OpenWorm – A computational model of C. elegans worm
github.com
github.com
Neurons are similar, they are incredibly sophisticated biological machines, with billions of DNA base pairs controlling their behavior. The emergent behavior of neurons in both biological and AI systems are pretty fascinating
Total genome size of C elegans is 100M.
This tiny animal code contain all the systems and members of this creature. Birth,creation,death, feeding,growth, movement, sensation.. etc inside the universe. There is no difference this animal and bee or human beings.
"In order to be the author of the action directed towards the creation of the bee in question, a power and will are necessary that are vast enough to know and secure the conditions for the life of the bee, and its members, and its relationship with the universe. Therefore, the one who performs the particular action can only perform it thus perfectly by having authority over most of the universe." from Quran's light
"The neurons do not fire action potentials, and do not express any voltage-gated sodium channels." [1]
That makes the fact that it can develop a nicotine addiction even more fascinating.
"Nicotine dependence can also be studied using C. elegans because it exhibits behavioral responses to nicotine that parallel those of mammals. These responses include acute response, tolerance, withdrawal, and sensitization." [1]
Bribe the IDE. "Fine, if you don't want to use this language, rewrite it in Rust."
This an old and incorrect belief that largely derives from the difficulty of putting electrodes into their teeny, tiny neurons. Close relatives of C elegans that are larger (and hence more easily experimented on) do have action potentials, and for some neurons in C elegans, we also have good evidence of action potentials [1, 2]. Absence of evidence is not evidence of absence.
[1] Lockery SR, Goodman MB. The quest for action potentials in C. elegans neurons hits a plateau. Nat Neurosci. 2009 Apr;12(4):377-8. doi: 10.1038/nn0409-377. PMID: 19322241; PMCID: PMC3951993.
[2] Jiang, J., Su, Y., Zhang, R. et al. C. elegans enteric motor neurons fire synchronized action potentials underlying the defecation motor program. Nat Commun 13, 2783 (2022). https://doi.org/10.1038/s41467-022-30452-y
I'd think the simulation has to get it right, and so needs to simulate action potentials if the worm has them, or not simulate them (but whatever the worm has instead) if not, right? Or could the simulation still be incorrect and only based on current assumptions, but getting this wrong still allows some worm-like behavior?
I really wish the readme/FAQ would talk a bit more about the worm and the simulation, rather than have 80% of their content be about Docker, though, so that I could learn more what cells it actually simulates.
One way to answer that would be to add and remove such mechanisms to see if it would lead to different behavior.
"With four parameters I can fit an elephant, and with five I can make him wiggle his trunk." - John von Neumann [0]
As of this year there are 3 known neuron classes in C. elegans that do exhibit action potentials. The rest exhibit graded potentials.
Somewhat related, there is a roughly inverse correlation between neuron count and "computational power per neuron", "older and simpler" critters' neurons are more likely to be "less specialized" and more likely to use hundreds of different chemicals for transmitting intercellular signals, while "newer and more advanced" critters' neurons are more likely to be "specialized" and use just one chemical for transmitting intercellular signals
Action potential are almost strictly INTRAcellular events (minor exception being ephaptic effects) that are converted in a surprisingly noisy way into presynaptic transmitter release and variable postsynaptic changes in conductances.
Action potential are a clever kludge necessitated by being big and having long axons and needing to act quickly.
The APs discovered by Liu et al (2018) are generated by calcium, not sodium currents, so one could even argue that they aren't action potentials in the strict sense. Also, they seem to be rather difficult to elicit, and it's still not clear whether neural computation in C elegans is mostly AP-mediated, or if APs are the exception rather than the rule.
Liu, Q., Kidd, P. B., Dobosiewicz, M. & Bargmann, C. I. C. elegans AWA olfactory neurons fire calcium-mediated all-or-none action potentials. Cell 175, 57–70 e17 (2018) https://doi.org/10.1016/j.cell.2018.08.018
Does the underlying chemistry define if its an action potential or not? I thought an AP just needed a voltage differential regardless if its from calcium or sodium.
Because they've been trained for such an incredibly long period of time.
A virtual "neuron" by contrast is a very simple mathematical abstraction. It's vastly less computational complexity than a biological neuron. A connectome is only a very coarse grained map of how neurons relate, not a complete "neural network" layout. Not even close.
It might be possible to model a biological neuron using a sub-neural-network with state within a larger neural network, but assuming that can be computationally equivalent we don't really know how many equivalent computational "neurons" would be required to model the full breadth of computationally relevant biological neuron behavior.
So a worm with 302 biological neurons could be computationally equivalent to billions of virtual neurons. We really don't know.
Given that neurons have memory it may look a little like LSTM networks, and biological neural networks are not just feed forward so they're definitely closer to an RNN.
