Do you think that the cryopreservation process itself damages the brain cells enough to destroy the mind?
No. Cryopreserving some tissues is common today. Organs from mammals have already been cryopreserved and transplanted. Electron micrographs of cryopreserved brain tissue show almost no degradation. There is an issue with microfractures, but the amount of information destroyed by them is minimal. The fractures are very few and translate tissue along a plane by a few microns. The other problem is ischemic injury. This is mitigated by having standby procedures and ID tags with instructions on how to begin cooling the body. Brain cells don’t immediately die when deprived of oxygen, but they do start an ischemic cascade that can’t be prevented currently. The cascade takes several hours at normal body temperature, and is drastically extended if the body is brought close to freezing.
Do you think that long-term storage at low temperatures damages the brain enough to destroy the mind?
No. Biochemistry is basically stopped at 77K. The only degradation occurs from free radicals caused by cosmic rays. About 0.3 milliSieverts is absorbed each year. The LD50 for acute radiation poisoning is 3-4 Sieverts with current medicine. That’s at least 10,000 years of cosmic rays. The human body itself contains some radioactive isotopes, but if you do the math it’s still well over 1,000 years before radiation poisoning is an issue.
Do you think that no future technology will be able to recover the mind from a cryopreserved brain?
No. See my comment about microtomes, microscopes, and brain emulation. That’s just using slightly improved technology. A superintelligence with molecular nanotechnology certainly wouldn’t have a problem reviving a corpsicle.
Whew, that was a lot of text and links. Once you said the discussion was over I couldn’t resist.
Nice term. I hadn’t heard it before. I read now that I am evidently supposed to find the term offensively pejorative. But I’ll take tongue in cheek humour over dignity any day of the week.
I would like to check something. I naively imagine* that if you freeze a person cryonics-style, no damage is done to their brain immediately. So that if you froze a person that was alive, and then un-thawed them 5 minutes after you froze them, they’d wake up virtually the same—alive and unharmed. Is this true?
*This idea is based on stories about children frozen in lakes and optimism.
“Children frozen in lakes” are not frozen, only hypothermic. If you actually get ice in your brain cells you die.
“Freezing” a person “cryonics-style” begins with drainging all the blood from their head, and the process takes more than a few minutes. So it is pretty much guaranteed to cause severe brain damage or death if you do it to a live person. Which means that it would not be legal, even if somebody had done that experiment they could not publish it.
I don’t think so. Vitrification and the chemicals used are poisonous, but fixing the toxic damage is presumed to be one of the easier steps in reviving someone’s vitrified brain.
This might be true for some definition of freezing a person but not with the protocols currently used by Alcor and CI.
Burden of proof? Did you look at the giant amount of information already written on cryonics?
Fine, here are my answers to my own questions.
No. Cryopreserving some tissues is common today. Organs from mammals have already been cryopreserved and transplanted. Electron micrographs of cryopreserved brain tissue show almost no degradation. There is an issue with microfractures, but the amount of information destroyed by them is minimal. The fractures are very few and translate tissue along a plane by a few microns. The other problem is ischemic injury. This is mitigated by having standby procedures and ID tags with instructions on how to begin cooling the body. Brain cells don’t immediately die when deprived of oxygen, but they do start an ischemic cascade that can’t be prevented currently. The cascade takes several hours at normal body temperature, and is drastically extended if the body is brought close to freezing.
No. Biochemistry is basically stopped at 77K. The only degradation occurs from free radicals caused by cosmic rays. About 0.3 milliSieverts is absorbed each year. The LD50 for acute radiation poisoning is 3-4 Sieverts with current medicine. That’s at least 10,000 years of cosmic rays. The human body itself contains some radioactive isotopes, but if you do the math it’s still well over 1,000 years before radiation poisoning is an issue.
No. See my comment about microtomes, microscopes, and brain emulation. That’s just using slightly improved technology. A superintelligence with molecular nanotechnology certainly wouldn’t have a problem reviving a corpsicle.
Whew, that was a lot of text and links. Once you said the discussion was over I couldn’t resist.
Nice term. I hadn’t heard it before. I read now that I am evidently supposed to find the term offensively pejorative. But I’ll take tongue in cheek humour over dignity any day of the week.
I guess as with other epithets, it’s acceptable for members of the slighted group to use the term amongst themselves. :)
There’s a minimum budget Sci. Fic. movie for you right there!
“What up Corpsicle?”
“Me! Mwahahahaha!”
I would like to check something. I naively imagine* that if you freeze a person cryonics-style, no damage is done to their brain immediately. So that if you froze a person that was alive, and then un-thawed them 5 minutes after you froze them, they’d wake up virtually the same—alive and unharmed. Is this true?
*This idea is based on stories about children frozen in lakes and optimism.
“Children frozen in lakes” are not frozen, only hypothermic. If you actually get ice in your brain cells you die.
“Freezing” a person “cryonics-style” begins with drainging all the blood from their head, and the process takes more than a few minutes. So it is pretty much guaranteed to cause severe brain damage or death if you do it to a live person. Which means that it would not be legal, even if somebody had done that experiment they could not publish it.
I don’t think so. Vitrification and the chemicals used are poisonous, but fixing the toxic damage is presumed to be one of the easier steps in reviving someone’s vitrified brain.
This might be true for some definition of freezing a person but not with the protocols currently used by Alcor and CI.