X-Message-Number: 10410
Date: Fri, 11 Sep 1998 09:53:50 -0400
From: Thomas Donaldson <>
Subject: CryoNet #10406 - #10408

HI everyone!

I will assume that the micrographs produced by 21st Century Medicine
and others looking at the brains of animals cryonically suspended were
reasonably competent.

However there is another issue and it is very important and absolutely
MUST NOT be forgotten. Platt himself described the results as looking
fine on gross examination, while the electron microscope showed lots of

It is now 1998, and whatever else has happened in neuroscience since
the 1970's, it is now EXTREMELY likely that by one means or another
our memories are shown (I won't say "encoded", since that introduces a
bias I don't want) in the connections between our neurons. Put bluntly,
this means that our memories may well continue to exist despite a 
great deal of damage to the individual neurons. The kind of damage
which might destroy memory would be extensive loss of this connectivity,
and connectivity occurs at a higher level than most cell functions.
It also occurs on a level higher than that of molecules or atoms --
much higher.

Such things as the biochemicals present in the damaged cells can be
quite relevant, if we want to RECOVER connectivity which has somehow
been broken. Electron micrographs aren't noted, unfortunately, for
their ability to identify the biochemicals present and their 
distribution in the neurons and glial cells of our brain (or anywhere
else, either). There is, however, quite extensive knowledge of how
to produce stains which show up the presence of many different 
chemicals, individually. One major method for doing so is to use
immune reactions to them to produce antibodies (say, you get a rat
to produce an immune reaction to a human brain chemical). These
antibodies are then chemically linked to a suitable fluorescent 
(or radioactive, or colored) chemical and the brain area is then 
soaked in them. Presto! You now know the distribution of the particular
biochemical you wanted to study.

A recent issue of PERIASTRON described how this method could distinguish
between all the different interneurons (put simply, our brain cortex 
consists of pyramidal cells and interneurons --- its actually much more
complex, but basically this is the situation) in our brain cortex. Since
interneurons also have characteristic areas on the pyramidal cells to
which they connect, this tells us where connections may have been.

There are also older methods which simply use particular chemicals. These
can show the presence of synapses (or their absence).

Clearly some special methods would then be needed to somehow revive,
repair, or replace (WITH their connections) the damaged neurons, and 
probably the damaged glial cells too. (Glial cells generally provide 
lots of metabolic support for the nerve cells, but don't directly 
contain information). That's where nanotechnology of some kind comes
into the picture. 

This does not prove that our memories will necessarily survive. We won't
have any idea of this until we do much more study. However it does say 

It also says that repairing brains even on a molecular scale, while it
may sound impressive, misses the MAJOR KIND OF DAMAGE completely. We
can restore ourselves, with our memories, despite many rearrangements
within each of our neurons --- such rearrangements are simply irrelevant
to our memories, though within wide limits they do affect the survival of
a particular neuron. (ie. just where the mitochondria may be isn't of
much importance at all, so long as there ARE enough mitochondria working).

So here are some thoughts about how brains work, and how that is VERY
relevant to cryonics.

			Best and long long life to all,

				Thomas Donaldson

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