The above is why I laugh at the mind uploading people and would only stop laughing if we could both understand and model the relevant behavior of biological neurons and somehow extract usable state from living neurons. That's all 100% science fiction at the moment. The people who think we are about to upload minds are ignorant of biology.
The even bigger issue is when mind uploading people fully admit this issue and try to claim some philosophical reason why it doesn't matter, and we should all be excited about tech to make what amounts to an interactive epitaph.
I think it's great that this work is still going on, it may produce insights about functioning of nervous systems. But the difficulties are fierce, and we're making very slow and difficult progress in an immense unknown area.
What?
This is the first time I read that. That's fascinating. So they are very different then compared to what we have in humans? How do they work? Where can I read about this?
As I said, this is possibly out-of-date information. If there is someone here from the neuroscience field, they can probably make a better comment.
Not all the cells of the nervous system produce the type of spike that define the scope of the spiking neuron models. For example, cochlear hair cells, retinal receptor cells, and retinal bipolar cells do not spike.
The idea is that spiking is one way to have a more robust signal over long distances: Crustaceans often have nonspiking local interneurons and spiking projection neurons and motor neurons. The problem of fast, reliable electrical signal transduction over long distances is also solved by having more insulation (particularly in vertebrates) or having thicker cables (particularly in invertebrates).
Humans also have non-spiking neurons with graded synapses in the retina.
The technical fact that the genome was artificially synthesized is just showmanship - they still had to put into an existing cell.
It's like claiming you made a car from scratch by replacing a chip - which you've copied from the existing chip but left a few bits out - and now the indicators don't work, but you can still sort of drive.
1. The first kind of AI research is more like engineering for example creating self driving cars, language translation & object recognition.
2. The second kind of AI research is trying to replicate the intelligence of living organisms (humans, worms) with models that are consistent with what cognitive scientist have.
An example for such a system is one that would pick up any human language with very little supervision. Like children for example.
Open worm seems like no. 2. Any one have any interesting resources for no. 2 type AI? I would love to explore it some more.
Well, when I looked at it I was shocked: it doesn't work! sure it could replicate some basic movements but many things that the stupid worm actually does where still a mystery. The docs didn't seem like people were close to figure it out either. And sure enough, a few years later seems like they gave up. And afaik that hyped European brain emulation project also folded in the midst of corruption allegations no less.
I think we don't understand any of this and we seem very far from it too. I think it's back to science fiction novels for a while.
No- each synapse has its particular neurotransmitters, and the distance, size, shape, number of receptors, and associated glial cells have very large impacts on transmission. The distance and thickness of axons also impacts the strength of signal delivered. That's all very hard to measure.
Neurons are also very sensitive to signal strength and timing. Eg inhibitory synapses work by opening holes in the cell wall, causing them to leak charge over time. You get that rate slightly wrong and it can hugely change the behavior of the cell.
The connectome is a bit like an untrained model of insane complexity, and each neuron has several weights that describe behavior over time as well as in direct response to signals. Without the weights it can't be emulated.
[1] https://hub.jhu.edu/2023/03/09/scientists-complete-first-map...
This makes neurokernel [1] and the like seem just a tad ambitious. Good luck to them though.
I have downloaded the complete (so far) Drosphilia connectome and working to create an emulation. I am exploring Hypervectors to emulate neurons or neuropils but still working on the concept. I have tried many other ideas including Adjacency Matrices and Function programming where each Function is some part of the animal nervous system (e.g. with C elegans think Sensory, Interneuron and Motor as 3 distinct functions and programs).
The C elegans emulation was also done in a single Python app, translated to several other programming languages, that also showed clear emulation in many different robots. Ablation tests demonstrated how the emulated nervous system is congruent to the biological nervous system through observable behaviors of both.
There are two extremes on the evolutionary continuum of nervous systems with the worm's brain on one end and the human brain on the other. However, even with the Worm's nervous system, we can clearly see general intelligence and a gateway to AGI.
My undergrad degree capstone project was a flow-based visual C. elegans strain builder[1]. The team worked with two researchers who taught us a lot about genetics and basic C. elegans biology. They are a fascinating model organism, and it was a super fun project to work on. Even though it's got a very small potential userbase, it did have a potential userbase (which was more than you could say about most capstone projects). We used some interesting technology to build it (Tauri[2]: Rust + Web Frontend), learned some biology along the way, and ended up with a great prototype.
Since none of the software team had any background in genetics, modeling the data was pretty difficult. We'd meet with researchers, they'd teach us new genetics concept, we'd build our models, then the next week they'd say "OH we forgot to tell you about this caveat", then we'd go back to the drawing board, update the schema (thank heavens for migrations), rinse and repeat. It was a lot of fun though :) I couldn't have asked for much more out of a capstone project.
Doesn’t sound that different from standard business software development!
