31 December 2022

The mind of a worm, the mind of a human, and mind uploading

In 1986, a key paper on the nervous system of the nematode worm Caenorhabditis elegans appeared. It was a fairly complete description of the entire nervous system of the animal: it counted all the neurons (302 then) and a good first pass at counting neural connections (5000 chemical synapses, 600 electrical synapses, and 2000 synapses to muscles).

The paper was subtitled, “The mind of a worm.” 

This subtitle was despite there being nothing about the behaviour or internal states of the species. It was all anatomy.

I think it was called that for a couple of reasons. 

First, co-author Sydney Brenner was a playful writer. He wrote a great column for Current Biology for many years that often showed his wit.

Second, it represented a hope in invertebrate neuroethology that understanding the neural connections of an organism would allow you an almost complete ability to predict the behaviour of that organism. A few papers since have used the phrase “mind of a worm” in homage to the 1986 paper.

So the subtitle was probably a joke, but one the represented a real goal of invertebrate neuroethology: to crack the neural circuitry of animals. Then we’d understand behaviour.

Fast forward to 2022. Our understanding of nervous systems is better. Technology has gotten batter. But a preprint about C. elegans released this year says, “We find that functional connectivity differs from predictions based on anatomy.” 

Wait, what? Wasn’t the promise that that once we had the neural connections, we would have near omniscience about the behaviour of thise worm?

In the world of invertebrate neuroethology. this is kind of yesterday’s news. It’s been decades since neuroethologists gave up on the idea that neural circuitry alone would give you a relatively complete understanding of behaviour. I suspect that idea was already wobbly in 1986 but was pretty clearly abandoned by the 1990s. It was killed by things like the study of neuromodulation in the stomatogastric nervous systems of decapod crustaceans.

But it seems that the news has yet to reach other fields in neuroscience.

After my last post on mind uploading, Ken Hayworth helpfully sent me a link to an article he wrote about mind uploading. I appreciated the writing, particularly this concise summary.

The core of the scientific argument: I am my connectome and (aldehyde stabilized cryopreservation) preserves the connectome

Most of what I said in my review of a book length treatment of the connectome argument is relevant here. In brief:

Invertebrate neuroethology has already tested the connectome hypothesis. The connectome hypothesis didn’t exactly fail, but it certainly under performed. Knowing the connectome of a worm has not revealed the mind of a worm.

The only reason to think, “Sure, the connectome didn’t give us everything we wanted to know in small neural circuits in invertebrates, but it will totally work in humans” is special pleading.

External links

Vitrifying the Connectomic Self: A case for developing Aldehyde Stabilized Cryopreservation into a medical procedure (PDF)

References

Randi F, Sharma AK, Dvali S, Leifer AM. 2022. A functional connectivity atlas of C. elegans measured by neural activation. https://doi.org/10.48550/arXiv.2208.04790

Related posts

Brainbrawl! The Connectome review

If you know how to do mind uploading, please do tell us

 


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