X-Message-Number: 12583
Date: Sat, 16 Oct 1999 14:24:10 -0700
From: Jeff Davis <>
Subject: Re: New laser method reveals high-density information storage

 In Message #12573,
 Eugene Leitl <> writes:

>I guess I don't have to explain anybody what this means in regards to
>the impact of the freezing damage -- a yet another high watermark in
>the trend that nature's gadgets are cleverer than we thought has been
>reached.

I don't know about anyone else, but I have always been ready to be
surprised at how clever "nature's gadgets" turn out to be.  But in this
case, I don't see a greater cleverness than anticipated.

From the paper gene cited:

>single synapses may undergo long-term depression
>and each single synapse could be used to store information
>separately from its neighbour.

What this means is that each synapse is a single bit, with long-term
depression(LTD) as the off/zero state and long-term potentiation(LTP) as
the on/one state.  Exactly as I expected.  Which is not me bragging, but
rather because "one bit per synapse" seems logical, parsimonious, elegant,
and efficient, and I would expect anyone to be able to make this guess on
the very first try.   

>It thus appears simply not prudent to adhere to the more optimistic
>scenarios ("manipulation at molecular scale can repair any type of
>damage"). 

Anything and everything, relevant or otherwise leads to the same conclusion
with you: optimism is unwarranted.  Sorry, gene, but you bring a
prejudicial pessimism to your reading, analysis and discussion.  It's a
foregone conclusion for you, as it is for the other members of the
Platt/Wakfer/Darwin school.  The paper you cite doesn't bring anything new
to the discussion--the idea that each synapse is a separate and independent
bit is neither original nor unexpected--it merely announces the first
achievement of a  technique to confirm these expectations.  Better tools to
turn good guesses into established facts.  Great.

The conclusion reached by my analysis, that the success of cryonics is a
near certainty, had previously to bear up under the uncertainty of the
one-synapse-one-bit guess.  That guess has now been confirmed, which
supports the quality of the guess(es), the quality of the analysis, and the
strength of the conclusion.

I have not presented here any details of the analysis which leads me to my
optimistic conclusion,  it would take more time than I am willing to give
at the moment, so no one need feel inclined to share that conclusion. But I
will submit this one little comment which ever and again bears repeating
and is central to that analysis.  Always strive to distinguish between
STRUCTURAL damage and INFORMATION damage.  As an example:  take an ornate
glass sculpture, put it in a leather bag, flail the bag until the sculpture
has been reduces to a million tiny glass shards, pour the shards into a
bucket.  The sculture has been almost obliterated structurally. Yet the
conformal surfaces of  the shards retain with almost perfect integrity the
information about the original structure.

The human body, to be sure, is not a glass sculpture, yet every synaptic
transmitter on a (neuron to neuron)axon, has one and only one synaptic
receptor on a dendrite, and every torn membrane, organelle, or microtubule
has a unique, conformal, complementary other half; and the totality of
these pieces constitutes a profoundly dense information "space" which maps
back to the original structure from which we may seek to retrieve the vital
crucial information.  (Even if, like pieces of a jigsaw puzzle in a box,
they have been separated and jumbled.)  I frankly admit that I don't have
the expertise in information theory to predict the final outcome of this
question one way or the other.  But while waiting for some scientist
somewhere to announce that breakthrough, I'll make my guess based on the
richness of the information "space" created by the cellular matrix.  I see
success as a near certainty.

Structure is not information. Structure is visually accessible, tangible,
and familiar; information is arcane, abstract, unfamiliar, and
inaccessible.  As such, as humans, we are naturally predisposed to have our
attention drawn to, and our sense of what is relevant assigned to the
former, and to misperceive or fail to perceive the latter.  Yet if repair
technologies ever become available, then structural integrity becomes
irrelevant and information integrity becomes everything.


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Also from the paper cited: 
 
>Therefore, modifications of the amount of
>neurotransmitter that is released during LTD can be neglected. 

Though the data is flimsy and the potential pitfalls many, let's see what
can be made of the above comment.

First, for clarification.  The author uses the term "during LTD".  I
believe what he means is "while the receptor site is in the LTD state".
That being the case, the author seems to be saying that regardless of the
amount of neurotransmitter being squirted(expressed) at the receptor site,
the receptor does not trigger(respond).

Recently Mike Darwin suggested that the nature of identity/thought
/memory/consciousness might be evanescent, he compared it to the fleeting,
fluid quality of the film on a soap bubble (the swirling patterns seen on
that film?).  

Now, if the LTD/LTP (off/on) binary state of the synapse has been found to
be so robust that the researchers who wrote this paper suggest that, flush
it with neurotransmitter how you will, off is off and this synapse will not
trigger, then I leave it to you to "guess" just how fleeting may be the
substrate of personality.


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Finally, some comments.  If a brain cell has a thousand synapses, is that
five hundred dendritic receptors and five hundred axonal transmitters?  If
a receptor may be in the off state, what good is it, unless it may be
reconfigured back to the on state, and then off, and then on,...etc.?  If
the inventory of receptors is some off and some on, and there are, say,
five hundred receptors what is the total number of possible input
configurations of that neuron?  (2^500 (=3.27 x 10^150) ? Whoa, baby!)
Plus, let us not forget that the total number of neurons in ye olde brain
panne is a (by comparison) paltry, some n x10^9.  Is there some weighting
mechanism in the interior of the neuron, between dendritic receptors and
axonal transmitters, which further modifies or refines whatever signal that
may have been initiated by the stimulation of a given group of dendritic
receptors?  Somewhere in these unanswered questions I expect to find the
*unexpected* cleverness of nature's gadgetry.  

I mention the numbers above, because I've given some thought to what
happened to me when I went to see "Saving Private Ryan".  In the darkness
of the theater, I settled into that entranced, singularly focused mental
state.  Whereupon I was exposed to megabits of optical and audio data every
one-thirtieth of a second, for two plus hours.  Then I walked out of the
theater with substantial quantities of it in LONG TERM memory.  I don't see
how that could be possible without the kind of numbers I've bandied about
above.

As always, more questions than answers.   

			Best, Jeff Davis

	   "Everything's hard till you know how to do it."
					Ray Charles				

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