5 ms·

Plastination versus Cryonics

53 points by monort 11y ago

davidrusu 11y ago
It's important to realize cryonics/plastination research is not just for people who want to extend their lives. It's going to be a crucial component in long term space flight.
- listic 11y ago
  I am not convinced that long term space flight will be really interesting, at least before we radically extend our lifespan (you mean interstellar, right?). The space is just too big.
  - Symmetry 11y ago
    A Hohmann transfer even to Neptune is 40 years. In practice I'd expect it would be more like a decade using less efficient orbits but I hope that shows that even within the solar system there can be trips long enough that suspension would be an asset.
anti-shill 11y ago
preserving information is key...if plastination preserves memory, it is worthwhile.
geographomics 11y ago
Preserving the connectome is probably insufficient for full restoration. Even if you could record the entire structure of the brain at the synaptic level, you're still missing the functional states of the neurons and glial cells that it is composed of. It would be like trying to reconstruct a piece of software solely from its call graph.
Udo 11y ago
> current plastination techniques sufficing to create connectomes, but what does it miss? I'm not worried about neurotransmitter levels or electrical activity, there are enough events during a normal lifetime where these can be severely compromised without any long term effects. What I am worried about, though, is the fine structure of "custom" proteins - meaning proteins that have been specifically generated by the brain to modulate the activity of one or more very specific neurons. It's not unreasonable to suspect that these serve an important role in long term memory formation and function. I strongly suspect digitizing the connectome by itself may not be enough in the same way that saving the structure of an artificial neural network without preserving info about any weights, activation functions, and other parameters is not enough to reproduce the network later. > by copying the digital data to many archives and formats online and offline. No such option is available to a cryonics brain unless it abandons cryonics entirely How you judge this depends on what you're trying to achieve with cryonics. In theory, a destructive scan of a cryo-preserved brain should yield more and better data than that of a plastinated one. The question becomes: do we need that additional data or not? I'd like cryonics to preserve brains until it becomes clear how to scan them adequately. By comparison, cryonic preservation is a relatively gentle process, whereas plastination imposes some heavy chemical changes on the brain to the point where it's entirely likely that too much information could be lost. The promise of cryonics lies not in a biological resurrection at a later date, but in giving researchers enough time to figure out how to actually do an upload. It may well turn out that plastinated remains are a sufficient data source, but contrast that with cryonics where much fewer doubts about the preservation of the necessary information exist. Of course, cryonics is beyond problematic - it requires constant and costly upkeep. And more importantly, just a few days of political, economical, or technological instability can easily wipe out every cryo-preserved brain in existence. So it's clear this can't be a solution for the next few hundreds or years. It's a solution for the next few decades at best (until the first provider goes bankrupt). The options, in a word, all suck.
- Neslit 11y ago
  >cryonics [has] much fewer doubts about the preservation of the necessary information Could you say why you think this? Were you convinced by the experiments done by the Cryonics Institute or Alcor? I haven't been able to contact a disinterested neuroscientist willing to take a serious look at that research. >just a few days of political, economical, or technological instability can easily wipe out every cryo-preserved brain in existence Political, maybe, if the the legal status of patients changes so that they are required to be thawed. But why economical or technological? I think I read somewhere that it would take like a month or something for the liquid nitrogen to evaporate enough for the patients to thaw.
  - Udo 11y ago
    > Could you say why you think this? During my time as a medical research minion I did some work on preserving tissue samples and even whole organs, including plastination and similar resin casts. What you need to be aware of is that, while the finished specimen look very good and life-like, they are radically altered on a biochemical level. All the water and lipids get replaced by resin. That requires soaking them in formaldehyde, acetone, and other chemicals before resin can even be applied. This process absolutely destroys proteins, in fact it relies on that. Also, the whole process takes days to complete, and during that time bio matter is actually being washed out and the whole structure is in motion. There is absolutely no question that information is lost here, in droves. If you believe plastination has a decent chance of preserving people's minds, you're operating under the assumption that the connectome itself will yield enough data for an upload. Compared to that, freezing is, well freezing. Molecular motion almost ceases, so the most important aspect to gauge information loss in cryonics is what happens to the brain until it's finally cooled down. There are three main problems here. The first is the formation and shape of ice crystals which can (and do) destroy cells. This is a bit more relevant to in-vivo reanimation enthusiasts, because the physical shearing should probably be algorithmically correctable in a scan scenario. The second is the effect of the cryo fluid they pump into patients to prevent said ice crystals from forming, because it's also toxic to proteins. It's not as invasive as plastination, but it's still pretty bad. The third aspect is the time span from asystole to the halting of information loss. This might be a problem, but since current research indicates that a lot of ischemic brain damage is actually a cascade triggered by re-perfusion, there is cause for the assumption that anything up to a few hours might actually be fine. > Were you convinced by the experiments done by the Cryonics Institute or Alcor? I have to admit to only a passing knowledge of their in-house research efforts. Alcor's that is, I know next to nothing about CI. The problem is, they - nor anyone else for that matter - are not in a position to make any substantive claims about information fidelity beyond the continuing efforts to preserve the brain as faithfully as possible. A lot of their statements seem to focus on future viability of the tissue, and options for biological reanimation - but these are things I have no interest in (because I think it's both unrealistic and a bad deal). In fact, the last time I visited Alcor's site I couldn't find any reference to uploading at all, maybe I just missed it though. > Political, maybe, if the the legal status of patients changes so that they are required to be thawed. Yes, I agree. It's a massive taboo, ask any random person on the street and they'll be horrified. It's not difficult to imagine neuropreservation might get outlawed as soon as it looks like it might actually be feasible. In fact, we're seeing the same thing happening now with AGI. One can only imagine the public outcry involving bringing conserved brains back to life will be magnitudes larger than whatever will happen in respect to AGI soon. > But why economical or technological? By definition, cryonics companies have to operate on the fringe. That makes them especially vulnerable to disruption from relatively minor events. But even if they were as stable as, say a major bank: well, those fail, too. And if they're not going bankrupt, one might imagine a power outage lasting for months. Or some other infrastructure catastrophe that results in these companies being unable or unwilling to maintain services. Us western countries are kind of operating under the assumption that we're stable and eternal, which is an illusion. That's why I said it's a solution for the next decades at best. During that time, if we really want to put resources behind it, we could theoretically figure out a destructive scanning -> uploading workflow (simulation can come later in principle). But if we're talking about biological reanimation... there is not even a tenuous time frame imaginable. We could easily talk hundreds of years until our nano tech is sufficiently advanced. And that's too long for two fragile companies to keep afloat in the face of economic crises, religious and cultural disapproval, incompetence and malice, accidents, disasters, and world events - any single one of which can wipe everything out.

