X-Message-Number: 11621 From: Thomas Donaldson <> Subject: memory preservation in cryonic suspension Date: Mon, 26 Apr 1999 23:17:18 +1000 (EST) To Michael Soloviev: Your brain researcher is very likely quite wrong about preservation of long term memory, though he may still be correct about short term memory. In short, freezing will certainly stop any activity of the neurons, and that activity is what produces SHORT TERM memory. That is, about 5 minutes or possibly up to a few hours. There is a very simple proof of this which deserves to be widely known. In the 1950's, Audrey Smith, a British cryobiologist, cooled animals down to 10 degrees C or so and then brought them back up. This treatment creates an animal which LOOKS dead, but of course no one now would claim it was. And it also abolishes all electrical activity and most chemical activity in the brain of the animal. Her papers and book discuss this, though now they are old and may not be in the latest indexes. HOWEVER, when these animals are heated up again it turns out that they retain most of their memories. That is, electrical activity does not sustain long term memory. Since chemical reactions also decrease at low temperatures the strong suggestion is that long term memory does not require ONGOING chemical reactions. One of the really interesting things that have happened when we look closely at how brains operate is the discovery of several quite different kinds of memory. Possibly the scientists whose opinions you describe meant only what we would now call short term memory (in fact, it may be even more restricted). Also, with current suspension methods, there is a serious possibility (but now only a possibility and not a certainty) that some suspended people will have their memories destroyed not simply because of low temperature but because of the destruction caused by that freezing. The concern about the effect of freezing is real, even though the account you give of these scientists' opinions may be wrong. (Yes, there is now ongoing research into "another kind of freezing", vitrification; and there are already substantial experimental reasons to believe that VITRIFICATION of our brains would preserve their memory). Best and long long life, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=11621