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Article 2375 of comp.ai.philosophy:
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>From: geb@speedy.cs.pitt.edu (Gordon Banks)
Newsgroups: comp.ai.philosophy
Subject: Re: Scaled up slug brains
Message-ID: <12819@pitt.UUCP>
Date: 23 Dec 91 15:28:59 GMT
References: <45210@mimsy.umd.edu> <12804@pitt.UUCP> <45350@mimsy.umd.edu>
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Reply-To: geb@cs.pitt.edu (Gordon Banks)
Organization: Computer Science Dept., University of Pittsburgh
Lines: 128

In article <45350@mimsy.umd.edu> harwood@umiacs.umd.edu (David Harwood) writes:
>In article <12804@pitt.UUCP> geb@cs.pitt.edu (Gordon Banks) writes:

>I asked. (I think brain specialization in humans is marked; as I have
>observed we have several unusual features: expressive faces, vocal cords
>and complex speech production and recognition, color vision, great

The facial expressions are largely interpreted by the right hemisphere.
The great apes have very expressive faces and our neural machinery
is quite capable of decoding their expressions of joy, anger, etc,
as they are similar to ours.  Patients with right hemisphere stroke
can have difficulty reading emotional expressions on faces.

>	But what bothers me about replying to you is that you do not
>quite reply to what I asked? You referred to the work of a colleague,
>and I asked (not as a criticism) what was the connection between 
>territoriality and spatial perception vis a vis lateralization. You did
>not answer. Would you simply give me a reference to a publication, and
>I will be happy to read for myself?

The connection is that voles that are lateralized have large 
sexual territories (in the males) and voles that are not lateralized
stick closer to home.  I thought I had said that before, but if
not, I'm sorry.  I don't have his cv with me, but if you email
me again after Jan 1, I'll call him and ask him for the best
article to read on the subject.  (I'm going out of town until
then).

>	(I previously referred to effects of sex hormones on brain
>development; I recall that there is some controversial evidence in humans
>that certain human spatial abilities are sex-linked.)
>	What is the role of sex-hormones in neonatal development of the
>two animals - one territorial and spatially lateralized, the other not?
>
The males of the lateralized voles are the ones that are strongly
lateralized.  I don't know that the role of hormones in producing
the lateralization in the voles has been studied or not.  There have
been some articles on this, but this is a controversial subject, since
a lot of feminists object to such research findings.


>	So you agree that mammals are not "scaled-up" slug brains,
>anymore than they are not "scaled-up" bird brains? I think there is
>some hope here.

If you read what I posted, I objected to the use of the words "scaled-up",
which were never mine.  They were attributed to me by my opponents in
the argument.  I do, however, hold that our brains are "evolved-up"
from simpler brains, although whether any slug is in our family tree
is doubtful.

>	I would be interested to read any of your publications in
>your field of human neurology, which you feel might be relevant to
>our discussion. (Mine are in computer science in the fields I mentioned,

My publications are mostly dealing with clinical syndromes and not
basic research in neuropsychology.  For that, I recomment Ken Heilmann's
Clinical Neuropsychology, Andy Kertesz's Localization in Neuropsychology,
or Mesulam's Principles of Behavioral Neurology.  Most of this (the human
side, not the animal side) is discussed extensively in these books.
Springer & Deutsch's Left Brain Right Brain is also an excellent
place to read about lateralization.

>	Yes - but don't these patients, unless they are very young,
>have difficulties? And even if they are older, don't they often fail
>to recover their full language abilities? 

Most have some trouble, but some recover to the point you wouldn't
know the difference.

>And don't many people who
>fail to show "normal" lateralization in various respects also often
>show various linguistic disabilities? 

No.  Turner's syndrome patients have no detectible lateralization
and they are above average in linguistic abilities.  It is their
spatial abilities that are dismally poor.

>And aren't isn't there some
>lesser verbal processing by the right brain even in "normal" people?

The right hemisphere normally will interpret the emotional content
of speech (tone of voice, etc.).  As I said the ability of the right
hemisphere to carry on with semantic and syntactic processing varies
between individuals.  Some after L hemisphere damage are almost
normal, others are permanently and totally aphasic.

>And don't people with major parts of right hemispheres damaged or
>surgically removed still have relatively normal verbal abilities and
>reasoning, while the opposite is disastrous, even detroying apparent
>self-conscisoness?

This is a serious misconception that many people (even doctors who
are not neurologists) have.  Right hemisphere strokes can be
devastating despite the preserved verbal ability.  They can leave
the patient an emotional cripple, unable to express their own
emotions or understand those being expressed by others.  They
can cause the patient to be unable to orient themselves spatially
and geometrically, unable to dress, navigate around the house, etc.
They are much worse than people think.  Patients with aphasia after
L hemisphere stroke, despite wipeout of language, often do better
than right hemisphere strokes.  My patients who are aphasic appear
to me to be perfectly conscious, they express emotions, frustration,
and the gamut of human behavior except for language.  Since one
can not effectively communicate with them, it is hard to understand
what is in their consciousness, but I have no reason to believe they
are incapable of reason or self-consciousness. They recognize their
relatives, show and accept love, etc.  They may be incapable of the
degree of introspection necessary for what some philosophers consider
consciousness, but I'm not sure their definitions are that relevant here.

>linguistically disabled. In fact, such (genetic) variations could be 
>advantageous in some respects. For example, possibly Einstein may have 
>been somewhat dislexic, and verbally retarded as a very young boy, and
>while his mathematical skills perhaps were not outstanding (see his
>correspondence with mathematicians; he even had assistants to help him
>mathematically), his spatial/geometrical and physical/kinesthetic

His arithmetical skills, you mean.  His mathematical skills were
unexcelled.



--
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Gordon Banks  N3JXP        | "When in danger, or in doubt
geb@cadre.dsl.pitt.edu     |  Run in circles, scream and shout" --Heinlein
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