Fascinating project. Really enjoyed reading about it - well done!
How accurate can neuron simulation be without underlying chemistry and physics?
This project is often used to joke about the limitation of computational modelling of nervous system. If you can't compute the behavious of an effing worm with mere ~300 neurons, whats the point of all hot-air around connectomics (mapping connections of the brain). Connectomics used to be a big word when I started my Ph.D.. The apologists are always like, "real neuron is way too complicated!".
IMHO, chemical computations are often over-looked in neural "computation" communities which are extremely hard to model. Forgetting modelling, we don't know reaction parameters of most proteins and other molecules involved. Electrical side of computation is easy to measure and one can understand why we started with it. There are a thousands types of proteins even in a small structure such as synapse, and individual protein can implement interesting non-linear computation. E.g. CaMKII can implement and bistable switch (flip-flop) and thus store 1-bit of memory using just a few molecules (the real story is a much more complicated).
On a scale of one to ten, how sick are you of people asking you about Neal Stephenson - "The Fall, or Dodge in Hell"?
In case anyone is worried I write software in Rust and Golang now and my life has improved significantly since the origins of this worm and people taking dep injection frame works seriously. :D
However, it should be noted that the field, and specifically this line of research, hasn't produced much in the way of results in 10+ years. University of Oregon planned (though I can't tell if they ever developed) NemaSys[0] ~1997. OpenWorm has been exploring this since 2011. Project Nemaload explored it a bit from 2011-2013.[1] But each project ran into three problems:
- Knowing the connections isn't enough. We also need to know the weights and thresholds. We don't know how to read them from a living worm.[2]
- C. elegans is able to learn by changing the weights. We don't know how weights and thresholds are changed in a living worm.[2]
- Funding [3]
The best we can do is modeling a generic worm - pretraining and running the neural network with fixed weights. Thus, no worm is "uploaded" because we can't read the weights, and these simulations are far from realistic because they are not capable of learning. Hence, it's merely a boring artificial neural network, not a brain emulation. Relevant neural recording technologies are needed to collect data from living worms, but they remain undeveloped (but in progress?[4][5][6]), and the funding simply isn't there.
OpenWorm got the idea to plug their connectome into a Lego robot[7] and got it to exhibit the tap-withdrawal behavior of the nematode, but it had technical limitations preventing easy modification of the connectome or introduction of new models of neural dynamics. JHU Applied Physics Lab extended the work by using a basic integrate and fire model to simulate the neurons and assigned weights by determining the proportion to the total number of synapses the two neurons on either side of the synapses shared and in the end got the simulated worm to reverse direction when bumping into walls.[8] At this point, humanity seems to have abandoned emulated worm driven mechanisms which is honestly kind of a loss.
There's no real ending to this comment. Love this project, loves what it stands for, looking forward to seeing progress in this field. And a lot of this information was pulled from this blog post[9] which was also mentioned in the comments somewhere.
[0] https://web.archive.org/web/20030115124331/http://www.csi.uo...
[1] https://github.com/nemaload
[2] https://www.jefftk.com/p/we-havent-uploaded-worms
[3] https://www.quora.com/Is-Larry-Page-funding-any-neuroscience...
[4] https://arxiv.org/pdf/2109.10474.pdf
[5] https://onlinelibrary.wiley.com/doi/10.1002/cyto.a.24483
[6] https://www.sciencedirect.com/science/article/pii/S095943882...
[7] https://www.cnn.com/2015/01/21/tech/mci-lego-worm/
[8] https://ccneuro.org/2018/proceedings/1149.pdf
[9] https://www.lesswrong.com/posts/mHqQxwKuzZS69CXX5/whole-brai...
Watching that lego worm really zapped my brain, seemed like we were on the cusp of something. Maybe we still are, and just misjudged the time-scale on progress.
I briefly considered doing a postdoc in one of these labs, because I love working worms and agree with your proposition that next logical step in neuroscience is modeling and fully understanding an entire organism. The late Sydney Brenner asked for the same in 2011 [1].
But most academic labs doing well won’t even consider a postdoc application from a student who didn’t work in the exact same field. Solidified my decision to never be part of the Ponzi scheme that is academic research.
The beauty of C. Elegans is that you actually need very little to start working with them. All the strains are available for 10 bucks a pop, you can do most work at room temperature. I only need to invest on a very custom (but not necessarily outrageously expensive) microscope to start working on this topic in my garage. Which I absolutely plan to start in the next few years. I’ve done the math and it’ll cost me less than owning a cheap boat lol. If anyone wants to fund me I’ll be open to it too :)
1. Sydney, B. & Sejnowski, T. J. Understanding the human brain. Science 334, 567 (2011).
It's very exciting to me when a theory makes predictions, and those predictions turn out to be true - it's beautiful.
