> From: "Harrison, Richard" <RJH93PY@psy.soton.ac.uk>
> Date: Fri, 10 Nov 1995 12:46:21 GMT rh>
rh> IS [anosognosia] connected with frontal cortex damage?
It's connected with limbic system damage, and the frontal cortex is part
(but not all) of the limbic system.
rh> Some of Z's writing indicate he had a much greater awareness of his
rh> past when he was writing than he had at the time he actually
rh> had the experiences. This seems to suggest a quite impressive
rh> improvement over time but could just be a consequence of his
rh> 'discovery' of automatic writing.
Hard to say whether what he got through performing the act of writing,
which he could already do, counts as further functional recovery. Life
goes on after brain damage, and if memory and intellect are intact,
there is new knowledge, but recovery of lost function is something
else, and does tend to happen mostly in the first post-injury year (or
even shorter), especially in adults.
> sh> With Z you are really sampling the A-Z of neuropsychological disorder.
rh> All without anosognosia...
Well, the ones he TELLS us about he knows about...
rh> In some respects [S and Z] do appear to be opposites but they do both
rh> appear to lack the ability to form abstractions. A similarity
rh> between two people who couldn't seem more unalike?
Right, and many people have singled this out as a general correlate of
all kinds of brain damage: I think it was Hughlings Jackson (no, someone
else) who called it deficit in the "abstract attitude."
But S's abstraction problem seems more one of FORMING abstractions, Z's
with naming them or perhaps expressing them.
> sh> This explanation (of Luria's) is obviously too vague and general; to the
> sh> extent it means anything at all, it is really just a restatement of the
> sh> symptoms:
rh> What WOULD count as an explanation?
Good question. It is not enough to talk about deconnections: the THIS
center is disconnected from the THAT centre; nor about vague verbal
descriptions of "functions" performed here there or everywhere in the
brain. We need a model that can do what the brain can do, and then ITS
breakdown with damage can give us an idea of the effect of damage on the
brain. And I don't mean a toy model that does a tiny bit of what the
brain can do, and the rest is all just disconnection, or what have you:
The brain's POSITIVE capacity has to be explained before we can explain
negative things, like breakdowns and deconnections.
rh> I don't know. Are there satisfactory explanations for any
rh> neuropsychological phenomena and if so what are they like? Or are we
rh> running into the Mind-Body and Other Minds problems again?
Few satisfactory explanations yet, for lack of the positive theory, I
think. And yes, there is some of the old mind/body and other-minds
problem lurking in neuropsychology, in that we tend to think pretty
homuncularly about "functions" -- not just in the split brain, where we
explicitly talk about two minds in the same head, but when we talk
about centres and modules too: Or perhaps they're doomed to be just
little men in the head till we cash them out into models that actually
deliver the goods without a homunculus.
Trouble is that the only goods the models can deliver are behavioural
(and physiological) goods: You can never know if they deliver the mental
goods, and that IS the other-minds problem.
> > rh> Analysis of a short comprehension test shows Z could only understand
> > rh> one word at a time and not combine them to form the intended image
> > rh> main point.
rh> