[HN Gopher] Cubic millimetre of brain mapped in spectacular detail
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Cubic millimetre of brain mapped in spectacular detail
Author : geox
Score : 59 points
Date : 2024-05-09 21:36 UTC (1 hours ago)
(HTM) web link (www.nature.com)
(TXT) w3m dump (www.nature.com)
| teuobk wrote:
| The interactive visualization is pretty great. Try zooming in on
| the slices and then scrolling up or down through the layers. Also
| try zooming in on the 3D model. Notice how hovering over any part
| of a neuron highlights all parts of that neuron:
|
| http://h01-dot-neuroglancer-demo.appspot.com/#!gs://h01-rele...
| jamiek88 wrote:
| My god. That is stunning.
|
| To think that's one single millimeter of our brain and look at
| all those connections.
|
| Now I understand why crows can be so smart walnut sized brain
| be damned.
|
| What an amazing thing brains are.
|
| Possibly the most complex things in the universe.
|
| Is it complex enough to understand itself though? Is that
| logically even possible?
| ignoramous wrote:
| I wonder if we manage to annotate this much level of detail
| about our brain, and then let (some variant of the current)
| models train on it, will those intrinsically end up
| generalizing a model for intelligence?
| nicklecompte wrote:
| I think you would also need the epigenetic side, which is
| very poorly understood:
| https://www.universityofcalifornia.edu/news/biologists-
| trans...
|
| We have more detail than this about the C. elegans nematode
| brain, yet we still no clue how nematode intelligence
| actually works.
| nicklecompte wrote:
| Crow/parrot brains are tiny but in terms of neuron count they
| are twice as dense as primate brains (including ours): https:
| //www.sciencedirect.com/science/article/pii/S096098221...
|
| If someone did this experiment with a crow brain I imagine it
| would look "twice as complex" (whatever that might mean). 250
| million years of evolution separates mammals from birds.
| CSSer wrote:
| For some people, this is all you need (sorry, couldn't resist)!
| eminence32 wrote:
| > cut the sample into around 5,000 slices -- each just 34
| nanometres thick -- that could be imaged using electron
| microscopes.
|
| Does anyone have any insight into how this is done without
| damaging the sample?
| talsit wrote:
| Using a Microtome (https://en.m.wikipedia.org/wiki/Microtome).
| dekhn wrote:
| The sample is stained (to make thigns visible), then embedded
| in a resin, then cut with a very sharp diamond knife and the
| slices are captured by the tape reel.
|
| Paper:
| https://www.biorxiv.org/content/10.1101/2021.05.29.446289v4 See
| Figure 1.
|
| The ATUM is described in more detail here https://www.eden-
| instruments.com/en/ex-situ-equipments/rmc-e...
|
| and there's a bunch of nice photos and explanations here
| https://www.wormatlas.org/EMmethods/ATUM.htm
|
| TL;DR this project is reaping all the benefits of the 21st
| century.
| posnet wrote:
| 1.4 PB/mm^3 (petabytes per millimeter cubed)x1260 cm^3 (cubic
| centimeters, large human brain) = 1.76x10^21 bytes = 1.76 ZB
| (zetabytes)
| bahrant wrote:
| wow
| gary17the wrote:
| [AI] "Frontier [supercomputer]: the storage capacity is
| reported to be up to 700 petabytes (PB)" (0.0007 ZB).
|
| [AI] "The installed base of global data storage capacity [is]
| expected to increase to around 16 zettabytes in 2025".
|
| Thus, even the largest supercomputer on Earth cannot store more
| than 4 percent of state of a single human brain. Even all the
| servers on the entire Internet could store state of only 9
| human brains.
|
| Astonishing.
| g4zj wrote:
| Is there a name for the somewhat uncomfortable feeling caused by
| seeing something like this? I wish I could better describe it. I
| just somehow feel a bit strange being presented with microscopic
| images of brain matter. Is that normal?
| ignoramous wrote:
| Trypophobia, visceral, uncanny, squeamish?
| greenbit wrote:
| Is it the shapes, similar to how patterns of holes can disturb
| some people? Or is it more abstract, like "unknowable fragments
| of someone's inner-most reality flowed through there"? Not that
| I have a name for it either way. The very shape of it (in
| context) might represent an aspect of memory or personality or
| who knows what.
| g4zj wrote:
| > "unknowable fragments of someone's inner-most reality
| flowed through there"
|
| It's definitely along these lines. Like so much (everything?)
| that is us happens amongst this tiny little mesh of
| connections. It's just eerie, isn't it?
|
| Sorry for the mundane, slightly off-topic question. This is
| far outside my areas of knowledge, but I thought I'd ask
| anyhow. :)
| throwup238 wrote:
| _> The 3D map covers a volume of about one cubic millimetre, one-
| millionth of a whole brain, and contains roughly 57,000 cells and
| 150 million synapses -- the connections between neurons._
|
| This is great and provides a hard data point for some napkin math
| on how big a neural network model would have to be to emulate the
| human brain. 150 million synapses / 57,000 neurons is an average
| of 2,632 synapses per neuron. The adult human brain has 100 (+-
| 20) billion or 1e11 neurons so assuming the average rate of
| synapse/neuron holds, that's 2.6e14 total synapses.
|
| Assuming 1 parameter per synapse, that'd make the minimum viable
| model several hundred times larger than state of the art GPT4
| (according to the rumored 1.8e12 parameters). I don't think
| that's granular enough and we'd need to assume 10-100 ion
| channels per synapse and I think at least 10 parameters per ion
| channel, putting the number closer to 2.6e16+ parameters, or 4+
| orders of magnitude bigger than GPT4.
|
| There are other problems of course like implementing
| neuroplasticity, but it's a fun ball park calculation. Computing
| power should get there around 2048:
| https://news.ycombinator.com/item?id=38919548
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