OpenWorm - https://news.ycombinator.com/item?id=29045198 - Oct 2021 (110 comments)
OpenWorm – Create a virtual C. elegans nematode - https://news.ycombinator.com/item?id=8949408 - Jan 2015 (12 comments)
OpenWorm: A Digital Organism In Your Browser - https://news.ycombinator.com/item?id=7613732 - April 2014 (47 comments)
Openworm: c.elegans worm simulation - https://news.ycombinator.com/item?id=4208454 - July 2012 (14 comments)
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edit: Possibly baked already at http://wormsim.org/
I guess if the computer mode really is true on a physical level it is owed the same (minimal) level of decency somehow.
I suspect people are just leaning on the intuitive answer (that it is just a computer program), and the fact that we just don’t have the ability to simulate anything that has, like, obvious rights yet. I don’t think the first will really stand up to scrutiny, and the second is clearly a temporary solution (to the extent that it even is a solution).
edit. this comment seems unpopular, my intent was to defend the worm against trolls :)
[0] - https://github.com/openworm/c302 (linked in the original github page)
When it comes to brains, I don't know if anyone knows what might be the simplest sufficient model that would usefully replicate them, even if you specify "usefully" well enough to know if this is about fundamentals of intelligence or about the impact of drugs on cognition, which are two completely different standards.
For example, perceptrons are a toy model, but modern AI can do more in (breadth XOR single-skill performance in various domains) than any single human, even with much smaller parameter counts than we have synapses; but the broad-skilled ones also mess up in inhuman ways, like being equally good at advanced calculus as basic arithmetic, or being a poet at the level of stereotypical teenager but in every language simultaneously.
If anyone's made a neutral network that can get high on simulated caffeine — and I'm not saying it hasn't been done — it's not reached any of the places I follow discussions on this kind of thing. (Google didn't help, results were about software named Caffeine and non-artificial neurones).
Cells duplicate, but can you make a cell without splitting one in 2?
We're physics too, but we don't know how it all fits together.
If a sub-part of us that knows less than we do can make a copy of us, despite not knowing how it all works, that's an existence proof that we don't need to understand how it all works to make a copy of us.
But strictly speaking, as we understand it, it's not possible to replicate something exactly without recapitulating the exact laws and running a deterministic simulation, which is not practical.
I don't think anybody is really attempting to exactly replicate things, but rather to create a physical model which can be calcualted and contains enough similarity or transferrability to be able to make accurate generalized predictions about the behavior of the simulated system. How and why that works with modern math methods is still somewhat mysterious. The most useful thing written about that so far is https://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness...
> Our main goal is to build the world's first virtual organism - an in-silico implementation of a living creature - for the purpose of achieving an understanding of the events and mechanisms of living cells.
This blog post is interesting: "Whole Brain Emulation: No Progress on C. elegans After 10 Years" https://www.lesswrong.com/posts/mHqQxwKuzZS69CXX5/whole-brai... As other mentioned in the comments of the post, it is certainly also a matter of funding, but still I think it is very interesting how we still struggle to simulate a 302 cell worm, while some people expect an artificial superintelligence in the next ten years.
Edit: I am surprised at the downvotes. In general, we learn from the nature, but aping it usually proved too difficult and often unpractical at the same time. Do we really want to replicate worm intelligence for practical purposes, or do we want something different?
I would say that a machine which can, say, analyze chemical compounds for their potential biological functions, is a very practical form of "intelligence" and yet very far from any biological intelligence that was ever produced in vivo. Worms cannot do that and even humans struggle with such tasks.
This is not true for how this 302 cell organism works. We don't know and struggle to understand. That's actually the reason why the project exists. To find out how everything works with an bottom-up approach.
While we may find shortcuts or even superior forms of intelligence without understanding how intelligence works in biological creatures, it is still curious how we struggle even with a "simple" organism like C.elegans.
And most of the details of bird flight were not exactly discovered till well after commercial air travel was commonplace.
We still don't know how cells in C. elegans work together. It's neither visible nor explainable on a satisfying level.
The Wright flyer didn't flap, and the wings only superficially look like anything a bird has.
That is true and it shows even more how important observabilty is for science and engineering. That's also why a simulation that actually provides an accurate enough model of reality might help us so much. The problem with AI right now is, that we try or even claim to understand Unix by mimicking the functionality of transistors.
> The Wright flyer didn't flap, and the wings only superficially look like anything a bird has.
They tried to mimick bird wings when coming up with flight control mechanisms.
https://youtube.com/watch?v=eaYIU6YXr3w?t=106
I’m not sure the timestamp works but it’s at 1:46
The whole deep learning stuff is basically roughly inspired by a tiny part of the visual cortex (see also Neocognitron). I am not sure how brain diseases can be understood by looking at such simplistic (yet powerful) machines.