X-Message-Number: 12389 From: Thomas Donaldson <> Subject: loss of memory Date: Thu, 9 Sep 1999 21:54:30 +1000 (EST) Hi! Since John de Rivaz has published your questions on Cryonet, and partially answered them, I thought I'd add a bit myself. You may or may not be aware that taking someone down to 0 C but NOT freezing them will not affect their memory. This has actually been experimentally proven with animals, even if it was done in the 1950's. Audrey Smith, a prominent British cryobiologist of that time, looked at whether taking several species of small animals down to 0 C but without freezing would affect their memory. Animals treated in this way look quite dead. However it turned out that they recovered their memory after being warmed up. At the time this was seen as decisive evidence that our memories did not depend on persistence of activity in our brain. (Brains of these animals were electrically silent, as you can guess). Right now there is lots of work going on by cryonicists to cut down the damage caused by taking an animal (or a person) down to the LN2 temperatures required. One process now under investigation involves not freezing but using cryoprotectants which produce a glass at similarly low temperatures. This cuts down on damage to a very great extent. Some cryonicists believe that IF we can fund the research, we can produce cryonic suspensions for which memories PROVABLY persist in about 10 years. That won't be the whole of the problem, unfortunately. Cryonics is a form of emergency medicine, and will probably remain that way indefinitely; this means that the conditions of a particular suspension need not be the same as one carried out with full warning and no legal or other problems. The problem there is that we may be forced to use methods which aren't the best at the time ... the only alternative is to give up completely. So a definition of death which specifies that you are dead if the information in your brain has been destroyed remains important. Just what conditions will and will not destroy that information in particular cases remains unknown. It can be worked on, but most living cryonicists would (for NOW) most support research on preserving it under the best possible conditions ... those to which I referred above by saying that we have a chance of solving their problems in 10 years. We still feel an obligation to work on the other cases, too, of course. And you will note from my explanation that I (and any other cryonicist!) prefer to take the cautious route of keeping anyone for whom we DID NOT KNOW that information had been preserved rather than simply destroying them because we happened at the time not to know how to fix them. We may well find that we've kept in preservation some patients for whom we can someday prove that they're actually dead; but to simply ASSUME someone is dead because we happen not to be able to tell strikes me and other cryonicists as the height of inhumanity. Best wishes, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=12389