Gruesomeness factor of cryonics methods

Gruesomeness factor of cryonics methods

Joined: May 17th, 2009, 5:13 pm

May 30th, 2009, 2:39 am #1

Here's a mental exercise for you...

Rank the following in order of gruesomeness: severed head, whole brain, sliced brain, full body.

Assume for the moment that all have equal chances of being revived.
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Joined: October 2nd, 2004, 8:27 pm

May 30th, 2009, 4:34 am #2

Severed head, sliced brain, whole brain, full body

Not from my own perspective, but from my perceived probablility of gruesomeness to the public in general.

I do, though, question the unproven ability of brain slices to ever become rejoined without severe damage to the neurons, synapses, etc.

FD
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Joined: May 17th, 2009, 5:13 pm

May 30th, 2009, 6:04 am #3

I'm not sure whether sliced or whole brain comes first in the list, but essentially I agree that both are somewhere between whole-body and severed-head. This is curious since a brain is less humanlike than a severed-head, whereas whole-body is actually more humanlike.

The objective question is, of all the problems to be overcome with a given method, which are the least likely to be solved by technology? These are the ones we must be the most anxious to avoid.

Cloning new organs and limbs is a problem that is about 100% certain to be solved via technology at some point. Stem cell research is already making huge progress in this area. It is a form of damage we can afford to incur. On the other hand, reversing direct freezing damage (where no cryoprotectant is involved) may never be solved by technology. Thus incomplete perfusion is a problem we want to be as sure of avoiding as possible.

Matching and reconnecting neurons based on their position in the tissue and various structural features is something I think quite solvable by technology -- I can certainly think of no reason it would not be. It is a matter of matching patterns and basically reconnecting some disconnected wires. The more the dendrites and cells remain in the same position as when they were seperated, the better. However, a bit of macroscopic warping would not make it impossible to match the proper neuroconnections, since the surrounding terrain would be tend to be very distinctive. If OCR is possible, I can't see why this would not be.

The biggest concern I can think of would be information loss caused by missing material. 250 nanometers is very narrow, but narrower or zero-width would be preferable. Neuron soma are typically between 10000-25000 nanometers across, ranging 4000 to 100000 (ref. wikipedia), so they could probably be stitched back together wherever they are intersected. Dendrites, on the other hand, are a lot narrower, and some of them are going to be destroyed in very intricate areas. But a good bump on the head probably destroys lots of dendrites in very intricate ways too. The question is whether it would be enough information loss to notice.
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Joined: June 5th, 2009, 12:29 am

June 5th, 2009, 1:31 am #4

I believe the repair of brain tissue will be on the forefront of medical research,
insofar as it matters to cryonics revival. Sliced brains? You mean plasticized for exhibition?
That would be the worst imo, but the possibilities of adding components while your rebuilding
is pretty cool XD.
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Joined: May 17th, 2009, 5:13 pm

June 6th, 2009, 6:48 am #5

I admit it is counter-intuitive, but some things make me think slicing may be easier to bring people back from (at least from cryo temperatures) than not-slicing... The cryoprotectant antifreeze could be in place instantly at full-strength by immersing the slice, and you could cool it super-fast to keep it from being poisoned by the antifreeze (so a higher amount can be used, to protect better from freezing). The slice also wouldn't crack because it is cooled so evenly.

I first got the idea of slicing from plastination, but I wanted to use it for life-extension rather than exhibition. So I think cryo with slicing might be best rather than plastination, which sounds kind of harsh (there is a lot of acetone, formaldehyde, stuff like that). I also think a UV laser instead of a meat-slicer would destroy fewer neuron connections (being about 1/4000th of a millimeter instead of about 1/10th).

Plastinated brains may even be revivable though, you never know. Perhaps the guys you see in exhibits will wander the earth again some day.
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queensblade
queensblade

June 6th, 2009, 10:49 pm #6

Maybe a carbon nanotube chainsaw with diamonoid teeth? For the new age Dr. Frankenstein.
I was into cryo, until i read about the cracking. They don't see it as a problem,
but it gives me heebie jeebies. All i can see is that frozen rose shattering,
after it's been dipped in liquid nitrogen. At this stage it's the only option for long term
storage. I hope something less destructive comes along in the near future.
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Joined: May 17th, 2009, 5:13 pm

June 7th, 2009, 4:10 pm #7

We definitely need some better tools. Slicing with a diamondoid chainsaw might be better than a laser. If you had a single strand of carbon nanotube, that's, what ten nanometers across? Total information loss would be down to 1:100000, which would be pretty good by comparison. On the other hand, if you had a technique that merely snapped the dendrites around a certain area, you could perhaps get the loss down to zero.

The slicing would definitely cut back on the cracking and freezing, if everything was done right. It would also be relatively easy to verify afterwards how good of a job was done in a particular case. The slices would be on slides, and it could be arranged to take them out of storage and photograph or scan them as long as their cryogenic temperature is maintained and they are held stiff.

Cracking happens due to cooling of different parts at different speeds. If you can eliminate that, you can eliminate the cracking problem. If we could distribute heat-conductive nanoparticles evenly throughout the brain prior to cooling you might not need to slice after all.

Another thought is that if you distributed nanotubes in the mix it might be sufficient to hold the material together despite the pressures that normally make it crack. This would give the heat time to escape without breaking the brain on its way out.

Cooling faster would tend to reduce brain damage from self-digestion and protect it from the toxicity of cryoprotectants. Ultimately I think the nanoparticle idea is probably something like what will lead to the first healthy mammal or person being brought back from cryosuspension, because they won't need the cracks "stitched" back together using nanomachinery.

Nanomachines are as different from nanoparticles as cars are from equivalent-sized boulders. The term "nanotech" is used for all kinds of things these days, so I try to distinguish. We use nanoparticles everyday now in everythiing from sunscreen to paint, so if you could find some that work for this cryonics stuff we might be routinely thawing and reviving people in just a few years. The brains with cracking will still have to wait quite a while longer, but I think we'll eventually be able to help them too.
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