53 points by monort 11y ago

It's important to realize cryonics/plastination research is not just for people who want to extend their lives. It's going to be a crucial component in long term space flight.

listic 11y ago
I am not convinced that long term space flight will be really interesting, at least before we radically extend our lifespan (you mean interstellar, right?). The space is just too big.
- Symmetry 11y ago
  A Hohmann transfer even to Neptune is 40 years. In practice I'd expect it would be more like a decade using less efficient orbits but I hope that shows that even within the solar system there can be trips long enough that suspension would be an asset.

anti-shill 11y ago

preserving information is key...if plastination preserves memory, it is worthwhile.

geographomics 11y ago

Preserving the connectome is probably insufficient for full restoration. Even if you could record the entire structure of the brain at the synaptic level, you're still missing the functional states of the neurons and glial cells that it is composed of. It would be like trying to reconstruct a piece of software solely from its call graph.

Udo 11y ago

> current plastination techniques sufficing to create connectomes, but what does it miss? I'm not worried about neurotransmitter levels or electrical activity, there are enough events during a normal lifetime where these can be severely compromised without any long term effects. What I am worried about, though, is the fine structure of "custom" proteins - meaning proteins that have been specifically generated by the brain to modulate the activity of one or more very specific neurons. It's not unreasonable to suspect that these serve an important role in long term memory formation and function. I strongly suspect digitizing the connectome by itself may not be enough in the same way that saving the structure of an artificial neural network without preserving info about any weights, activation functions, and other parameters is not enough to reproduce the network later. > by copying the digital data to many archives and formats online and offline. No such option is available to a cryonics brain unless it abandons cryonics entirely How you judge this depends on what you're trying to achieve with cryonics. In theory, a destructive scan of a cryo-preserved brain should yield more and better data than that of a plastinated one. The question becomes: do we need that additional data or not? I'd like cryonics to preserve brains until it becomes clear how to scan them adequately. By comparison, cryonic preservation is a relatively gentle process, whereas plastination imposes some heavy chemical changes on the brain to the point where it's entirely likely that too much information could be lost. The promise of cryonics lies not in a biological resurrection at a later date, but in giving researchers enough time to figure out how to actually do an upload. It may well turn out that plastinated remains are a sufficient data source, but contrast that with cryonics where much fewer doubts about the preservation of the necessary information exist. Of course, cryonics is beyond problematic - it requires constant and costly upkeep. And more importantly, just a few days of political, economical, or technological instability can easily wipe out every cryo-preserved brain in existence. So it's clear this can't be a solution for the next few hundreds or years. It's a solution for the next few decades at best (until the first provider goes bankrupt). The options, in a word, all suck.

