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> Small mammal organs have been successfully cryopreserved and thawed, and remained functional Wow, nice rhetorical dodge there. No one cares too much if smal

by evgen 9y ago

> Small mammal organs have been successfully cryopreserved and thawed, and remained functional Wow, nice rhetorical dodge there. No one cares too much if small mammal 'organs' have been successfully cryopreserved and revived because we can replace your kidney and you are still you. Tell me about the small mammal BRAINS that you have cryopreserved and revived with any evidence of retention of memories or prior training. Tell me about any nervous systems at all which you have successfully preserved and revived. Doesn't have to be a mammal, I would settle for an insect. Tell me about those please. Until you can do this you are just selling another version of snake oil.

ggreer 9y ago
> Tell me about the small mammal BRAINS that you have cryopreserved and revived with any evidence of retention of memories or prior training. Nobody has revived a small mammal brain because unlike kidneys, we don't yet have the technology to transplant brains. Brains are easier to perfuse with cryoprotectant than kidneys, so they tend to be preserved better. Cryoprotectants seem to be tolerated well by neurons. It is currently possible to cryopreserve & thaw rat hippocampal slices while keeping structure intact and over 90% of cells viable: http://www.21cm.com/pdfs/hippo_published.pdf http://www.21cm.com/pdfs/hippo_published.pdf > Tell me about any nervous systems at all which you have successfully preserved and revived. Doesn't have to be a mammal, I would settle for an insect. Tell me about those please. People have cryopreserved & thawed nematodes with an 84% survival rate: https://www.ncbi.nlm.nih.gov/pubmed/23995406 https://www.ncbi.nlm.nih.gov/pubmed/23995406 The cryopreservation of many kinds of insects (usually in larval or embryonic form) is doable as well. Some of these organisms have thousands of neurons. The whole point of cryonics is to take advantage of the difference in technology required for preservation versus revival. Saying, "Cryonics is snake oil because revival doesn't work yet." is demanding evidence that can't yet exist even in the case that cryonics works.

by evgen 9y ago

ggreer 9y ago

> Tell me about the small mammal BRAINS that you have cryopreserved and revived with any evidence of retention of memories or prior training. Nobody has revived a small mammal brain because unlike kidneys, we don't yet have the technology to transplant brains. Brains are easier to perfuse with cryoprotectant than kidneys, so they tend to be preserved better. Cryoprotectants seem to be tolerated well by neurons. It is currently possible to cryopreserve & thaw rat hippocampal slices while keeping structure intact and over 90% of cells viable: http://www.21cm.com/pdfs/hippo_published.pdf http://www.21cm.com/pdfs/hippo_published.pdf > Tell me about any nervous systems at all which you have successfully preserved and revived. Doesn't have to be a mammal, I would settle for an insect. Tell me about those please. People have cryopreserved & thawed nematodes with an 84% survival rate: https://www.ncbi.nlm.nih.gov/pubmed/23995406 https://www.ncbi.nlm.nih.gov/pubmed/23995406 The cryopreservation of many kinds of insects (usually in larval or embryonic form) is doable as well. Some of these organisms have thousands of neurons. The whole point of cryonics is to take advantage of the difference in technology required for preservation versus revival. Saying, "Cryonics is snake oil because revival doesn't work yet." is demanding evidence that can't yet exist even in the case that cryonics works.