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From: smoliar@vaxa.isi.edu (Stephen Smoliar)
Newsgroups: comp.ai
Subject: Re: Building a brain, revisited
Message-ID: <11324@venera.isi.edu>
Date: 10 Jan 90 15:14:52 GMT
References: <15439@well.UUCP> <11673@csli.Stanford.EDU>
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Reply-To: smoliar@vaxa.isi.edu.UUCP (Stephen Smoliar)
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In article <11673@csli.Stanford.EDU> ceb@csli.Stanford.EDU (Charles Buckley)
writes:
>
>Brains do things that hypercubes don't though, which is learn, and
>that learning is reflected in the topology.

While I find myself about as reluctant to use the word "learn" as the word
"understand" these days, I think it is important to grant the observation
about topological modification.  However, brains have an even more subtle
property than hypercubes which has received occasional reference in the Searle
debate.  Cells have finite endurance and are regularly replaced in the
organism.  Perhaps more remarkable than the fact that a topology forms
and is modified is the fact that it is MAINTAINED--that new nerve cells
can come in and fill in for old ones without disrupting that topology.
It would seem that we are a far cry from a piece of hardware which, as
part of its operation, keeps itself furnished with fresh components;
and we probably do not want to write off the possibility that such maintenance
operations may be strongly connected to the behavior of the agent.
>
>Topology changes as a product of learning?  Seems quite open to me,
>but I'd like to hear of efforts in this area.


A good place to start might be Gerald Edelman's NEURAL DARWINISM.  In
particular, Chapter 5 is entitled "Cellular Dynamics of Neural Maps."
He presents several examples in which topological reorganization has
been observed in adult brains.  Experiments by Merzenich's group were
able to induce such reorganizations by cutting a specific nerve.

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