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Article 2131 of comp.ai.philosophy:
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>From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: comp.ai.philosophy
Subject: Re: From neurons to computation: how?
Message-ID: <318@tdatirv.UUCP>
Date: 14 Dec 91 18:48:12 GMT
References: <40332@dime.cs.umass.edu> <12616@pitt.UUCP> <40375@dime.cs.umass.edu> <12636@pitt.UUCP> <59809@netnews.upenn.edu> <310@tdatirv.UUCP> <60059@netnews.upenn.edu>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
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In article <60059@netnews.upenn.edu> weemba@libra.wistar.upenn.edu (Matthew P Wiener) writes:
|"Mind" is one of those things that neurobiologists get real edgy about.
|A few have offered models (Eccles, Sperry, Edelman), but most settle for
|the understanding of low level processing, like vision.

And right now, I am assuming that the same basic principles operate in the
more cognitive parts of the brain as operate in the simple, sensory processors.

|>Fine, and when someone does this experiment, *and* it shows a
|>*psychologically* relevant effect as far as the human mind is
|>concerned, I will keep to the simpler theory.
|
|And how does computation show any special *psychologically* relevant
|effect?

I am talking about models of brain function and cognition.  A model of some
component of the brain is only relevant to the formation of cognitive
activity if it *contributes* to cognitive activity.  In practice, with humans
at least, this is 'psychology' in its most general sense.

Until there is a set of experimental results linking a specific low level
effect with *behavioral* or *cognitive* results, it may represent cognitively
irrelevent detail.
|
|Indeed, the whole idea of saddling neurobiology/psychology with the AI
|theme song is totally anti-Occam.  

Actually, I thought I was going the other way.

I was viewing neurons from a biological perspective.

|>So, enlighten me.  What relevance do these have to human psychology?
|
|As much, more, or less than computers.

In what way does this sort of thing effect cognitive processes.
That neurons are input-output data transformers is know, and it is
clear how *this* could effect cognition.  There is no evidence I know
of for the relevance of this Bose-Einstein condensation effect.

|>And I mean computable in the sense that physical computers as we build them
|>today could compute the same data transform as any given neuron (including
|>the temporal variability we calling learning).
|
|>I conclude it because all that I know about the operation of neurons (and
|>that is considerable, since I am by background a biologist) is fully
|>consistent with the theory that it is only the signalling properties
|>of a neuron that are relevant to thought.
|
|Really?  Then what is all that brain EEG going on for?  It is not noise.
|EEG activity can be correlated with thought.  Correlating it with neurons
|is not easy.

As I understand it, an EEG is essentially just a regional summation of
neuronal activity.  Thus, whatever an EEG is doing, it is because some
population of neurons is doing something specific.  That is, the EEG is
the large scale result of the information processing activities of a
family of interconnected neurons.

It is true that at this time the exact details of the correlation have not
been worked out, but recent studies have shown that, at least in the olfactory
cortex, the EEG patterns generated are tracable to neural-net type interactions
amoung the individual neurons.  [there is now a NN model that correctly
mimics the operation of the olfactory cortex, and generates equivalent
activation patterns].
|
|>is even reason to doubt that the *individual* synaptic junction is of
|>much significance, but that it is rather *clusters* of synapses, and clusters
|>of firings that constitute the operational unit of the neuron, if so then
|>variations in the response of a single synapse will not change anything unless
|>it is correlated with matching differences in associated synapses.
|
|Right.  This is the start, for example, of Edelman's Neuronal Group
|Selection Hypothesis, which I haven't had the time or knowledge to
|rant about yet, but I hope I've implied that I look favorably upon.

If this is what I think it is, so do I.  But it still seems to me to be
*computable*, so it does not invalidate the strong AI hypothesis.
[Especially since the relevant feature of the synaptic cluster seems to be
that it is one way of representing connection weights, so a computer version
could, concievably replace the synaptic group with a parameterized connection].

|>In order to challenge this conclusion you must show behaviorally or
|>informationally relevant effects that are not derived from this type
|>of operation.  As far as I know, no such effect has ever been found.
|
|There are numerous such effects known, although they are usually not
|described in this sense.  For example, human beings need sleep.  And
|when awake, they need stimulus or else they go nuts.  These are baf-
|fling and/or bewildering from a purely computational point of view.

O.K, now how does the Bose-Einstein effect explain this?
If it doesn't, then it has no better claim then the simple data transform
model.

|Your "in order to challenge" is incomplete, by the way.  I can also
|challenge the computational mind paradigm from the other side: forty
|years of coming up short is a dismal record for any research claim.

It now seems to be making progress though.  And it the effect your are talking
about adds another layer of relevant entities to the model of the mind, so
it requires extra evidence.
-- 
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uunet!tdatirv!sarima				(Stanley Friesen)


