https://radiolab.org/podcast/song-of-the-cerebellum
The findings arn't exactly "new" but the medical science about it is definitely lagging current research.
Saying the truth and communicating well are orthogonal. You can do both.
We should not be wary of loud truths either. Unless we push the envelope we cannot trace back to the essence. Like, as an outsider in this discussion, I am now inclined not only to assess the finding, but also the definition of an organ. The title did good work. Its refutation too. Fencing every statement in unquestionable truth does not make the pursuit of truth stronger.
But there’s rarely one correct answer. Conveying the same approximate message to multiple types of readers is extremely difficult in a handful of words. People with subject matter knowledge are annoyed by headlines written for laypeople that don’t know the jargon or have a mental model of the important concepts that jargon represents. They always seem to miss important distinctions, make poor analogies, or the like. Headline-length blurbs that successfully convey those things to the knowledgeable are often utterly opaque to laypeople causing them to ignore articles about topics they’d find interesting. The only option is trying to estimate the subject matter expertise of the audience, and despite many people in the tech world assuming their software knowledge gives them technical expertise in many non-software fields, the layperson headline is absolutely the best approach here.
Not one bit of that justifies actively misleading people. Which is what that headline does.
This is not true. There is a complex relationship between truth and good communication. The relationship is non linear and convoluted and it depends often on the subject of what is being communicated.
There are many many cases where lies are easier to communicate than the truth.
Take tobacco for instance. For the longest time we did not know it was bad for you. It took decades of epidemiological research and statistical techniques to ascertain that it was bad.
The truth was buried in numbers and human knowledge about applied mathematics and statistics. Without centuries of human endeavor to create the concept of science unionized with the rigor of statistics the truth would have remained forever invisible.
The sheer complexity of the truth in this case makes is extremely hard to communicate. We mostly trust that smoking is bad based off of the reputation of the researchers who established that fact. But the truth was never really directly communicated to most of us as it involves diving deep into the data.
You understand what I did there?
Ah you told a lie. Demonstrating how easy it is to make it look true.
The truth about tobacco was known for years but ignored because 1) industry lobbying and 2) the Nazis were the ones who figured it out, and pushed anti-smoking hard, so smoking became something "our side" did, 3) tobacco was still a huge US export.
It was easy to communicate, but we were motivated to not listen.
No the deaths were buried deep in the statistical data. It’s not apparent and we did not know either way.
Yes there were people who said it’s bad but their word was as good as bullshit because until we had the statistics there is literally no way to truly know.
No, the Germans had good statistical data linking smoking (as well as asbestos and other carcinogens) to cancer by the 1930s; this was known and ignored (or actively derided) by the allies. It's one of the classic and well known examples of ad hominem.
You're literally conflating good communication with easy communication.
Easy communication correlates highly with good communication. It is easier to do good communication on easier topics.
“…but LLMs can’t” is the unspoken sticking point.
I actually saw the previous version yesterday and read it. Then I saw this one today and thought it was a different finding. Somewhat annoying.
Does this finding change your life in any meaningful way?
...
But no, nothing to see here, not worth our time for this overblown article apparently ...
I don't have a problem with the 'two organs making one' framing. The fact that they are 'symbiotic' now doesn't change that. In fact it helps me understand two key facts. One can't grow out of the other, and they work differently. Great
The Portuguese Man o’ War[0] is a symbiotic organism. If you want to get technical, I guess we are, as well. We’re really kind of fascinating meatbags.
[0] https://en.wikipedia.org/wiki/Portuguese_man_o%27_war
We are absolutely symbiotic from our cells upward. A large percentage of your body mass is bacteria, including the symbiotic bacteria you feed in your gut with the food you think you’re eating only for yourself.
Main issue I have with the title is it immediately reminded me about McGilchrist's "The Divided Brain" and I thought they meant the two halves - but that is not the case.
So the question still remains...
https://www.ted.com/talks/iain_mcgilchrist_the_divided_brain
This is meaningless semantic drama over a meaningful discovery. From a biological and medical perspective, the collective term "organ" is pretty useless, if there is a distinct progenitor lineage. For the sake of a simplified explanation for the public, describing this discovery as finding "two organs" is absolutely fair.
A similar example: The melanocytes in the skin originate from the neural crest, not the epidermis. As a significant consequence, melanocytes share cell attributes with neurons. One of these attributes is the ability to infiltrate other tissues. Because of that, malignant transformation of melanocytes has vastly different consequences, compared to epithelial cells. If you asked your doctor why squamous cell cancer and melanoma have such different prognoses, describing your skin as effectively "two organs" would be illustrative and easy to understand, without getting into developmental biology.
