Scientist Steven Austad is well known in the field of aging research. For the past few years he has penned a column for a Texas paper - the sort of public engagement that I'd like to see more researchers undertake on a regular basis. Here he writes on the topic of cryonics, which is something else I'd like to see more researchers do on a regular basis, even if they clearly need to better investigate the topic first:
Cryonics is the idea - or more precisely, the hope - that by freezing your body after death, future scientists will be able to bring that body back to life. Why future scientists would want to do this isn't exactly clear. Maybe there will be no more pressing problems in the future than bringing dead people back to life. Anyway, assuming they wanted to for some reason, the real hope is not that only your body would be brought back to life, but that you would be brought back to life. Something like awakening after surgery.
Cryonics embodies a rather touching faith in scientific progress. Or maybe it embodies only an exceptional fear of death. In either case, it raises some interesting philosophical questions. What would it take for that newly re-animated body to still be "you?" With a little tweaking of existing technology, we could create a genetically identical copy of you as we've already done in mice, dogs, and a number of other species, by cloning a cell from your current body. But that wouldn't really be you, because it wouldn't have your memories or experiences.
Memories are the key. Thus, the frozen head. As long as your brain still contains your memories, your re-animated head could be thought of as you. As for the rest of your body, any science sophisticated enough to bring your head back to life should no doubt be able to give you the body you want. I'll have to think about whose body I'd like.
Besides, keeping only your head saves money. Cryonics is not cheap. Prices I've seen range from about $30,000 for a budget deal to several hundred thousand, not including the currently unknown cost of re-animating you and putting a body to that head. Long lines of freezers packed with bodies like so many popsicles uses a lot of expensive liquid nitrogen and takes up a lot of space, for who knows how many years? Freezers full of hat box-size containers are comparatively economical and good for the profit margin.
There do seem to be some formidable scientific barriers though, even if you assume that re-growing a body is feasible. For one thing, no one has brought something even as simple as a single cell back from being dead, not that I'm sure how much effort has been put into doing so. Another issue is that our memories are thought to be a product of the number and strength of very delicate electrical connections among our billions of brain cells. Memory can be seriously disrupted by something as simple as a blow to the head. So preserving those things through a complete cessation of all brain electrical activity and the inevitable postmortem damage to brain cells seems more than a little far-fetched. Also, if you died of a stroke or dementia, sorry, you're out of luck. Those critical memory centers were destroyed even before you died.
Whatever your opinion of cryonics, to my mind the head thing needs rethinking. The important thing obviously is preservation of the brain. So why not freeze just the brain rather than the whole head? If science proceeds to the point where they can re-grow a complete body, surely it will be able to give me a better head.
Cryonics is a process of low-temperature vitrification rather than freezing these days, which is an important distinction to make. Frozen tissue is damaged by ice crystal formation, vitrified tissue is not to any significant degree. Vitrified cells and even organs in recent years have in fact been restored from this form of low-temperature storage. There is also good evidence to show that the fine structures of neurons that store the data of memory are well preserved by vitrification.
Most people who undertake cryonics are of modest means, and cryonics providers are not run as for-profit companies at this time. The cost of cryonics is generally managed through a life insurance policy. With enough forethought a tiny monthly payment puts you in good shape for a future cryopreservation - and it is certainly the case that organizing your own end of life choices requires planning ahead. Last minute decisions tend to run poorly.
Why preserve the whole head? Because trying to do otherwise is more likely to result in damage to the brain and will raise costs by requiring more skill and training for paramedical staff. The cryopreservation process has to happen fairly rapidly and involves perfusion of cryoprotectant chemicals. Adding an additional major operation to that process, while at the same time removing a layer of protection from the brain, doesn't sound like a great plan to me.