[ExI] Nice Article on Brain Preservation

[Anders Sandberg]

On 18/09/2012 16:05, John Clark wrote:
> True, all the information on how to make an egg is there in the 
> scrambled eggs but that does no good because I don't think even 
> Nanotechnology can get that information out and figure out how to 
> unscramble an egg. The egg has undergone turbulence and that means 
> tiny changes in initial conditions have led to huge changes in 
> outcome, we don't want that happening to brains. So the big question 
> is, does the brain preservation method cause turbulence? I could very 
> well be wrong because I'm no expert but my intuition says that plastic 
> infusion is less likely to produce turbulence than freezing.

I understand what you mean, although turbulence is probably not the best 
word here. What sensitive dependence on initial conditions (chaos) does 
is to make noise more powerful, randomizing parts of a system. Noise 
that just moves the system away from the original state is not a problem 
itself. The problem is the noise that makes it uncertain which original 
state the system had.

What kind of noise do we expect to see in freezing or plastination? In 
both there is the noise from dying. In freezing there is biochemical 
change and physical change due to the freezing process, in preservation 
there is the same due to the fixation, and then some chemical reactions 
during storage.

  * Freezing did cause a mess due to crystal formation and cracking, and
    is still mechanically a bit nasty, but I don't think (cryo-gurus
    please chime in) it causes regions to scramble. They just turn to
    puzzles.
  * The biochemical changes of both processes are hard to judge, but
    this is where I would be most worried: the brain is dependent on a
    lot of biochemical states that might only partly survive either
    treatment. This is where I really would like to know how much
    happens in a synapse, in particular to whether receptors remain
    bound to membranes and what G proteins do.
  * In freezing mobility of stuff goes down a lot quickly, while I get
    the impression the fixation is a bit slower. Then there is the
    problem of chemical change in fixed tissue: again I don't know if
    anything diffuses much, but that is worth watching for.

Not sure what the take home message is, beyond more research is needed 
(or, if it has been done, more dissemination needed).

-- 
Anders Sandberg,
Future of Humanity Institute
Oxford Martin School
Faculty of Philosophy
Oxford University

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20120918/e40eb3fe/attachment.html>