X-Message-Number: 9189
From: Thomas Donaldson <>
Subject: Re: CryoNet #9185 - #9186
Date: Sun, 22 Feb 1998 20:32:31 -0800 (PST)

Hi guys!

Well, I never took the bet, for exactly that reason. 

If Mr Strout (going on Dr. Strout) wishes I can send him some interesting 
stuff from recent PERIASTRON articles. It's quite possible that we will 
see imminently (well, if imminence is measured in 30 year gulps) the ability
to repair lots of different kinds of brain damage. This would NOT be done
simply by attaching one end of a broken axon or dendrite to the other: we
already know that doesn't work. But cleverer ways already exist (after
all, brains do not have passive wiring like computers do).

I agree that loss of memory is a problem, and that given that memory is
ultimately stored in the connectivity of our neurons, we will want to work
out ways to sense what that connectivity used to be (if it no longer exists)
and then restore it. If Mr. Strout wants that restoration to take place
elsewhere, he still must sense it first. Sure, gross nerve tracts can be
worked out right now, but we want to work on a much finer scale. Doing CT
or PET scans does not look like it will give the resolution required. (This
was actually discussed in previous postings).

One question, which continues to puzzle me (neuroscientists seem not to
have gotten to it, but they will) is just how new synapses are created 
AND PERSIST long enough to form true long term memory. The persistence
is just as important as the creation; since brains are living, they will
like other living cells undergo constant breakdown and rebuilding. The
existence of a synaptic connection must imply other things, somewhere in
the cell, which keep it there for some time. (Yes, if we had an answer
to that we'd also have a clue to what connections were there before 
they were broken). The processes which keep a synapse need have no 
direct relation to memory at all, but they could be valuable clues, 
regardless. (Wherever you wanted to recreate a brain!). There are already
various facts about our connections which can serve as important clues,
but the more the better.

			Best and long long life to all,

				Thomas Donaldson

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