X-Message-Number: 9816 Date: Sat, 30 May 1998 11:00:57 -0400 From: Thomas Donaldson <> Subject: CryoNet #9802 - #9813 Hi to everyone! Well, once more for Mr. Clark (and since Bob Ettinger has gotten into this something for him too). Let's see here. My very first comment is that it simply isn't enough, when talking about how our brains might be changed by cryopreservation, to leave the matter so open as Ralph did. It is quite possible to test empirically to get an idea of just how much motion may occur. Naturally the kind of motion makes a big difference; that is a big problem. Neurons are close to one another, and there are many different kinds. Just by saying that things have been jostled around a bit, we still don't know whether the puzzle can be put back together. Survival of memory, which I believe is what we are really after, will require that we put back the puzzle to an as yet unknown degree of exactness. Not only that, but movement may involve rotation, plus the intrusion of other tissue into cracks. In one sense I agree with Ralph: I too am optimistic. But if we are going to talk about the motion of brain tissue and cells and cell parts during the freezing process, we should get some DATA first. I do not believe there is any general argument which would allow us to avoid that need for data. It simply isn't enough to talk generally about how we will be able to locate every atom and molecule. Since our memory very likely exists on a higher level than the molecular, we need to know how badly that higher level has been disrupted. And that will need more knowledge about brains. For instance, consider synapses. By some process as yet unknown, our memories may be stored in the "strength" (left undefined) of synapses. Fine. But does freezing with cryoprotectants disarrange the structures responsible for this storage? It is important here to know that synapses have tended to be more durable than the cell membranes themselves. That, to me, is much more pertinent information than any future ability to locate atoms and molecules precisely. Again, single synapses dislodgd from their neurons won't tell us a lot. However it turns out that neurons don't all use the same neuro- transmitters, and hence by examining the receptors on a synapse we can exclude some possible candidates for its original location, and list others. I'm not talking generally, I'm talking neuroscience. Bob discusses various points about the general physics of freezing. Yes, LARGE cracks do happen, and in that case it's clear that we know how to put them together. But I've not yet heard any detailed data about the fine, lower level cracks and how they behave in brain tissue. Do we get something sharp, or do you just get a collection of pieces which began by being distorted and partly frozen, and then froze completely. Brain tissue is a complex form of matter, which can't be modelled as if it were a uniform volume. If Ralph, or Bob, or anyone wants to do the experiments needed to get better models, then I'll happily help out. One major problem that I see is that our memories probably exist in the fine connectivity of our neurons. If the pieces don't retain their original shape, we can't use shape to fit them together. Yes, there are chemical clues that may help --- but that is neuroscience. In my original posting that started this off, I gave quite a number of questions which could be answered now or soon, though they would take lots of work. I hope that we get around to answering them, since they will take us away from the very general arguments with have dubious application to a discussion of just what happens. If we are going to model the behavior of brains when frozen, we need to get more parameters. It's simply not enough to make simple assumptions and decide on that basis that repair will likely be possible. A lot is going to depend on the traits of this complex form of matter we call our brain. As for Goldwater: too bad, one more. And just a little for Mr. Mazanec: I've already explained why I think cryonics won't go away. There will always be conditions which we don't know how to fix at any given time, though we can hope someday to learn how to fix them. My arguments here come simply from the fact that we will never totally control the Universe. I would even argue that we'll never totally understand it, but to fix anything we need control, not just understanding. And I've also explained the problems that will arise when we can reverse suspensions. Fine. This will mean that we can tell someone who has a currently incurable disease that he can be suspended for an indefinite time and hope for a cure. And that he will know that he can be revived at any time in the same dying condition he had before. The problem with "currently incurable diseases" is that most people will consider them to be similar to death: not just currently incurable, but something for which a cure is IMPOSSIBLE. Will they ever shake themselves loose from that idea? Incidentally, we're seeing yet one more case of the impossible cure slowly moving into possibility. There's been lots of work over the last few years aimed at repairing broken spinal cords, with significant advances in animals. Go back 25 years and tell doctors about this, and they would not have believed you. They would probably simply write you off as another crank. I believe that the main reason (though it has many byways modifications) for which most people will not consider cryonics is that when they do so they must consider their own death, which they don't want to do. And all their excuses for not thinking about cryonics come down to ways to avoid thinking about their death. Best to all, and long long life to all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9816