Comment on Doug Clow on the Whole Brain Emulation roadmap by Luke Parrish

2010-07-30T00:14:15+01:00

Slicing for cryopreservation purposes is easier than slicing for scanning purposes as the slice can be around a millimeter thick. UV lasers are ~250 nm wide, so only ~1/4000th of the tissue would be intersected.

Once that is achieved, the three methods of revival would be destructive scan, nondestructive scan, and biological reconstruction. The latter could be facilitated by selectively applied printed magnetics and glues that permit the tissue to join at the original spots and seal shut blood vessels. Stem cells, prosthetic neurons and dendrites, etc. could all be sprayed into place during the reanimation process.

Comment on Doug Clow on the Whole Brain Emulation roadmap by Paul Crowley

2010-07-29T06:32:12+01:00

people betting against the future advances of science have not had a very good track record.

Do we know this? Perhaps the examples of people betting against and being wrong are just more famous than the perhaps more numerous examples of them being right.

Comment on Doug Clow on the Whole Brain Emulation roadmap by Pore G

2010-07-29T05:35:30+01:00

Thanks for tackling some of the issues Doug.

Disagree that prion protein in C-J shows that protein conformation is crucial for scale separation. The prion protein causes native proteins to get out of their own proper folding equilibriums.

You’ll find much better examples of why proteins are important by looking at things like subcellular protein concentration differences (i.e. local ribosome synthesis) and the protein composition at post-synaptic densities.

They key is not whether these different proteins, and their folding state, matter. Of course they do. And of course individual amino acids do, and of course the atoms that make them up do. The key question is whether one can model neuron classes, or neuron subclasses, as one distinct type, and accept that you are missing some variability between neurons, but still profitably predict the variation between individual brains. That is scale separation.

Agree that nanoassembly doesn’t make so much sense. And it might not in the future too. But on the meta level I am willing to accept that people betting against the future advances of science have not had a very good track record.

On imaging side, you seem correct in noting that the best approach would probably be to slice up the brain into little slices and imagine those individually. You say:

“That’s not feasible without destroying at least half of what you’re trying to analyse. When you slice something, you basically smash up a thin column of stuff in the path of the knife (or laser beam, or whatever). And even if you invented some magical way of preparing the samples without that mechanical damage, you’d still have to pull the network of synapses apart in order to expose the surfaces to microscopy.”

There will presumably be some mechanical damage. But one could imagine some kind of knife / laser beam that would imagine as it slices, in the z direction, to capture that information before it is destroyed. This could then be reconstructed later.

Moreover, who’s to say that the slight slight damage from the small laserbeam will be too much damage? Especially if the laser beam could avoid crucial locations such as synapses or dendritic arborizations, which is certainly technically feasible, then you should be fine.

You note that simulating a brain may be easier, and a “better plan.” But there are large ethical and possibly existential risks to this, whereas simply restoring a dead brain to a live one is something that humanity could conceivably be more willing to cope with. Agree that recreating / emulating one individual dead brain should be much more difficult.

They did talk about EM being really close to the resolution necessary. But you may be interested in reading about a new laser that might be able to go even “deeper”, http://home.slac.stanford.edu/pressreleases/2010/20100630.htm .

ciphergoth comments on Doug Clow on the Whole Brain Emulation roadmap

Comment on Doug Clow on the Whole Brain Emulation roadmap by Luke Parrish

Comment on Doug Clow on the Whole Brain Emulation roadmap by Paul Crowley

Comment on Doug Clow on the Whole Brain Emulation roadmap by Pore G