I think you're right. And I would even assume that, should the article be from Fox News (just an example), every other commenter that excuses the title would have yelled at journalism slop, clickbait and whatnot.
But that's stanford.edu, so we must tread lightly.
Agree on the ancient knowledge and some other interesting aspects I discovered when working with a Doctor who modeled 3D Brain apertures with me.
Comments somewhere down below has details.
No one will want to open your headline.
But third item means that there are two organs almost by definition, so original headline maybe slightly sensationalist, but not technically false.
I've found it useful to think in terms of how such structures might have evolved. The beginning state is always something very simple: the first nerve. It must go from A to B. Perhaps from a food sensing area to a muscle. Sense food, stop moving, something like that. Organisms could evolve multiple copies of that structure: N nerves going from A(n) to B(n). At some point the next invention arises: some logic gate type thing that branches and/or combines nerves. So now sensing food can make movement stop and also digestion begin. Or food response can be attenuated during the day time. And so on. There's no reason why you'd have exactly one of these "nerve processor" nodes. There's also no reason why several different kinds of them and different instances might evolve. They're useful. Then at some point the next discovery is made: by combining several nerve processor nodes in close proximity, with their own inter-node connections, you can perform more complex processing. You've now got a proto-brain. But again there's nothing to say you have exactly one of these things, or that they're exact replicas of each other.
I'm sorry, it just sounds like you're mad at medical researcher for trying to make their research more accessible?
What do you mean by oversell? And why do you think the general public would be more apt to understand "distinct embryonic progenitor lineages" than "two organs"?
What exactly is the problem here? You think medical researcher are using medial nomenclature wrong?
Honestly write a paper about it then.
I wanted a drawing, but was disappointed.
Agreed. Anybody who looks at a picture of the brain can see the cerebellum (part of the hindbrain) is obviously a different organ. I only clicked the link to find out if there was any new science buried under the hype of the title.
They also use this result to great hindbrain neurons in the lab for the first time, so it's a strikingly useful discovery.
I think it's also fair to say they are different organs based on the developmental physiology. Many other organs come from distinct embryonic cell lines.
Nonetheless, there is some truth in the headline.
When an organ is known to be generated from 2 distinct embryonic preforms, which become merged and integrated at a later stage of development, there is a likelihood that in some distant ancestor the integration into a single organ was much less advanced than now and possibly the two parts remained as relatively separated organs even during adulthood.
There are many groups of animals that include both some species that have retained a more primitive condition, where some nervous ganglia have remained separated, while other species have a derived condition, where those nervous ganglia have fused into a single ganglion.
In this case it is not known for sure what happened, because the early evolution of the nervous system, from a sensory structure embedded in the skin to a complex internal system that mediates the communication between sensors and motor or secretory organs, is still poorly understood.
In any case, this research confirms that the differences between forebrain+midbrain (which includes the cerebrum) and hindbrain (which includes the cerebellum) are very important, because they become established very early during the development of the embryo, at a time when the progenitors of many organs are still interchangeable.
Instead of starting a meaningless argument about the title, try reading the article. It explains the significance of this discovery.
we already knew the last part, they’ve just defined it a little better
Yeah, this is a frequent failure of science communication. Misleading clickbait overselling a paper that made real progress in some capacity. I'd be more interested in hearing the truth of the matter and about the researchers passion for their study area. Spinning everything into some high stakes breakthrough that fundamentally changes our understanding of the world just makes me feel like my time was maliciously wasted and that I shouldn't click on news about science.
Often the headline is not created by the author of the article.
Also newspaper headlines used to give a quick summary of the story, online articles as you say, clickbait.
can confirm from experience that the headline and press release were likely 100% from Stanford’s comms department and the authors are likely panicking about the hyperbolic spin
It's much simpler to change "is" to "was"
When I studied neuroanatomy in the early 2000s it was already taught that the evolutionary history of the forebrain (from comparative anatomy) seems to have invaded the hindbrain and seems to control it like a puppet. It's nice to see this sort of confirmation but it doesn't strike me as an earth-shaking discovery except that it might give some insights for differential drug targeting.
This is one of the problems with modern academics, every paper has to be framed as some revolutionary idea or insight. We should celebrate “boring” research that serves nothing other than curiosity.
Academics themselves rarely frame their research in sensational terms. This happens in press releases and media coverage, which they have little control over. You can see this by comparing the title of the press release to the quotes by the actual researchers:
"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."
"I was surprised at our findings because the word ‘brain’ implies a contiguous organ that likely has a singular origin," Jokhai said. "But even 500 million years ago, there were these separate neural systems, which now almost operate as one, which is very cool."
