A great piece on the cryonics industry, with a focus on Alcor. Cryonics providers offer indefinite low-temperature storage for those who will die prior to the advent of effective rejuvenation therapies. This is the only shot at a longer life in the future available to those people, a demographic that may turn out to include all of us if things go poorly in medical research and advocacy over the next few decades. A cryopreserved individual has all the time in the world to wait for future restoration technologies to arise, as provided that the fine structure of the brain is maintained in the preservation process then the mind continues to exist, on hold:
In terms of the revival end of things, it's a long way off. [Alcor] isn't doing a whole lot of research there because it's too much of a cap on what we can do. There is a startup company that I can't really talk about that that's doing that, trying to grow tissues, grow organs. The whole field of regenerative medicine is really relevant to what we're doing. We benefit from a lot of other fields of research, like nanomedicine and the people trying to cryopreserve organs. They've actually managed to cryopreserve a rabbit kidney, keep it there for several months and then rewarm it, implant it in the rabbit and have it function. You can do it with all kinds of single tissues - it's very common now to cryopreserve corneas, sperm, eggs - there are dozens of tissue types that can be cryopreserved and then rewarmed. Going from a single tissue to a whole organ is much more difficult.
What we would imagine is that the brain would actually be repaired cell by cell, which is why we want to minimize the damage we do because there are a lot of neurons to be fixed. We do know that under good conditions we are preserving brains very well - we can look at vitrified brain tissue from animals under an electron microscope and it looks great. You can see the membranes are all intact, the neurons are all connected, it looks perfectly preserved.
Everything we know about personality tells us that it's stored in physical changes in the brain. Apart from very short term memory where the last few minutes is all electrical activity, anything longer than that is stored in changes in the neurotransmitter connections in the brain. That's what we're preserving under good circumstances. We're not just being speculative and taking a leap of faith. We've started a program of doing CT scans of our neuro patients. We can get really good readings of people's brains and see how we're doing.
It looks worse if we can't perfuse the brain [with cryoprotectants] and get ice crystal damage, but it doesn't mean it's destroyed. It's going to look bad to us, but in our view, we look at it like, the functional ability of the brain's been destroyed, but function is not really crucial. What really matters is that you're storing enough of the structure that some future technology can look at it and say "this membrane's been damaged really badly, but we know how to put it back together."