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

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