I don't hear much overselling or hype in this, I hear an accurate description of the research and a bit of nerding out over it.
It's the same problem as when a journalist or nonfiction author writes a thoughtful, nuanced piece of work, and some editor slaps a catchy title and subtitle on.
~ tHe gOd pArTiClE ~
A physical connection and collaborative function aren't enough to define a single organ anymore. It must also share a developmental and evolutionary origin.
The audience for a news headline is a layperson who may have no knowledge of or context to infer past factoids about brain regions or evolutionary biology.
There’s a balance between being informative to the audience and satisfying for pedants.
It's cool, but the headline is really pretty misleading.
The new result seems to be that researchers have identified different progenitors for fore/midbrain vs. hindbrain and have found that they can be identified by some specific developmental gene markers. That's genuinely cool.
However, organs are not typically defined by a single tissue characterized by a progenitor that can be labeled with a single gene marker. I suppose it's fine if on a functional and anatomical level you want to split the fore/midbrain and hindbrain into two different "organs", but whether you think of the brain as 1 organ or 2, it really doesn't change much in terms of how you would think about these regions.
It isn't at all surprising that different regions of the brain have localized functions; some of the earliest evidence of this was how focal injuries (like strokes) have characteristic deficit patterns depending on brain region affected, and obviously there has been a lot of work since then further showing the organization, function and development of different brain regions.
The impact is rather that is explains the failure of attempts to cultivate cell cultures of brainstem cells.
A bicameral mind cool
Actually, the mind should only exist in the forebrain:0
And that's why we oftentimes talk about "brains" in the plural
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.
It really fascinates me how dumb HN community is considering they know nothing about brain on the level of actual experts yet readily comment it as “non important” based on vibes.
If this is not your area of expertise why comment with stunning confidence on something you have no idea about?
Ego?
easy there:)
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.
The title is factually incorrect and is not what the research actually found:
https://www.nature.com/articles/s41593-026-02433-7
Title: "Two parallel neural ectoderm progenitors contribute to the developing brain".
"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."
I went to see Michael Gazzanigga talk about hemispheric separation some years ago. Fascinating. The two hemispheres can operate separately.
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
[2] is an annoying pedantic article that illustrates little beyond a misconception of a misconception.
"Your Brain Is Not an Onion With a Tiny Reptile Inside" is a really stupid and pretentious article arguing against a straw man.
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.
Wintermute and neuromancer!
What is the difference between saying that the brain is two organs, as in the title, or a "composite organ" as in the actual paper? What makes an organ a single autonomous organ?
The digestive tract could also be seen as a single organ since they are connected. I think the deciding criteria should be the one applied in this study, i.e., how an organ develops.
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.
The cerebellum isn't just for motor skills. It's more of a place where very commonly used patterns get a bunch of dedicated wetware so the computation is superfast and precise. In an (undoubtedly very limited) analogy a bunch of FPGAs to complement the general processing. It does make a lot of sense to use this functionality for motor skills, though.
See:
- https://pmc.ncbi.nlm.nih.gov/articles/PMC4089997/
- https://pubmed.ncbi.nlm.nih.gov/38663092/
So the 80% is spent on, more generally, habits and intuition. Makes sense.
Headline for IEEE: biologists show that human brain is basically a big FPGA devboard.
When cache is bigger than the database.
Well it's not bigger...
It's spent on 'fast, effortless' recall. Maybe, long-term memory, or memories associated with activities like balance, singing, and anything that requires precise steady control.
A keeper of balance and rhythm, if you want to think of it that way, and anything that is too much of a burden to creativity: a mind is a bunch of ideas (thoughts) collected into a moment in the mind, all the ones needed for controlling things like balance and rhythm are best handled in an autonomously looped fashion (think Cybernetics: control loops that guide an agent).
The article mentions the forebrain controls creativity, reasoning, higher-level thinking. And the hindbrain controls muscles of the throat, tongue, etc: so speech, singing. We all reach for some 'flow' state: perhaps it's this state where the 80% and 20% are more in harmony within the mind. Where what we create with our minds is appreciated, and the outer loop that critiques ourselves lays quiet. 'Flow' is achieved.
Everything becomes an autonomous loop: which is the study of Cybernetics, and (coincidentally?) the birthplace of AI.
If we follow the pattern of simulating biology, I would expect some ratio of compute could be determined 'optimal' for the new Dream-RSI technique recently: https://www.dream-rsi.com/ to eventually move towards '80%' of compute for autonomously controlled systems, and 20% towards 'something else'. The ratio won't be there in the beginning because an AI system has different autonomous needs.
