X-Message-Number: 3345
From: Brian Wowk <>
Date: Mon, 24 Oct 94 00:30:34 CDT
Subject: SCI.CRYONICS Brain scanning, reply to David Stodolsky

David Stodolsky:
> Unfortunately, I don't have Merkle's paper on hand, but I recall that
> the first step in the procedure was to "fix" the brain and embed it
> in a plastic cube, prior to processing. Since the fixation required
> does not need to consider revival of the brain, it is a significantly
> easier problem then that faced in cryonics. It completely eliminates
> potential freezing damage. 
        Yes, by trading freezing damage for autolysis (fixing takes 
time) and fixation damge, both of which are much worse than freezing 
> You may not consider a "fixed" brain as a safe form of storage, as
> compared to having multiple copies of brain backup information, but
> it is certainly more safe than a brain in cryonic suspension. So,
> I continue to maintain that Merkle's proposal is an alternative that
> is somewhat less demanding of *current* technological capabilities
> and has significantly weaker requirements in terms of continuous care
> by a social unit. 
        I agree that fixed brains are easier to store and maintain 
than frozen ones.  The question is, what are you storing?  It is far
from obvious that tissue fixation and storage at room temperature
will preserve the essentials of memory and identity.
        By the way, Ralph Merkle, to my knowledge, has never proposed
brain fixation as an alternative to cryonics.  Perhaps you are confusing
Ralph's paper with one in Medical Hypotheses several years earlier,
which Ralph references in his cryonics paper in that same journal?
Ralph's monograph (published by Xerox PARC) is entitled "Large Scale 
Analysis of Neural Structures," and is a proposal for a megaproject
to map the neural anatomy of a human brain for neuroscientific study.  
(I believe Keith Lynch posted the URL a couple of days ago.)  
This is NOT the same as storing or reading memory and identity for 
future revival.  As I said, it is not obvious that fixation preserves 
these things.  (In fact, it is not obvious that freezing does either.  
Just more likely.)
>Brian Wowk <> writes:
>>        The only thing that makes x-ray holography marginally possible
>>at 1keV is the low energy per photon.  However if you want to image  
>>anything larger than an insect, higher energies are required.  As energy
>>is increased, the cross section for coherent scattering drops, and the
>>energy per absorbed photon increases, escalating the required dose to
>>ridiculous (vaporizing) levels for something as large as a brain.
>What about just enough energy to image the depth of the cortical sheet?
        If you permit disassembly of the brain before imaging, many
things become possible.
>>         I reiterate: Nobody is ever going to use ionizing radiation to
>> "read out" the memories of an intact whole brain.
>You are imposing unnecessary requirements. Assume vaporization
>is permitted. Can the information be extracted under that condition,
>or does the vapor generated absorb most of the image beam?
        Are we going to talk about nuclear bombs in space again,
David? :) 
--- Brian Wowk

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