A fragment of human cerebral cortex reconstructed at nanoscale resolution | Hacker News Reader

A fragment of human cerebral cortex reconstructed at nanoscale resolution

science.org

42 pointsisaacfrond19 comments

1.4 petabytes for 1mm3. There are about 1100000mm3 of them in the brain. So we're talking about 1_540_000 petabytes. The web is about 175 zeta bytes, so about 17500 petabytes. So the brain would be 1_540_000 / 17500 = 88 times the size of internet.

Now that's big.

I mean that's true, but at the risk of stating the obvious, people should not be mistaken to think that this represents the "information content" of the brain (except perhaps in a very narrow and technical sense).

If you did such 3D scans at similar resolution of all the hardware comprising the internet, for example, it would be vastly bigger than a human brain. It might even be bigger than all the human brains combined, although I'm not sure. It's not very clear whether such comparisons really mean anything (other than "wow that research team really pulled off something impressive" or "wow there are a lot of very small things in a given volume of matter"). A similar volume of toenails would contain a similar amount of 3D scan data.

my comparison was just based on the size of the data set, not the brain or whatever. I thought about it in the sense that: if we'd ever had to map a complete brain, that would be the size required to store everything.

I have no idea how the brain actually encodes information :-)

There are 10^18 voxels in that cubic mm, so a petabyte (10^15 bytes) is not too bad. Must be a lot of empty space in there.

Put another way: this is pretty close to a football-field-sized cube, filled with sand. Each grain of sand is a voxel. The central bodies (soma) of neurons are about a yard wide at that scale.

So about 1 NSA datacenter.

74 comments. 15 hours ago: https://news.ycombinator.com/item?id=40313193

The internet is getting too full so unfortunately there was only room for one image in the article.

I'm curious. Why store this in voxels? Why not use data structures that that represent the network and that lend themselves to computation?

They are just recording the raw imaging data to enable that type of analysis, which is hard enough.

I imagine it must be quite complex to interpret the biological structure as a logical network, tissues are messy and there are many types of neurons and communication modes. I'm not sure if it's even possible to infer how electric signals will propagate just from a static picture, however detailed it is, do we know how each specific neuron and synapse will behave? We have a general mathematical model, but do we know how the morphology of each element affects its behaviour?

This is probably is a whole other massive research project after this.

health scans from eg MRIs are often given in voxels

How can a cubic millimeter contain 230 millimeters of blood vessels?

https://en.wikipedia.org/wiki/Space-filling_curve

How can a cubic foot contain 230 feet of string?

Some excellent sibling replies but I think you've nailed it in terms of something that's easy to visualise

The same way your <2 meters body can contain 6 meters of intestines.

Same way your lungs have the surface area of a tennis court

The same way each of your cells contains 2 meters of DNA.

Capillaries are around the same width as the central bodies (soma) of neurons

They're thin.

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