Through testing and iteration, we'll arrive at some ratio as technology matures: my guess is it will match the one we find in our own heads: 80% for autonomous functions, 20% for creativity.
Keep in mind, dreaming and recursive self-improvement as it is now, is a big unknown: nobody knows what ratio is best, but honestly it's less important because we're all looking at 'Quality' of results right now.
But as the technology matures and moves into robotics and more, and more complexity is required to 'do work': I expect 80% to be accurate.
The result is the same: mindless scrolling consumes 80% of my brain while the 20% struggles to ever get anything done :)
Oh, so Moravec’s Paradox is not really a paradox, it’s just an illusion! ;-)
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.
So, what we colloquially call 'reptile brain' turns out to be somewhat accurate.
There is some truth (but not accuracy) to it, but not for this reason.
This article is about brainstem (aka hindbrain) vs the rest (midbrain + forebrain).
Evolutionally older animal lineages like fish, reptiles, birds all have midbrain + forebrain as well as the brainstem, so reptilian brain != brainstem.
Where there is some truth to our older "reptilian" brain is that the part of the forebrain called the pallium, that exists even in fish (& reptiles), has much expanded/evolved in mammals giving us our cortex and hippocampus, so you could kinda say that we have a reptilian brain + cortex. Note though that mammals didn't evolve from reptiles - they evolved in parallel from a common ancestor, so maybe better to say we have a fish brain + cortex (& hippocampus).
While the cortex is what gives mammals their intelligence, in birds the pallium evolved in a different way to give them theirs.
am no expert in brain development, still have read about evolution. I like aspects of the way you mentioned this, but seems that putting cortex separately from fish brain isn't quite right. As you mentioned, the cortex is simply a part of the fish brain that evolved much (much, much) larger than a fish's. Maybe:
Fish Brain = brain stem + small cortex (+ other parts of brain)
Human Brain = brain stem + gigantic cortex (+ other parts of brain)
Sorry, know this is splitting hairs, but just thought it a useful distinction to make.
That's not quite right - a fish does not have a cortex.
The pallium of a fish and mammal are structured differently. A fish's (& bird's) pallium has a clustered (aka "nuclear") organization, while a mammal's has a mostly layered organization which is what is referred to as the cortex.
There is also more to a brain than just brainstem + pallium. In a vertebrate it's brainstem (aka hindbrain) + midbrain + forebrain, with the pallium being part of the forebrain.
Hm, I’m of two minds on this one.
I'm of more than two minds all the time. (A bunch of my friends are, too...)
I thought this was widely known, at least for males, where the second one can be found in the lower half of the body.
I don’t think the medical community has believed as the article claims for nearly a century.
Most animal brains have three very different organs in the brain: the cerebrum, cerebellum, and the limbic system (which itself is further divided into numerous differentiated types of tissues)
TFA refers to the evolutionarily history of the brain, not the specialised functionality of different parts of the brain.
that's funny when I was in junior school, 15 years ago, I said in the classroom during science class, that we have 2 brains. everyone including my teacher were laughed at me.
There's a very interesting split-brain experiment [1] and Joe Scott's video about it [2]
TL;DW: Doctors treated corpus callosotomy by severing the bundle of nerve fibers that connect hemispheres of the brain. The surgery effectively stopped seizures from spreading. Left hemisphere handles language, speech, and logical interpretation, right hemisphere handles visual, spatial, and literal tasks.
Because human eyes send visual information to opposite sides of the brain, researchers could show images only to the non-speaking right brain. The right brain could see and physically react to the image (like picking up a matching object with the left hand), but the patient couldn't verbally explain what they were seeing because the left brain was literally in the dark. Instead of saying "I don't know," the speaking left brain would instantly and confidently invent a logical—but completely fake—justification for the action.
[1]: https://en.wikipedia.org/wiki/Split-brain [2]: https://www.youtube.com/watch?v=_TYuTid9a6k
Isn’t it funny how Freud, and probably earlier thinkers, have suggested exactly that the mind is layered like this.
How occurate its any experts ?
I worked with a doctor once to build a 3D Model of the brain apertures.
Disclaimer: the work presents these as spiritual/meditational reference points, not established neuroanatomical structures.
Textual reconstruction of the “Brain Apertures” diagram used in the Radhasoami/Surat Shabd Yoga tradition. The named “apertures” are spiritual/meditational reference points in this tradition; labels such as temporal lobe, occipital lobe, cerebellum and brain stem are anatomical landmarks shown in the source diagram in the doc below.
Some details here: https://docs.google.com/document/d/1N9KxIWNF_z9twZurRgkTLljf...
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?
I wasn't expecting to get hit by AI generated slop on Standford's website. At least mark the article as being produced by AI.