Neslit 11y ago
>cryonics [has] much fewer doubts about the preservation of the necessary information Could you say why you think this? Were you convinced by the experiments done by the Cryonics Institute or Alcor? I haven't been able to contact a disinterested neuroscientist willing to take a serious look at that research. >just a few days of political, economical, or technological instability can easily wipe out every cryo-preserved brain in existence Political, maybe, if the the legal status of patients changes so that they are required to be thawed. But why economical or technological? I think I read somewhere that it would take like a month or something for the liquid nitrogen to evaporate enough for the patients to thaw.
- Udo 11y ago
  > Could you say why you think this? During my time as a medical research minion I did some work on preserving tissue samples and even whole organs, including plastination and similar resin casts. What you need to be aware of is that, while the finished specimen look very good and life-like, they are radically altered on a biochemical level. All the water and lipids get replaced by resin. That requires soaking them in formaldehyde, acetone, and other chemicals before resin can even be applied. This process absolutely destroys proteins, in fact it relies on that. Also, the whole process takes days to complete, and during that time bio matter is actually being washed out and the whole structure is in motion. There is absolutely no question that information is lost here, in droves. If you believe plastination has a decent chance of preserving people's minds, you're operating under the assumption that the connectome itself will yield enough data for an upload. Compared to that, freezing is, well freezing. Molecular motion almost ceases, so the most important aspect to gauge information loss in cryonics is what happens to the brain until it's finally cooled down. There are three main problems here. The first is the formation and shape of ice crystals which can (and do) destroy cells. This is a bit more relevant to in-vivo reanimation enthusiasts, because the physical shearing should probably be algorithmically correctable in a scan scenario. The second is the effect of the cryo fluid they pump into patients to prevent said ice crystals from forming, because it's also toxic to proteins. It's not as invasive as plastination, but it's still pretty bad. The third aspect is the time span from asystole to the halting of information loss. This might be a problem, but since current research indicates that a lot of ischemic brain damage is actually a cascade triggered by re-perfusion, there is cause for the assumption that anything up to a few hours might actually be fine. > Were you convinced by the experiments done by the Cryonics Institute or Alcor? I have to admit to only a passing knowledge of their in-house research efforts. Alcor's that is, I know next to nothing about CI. The problem is, they - nor anyone else for that matter - are not in a position to make any substantive claims about information fidelity beyond the continuing efforts to preserve the brain as faithfully as possible. A lot of their statements seem to focus on future viability of the tissue, and options for biological reanimation - but these are things I have no interest in (because I think it's both unrealistic and a bad deal). In fact, the last time I visited Alcor's site I couldn't find any reference to uploading at all, maybe I just missed it though. > Political, maybe, if the the legal status of patients changes so that they are required to be thawed. Yes, I agree. It's a massive taboo, ask any random person on the street and they'll be horrified. It's not difficult to imagine neuropreservation might get outlawed as soon as it looks like it might actually be feasible. In fact, we're seeing the same thing happening now with AGI. One can only imagine the public outcry involving bringing conserved brains back to life will be magnitudes larger than whatever will happen in respect to AGI soon. > But why economical or technological? By definition, cryonics companies have to operate on the fringe. That makes them especially vulnerable to disruption from relatively minor events. But even if they were as stable as, say a major bank: well, those fail, too. And if they're not going bankrupt, one might imagine a power outage lasting for months. Or some other infrastructure catastrophe that results in these companies being unable or unwilling to maintain services. Us western countries are kind of operating under the assumption that we're stable and eternal, which is an illusion. That's why I said it's a solution for the next decades at best. During that time, if we really want to put resources behind it, we could theoretically figure out a destructive scanning -> uploading workflow (simulation can come later in principle). But if we're talking about biological reanimation... there is not even a tenuous time frame imaginable. We could easily talk hundreds of years until our nano tech is sufficiently advanced. And that's too long for two fragile companies to keep afloat in the face of economic crises, religious and cultural disapproval, incompetence and malice, accidents, disasters, and world events - any single one of which can wipe everything out.