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Cubic millimetre of brain mapped at nanoscale resolution

nature.com

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Re: Cubic millimetre of brain mapped at nanoscale resolution

#11

Post by [deleted] »

jamiek88 wrote: post #9
teuobk wrote: post #2

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...

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?

[deleted]

Re: Cubic millimetre of brain mapped at nanoscale resolution

#12

Post by throwup238 »

> 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

Re: Cubic millimetre of brain mapped at nanoscale resolution

#13

Post by ignoramous »

jamiek88 wrote: post #9
teuobk wrote: post #2

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...

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?

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?

Re: Cubic millimetre of brain mapped at nanoscale resolution

#14

Post by nicklecompte »

jamiek88 wrote: post #9
teuobk wrote: post #2

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...

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?

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.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#15

Post by ignoramous »

g4zj wrote: post #10

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?

Trypophobia, visceral, uncanny, squeamish?

Re: Cubic millimetre of brain mapped at nanoscale resolution

#16

Post by greenbit »

g4zj wrote: post #10

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?

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.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#17

Post by nicklecompte »

ignoramous wrote: post #13
jamiek88 wrote: post #9

Earlier quoted context omitted.

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?

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?

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.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#18

Post by g4zj »

greenbit wrote: post #16
g4zj wrote: post #10

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?

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.

> "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. :)

Re: Cubic millimetre of brain mapped at nanoscale resolution

#19

Post by gary17the »

posnet wrote: post #5

1.4 PB/mm^3 (petabytes per millimeter cubed)×1260 cm^3 (cubic centimeters, large human brain) = 1.76×10^21 bytes = 1.76 ZB (zetabytes)

[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.

Re: Cubic millimetre of brain mapped at nanoscale resolution

#20

Post by gibsonf1 »

throwup238 wrote: post #12

> 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 adu…

Except you’d be missing the part that a neuron is not just a node with a number but a computational system itself.
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