The dramatic colon, the obligatory closing metaphor, makes me ill.
I expected an article full of basic medical jargon: cerebrum, cerebellum, cortex, synapse, etc. Instead it's talking about "forebrain" and "hindbrain". This sounds remarkably unscientific.
Which is the one zombies hunger for and which is the one driving their unstoppable hunger? Maybe they just really miss having their brain whole again, and eating and walking is the only thing they know?
Does each separate “organ” here have any relationship to the two separate functions identified in “Thinking, Fast and Slow”?
In short, no. The two types of thinking are both forebrain activity. One comes to a quick guess with pattern matching, the other goes slower with reasoning. It could be that some fast thinking is influenced by the hindbrain in some way, but the thoughts themselves are constructs in the conscious mind that inhabits the frontal lobes.
I learned of the Triune Brain through Carl Sagan's book The Dragons of Eden. It was an engaging, story-telling approach to a somewhat, in hindsight controversial concept. It sounds (oversimplified) like the paper the article describes here is an embryological validation of this model.
Tabloid like headline...
Pity about the dumbed down for dummies, fake marketing from Stanford.
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."
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.
Not just humans… all mammals.
[dupe] https://news.ycombinator.com/item?id=49755533
Stanford researcher discovers his head and his ass aren't the same thing.
I honestly can't wait for AI to analyze the brain so we can truly understand the composition of it.
I always come back to this man and it ... no pun intended.. really blows my mind.
https://www.cbc.ca/radio/asithappens/as-it-happens-thursday-...
Terrible headline, cool research.
The brain is a composit of cells from two lineages that separate very early in development and reflect a deeper spatial and functional separation deep in the history of metazoan (read: animal) evolution.
Tying all this to humans specifically is just confusing. This is something that’s seen in a substantial portion of animals, and as such has nothing to do with “ poetry, mathematics and wondering about our own origins”. These features of humans evolved hundreds of millions of years after this two lineage composite organization of animal brains evolved.
I wish the article hadn’t gone out of its way in confusing these issues to push the “relevance” of the research. It’s a pretty remarkable finding anyway.
That headline's as psyoppy as "schizophrenia".
My GF says I have neither.
Made me think of “Brainscan”, awesome sci-fi from the 90s.
I've just being doing some googling to try to understand this research better.
It seems that it's been known for a while that more primitive animals have/had functionally distinct front (sensory) and rear (motor + autonomic) neural systems, with different genes (Otx, Gbx) associated with each. In 2003 it was shown that an extant species, acorn worms, have this front/sensory, rear/motor neural division, assumed to date back to the pre-chordates.
In vertebrates we also see this association of Otx gene expression in the mid/forebrain and Gbx in the hindbrain, but it had been assumed that these "two halves" of the brain had fused long ago... What this new research shows is that this fusion only happens during development of the embryo, which seems to be a fairly common phenomena "Ontogeny recapitulates phylogeny" whereby embryonic development follows the same steps as evolution (e.g. human embryo also has a tail, chicken embryo has teeth).
Of course the front/sensory and rear/motor neural systems aren't totally isolated, since the sensory signals serve to steer the motor programs running in the back, and our brain still follows this primitive division of functionality.
the forebrain, and hindbrain, dont merge during development, and they are not derived of radically different cells, and they originate from the same process. the difference between them is expressive regulation.
wikipedia being what it is, on par with secondary literature gives an overview of brain and nervous system origin.
https://en.wikipedia.org/wiki/Development_of_the_nervous_sys...
the primary discipline is embryology, and if you view the progression from cellular to somatic, it is quite clear that structure of nervous system, and brain are early events during organogenesis, and are derived from contact and signalling between cellular plates. there is a gradient derived signal, that induces disparate potency of genetic expression. there is however, not , two individual centers of cellular genesis, all neural cells are derived from same cell cell interaction, and induced to take a constrained set of functionalities based on signal amplitudes.
https://embryology.oit.duke.edu/neuro/neuro.html
the original research in question did not discover a two brain merger, thats a tragic misinterpretation that is doing disservice, and is not even the claim of the research.
the discovery is the difference in genetic expression that required a different cultural regime for hindbrain neurons invitro. previously the paradigm was that forebrain, and hindbrain required almost similar culture, and this discovery allows realization of that fact, leading to a cultural regime promoting invitro hindbrain neuroculture.
AI is not a brain, now pay me.
Thread about this from yesterday: https://news.ycombinator.com/item?id=49755533
I wonder if there is a principle here we can apply to neural nets like dividing up the layers for different tasks (no not MoE but something more fundamental).
Didn’t we fix the title yesterday?