Re: Cryonics and information theory

From: S.J. Van Sickle (sjvan@csd.uwm.edu)
Date: Tue Jul 08 2003 - 00:07:26 MDT

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    On Mon, 2003-07-07 at 18:27, Eliezer S. Yudkowsky wrote:

    >>If dendrites and axons retract into the cell body within half an hour
    > >>after the neuron has been starved of oxygen (!!!),
    > >
    > > ### This is not true.
    >
    > Maybe I've got it wrong. What's the correct time?

    Well, as an extreme example:

    http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11455721&dopt=Abstractûœ

    apparently undamaged axons were detected immunohistochemically out to 168
    hours (7 days) at room temperature. Whether these are enough undamaged
    axons, whether the damaged axons retained sufficient clues to their
    original structure, and whether other necessary structures remain
    inferrable for reconstruction of a person are open questions.

    This is likely near the upper limit. I have seen reports of more complete
    survival of 6 to 24 hours. After about 18 hours the capillary bed and
    blood brain barrier break down sufficiently that it becomes difficult to
    impossible to perfuse cryoprotectants effectively, at which point the
    bucket method starts looking not so bad.

    steve van sickle



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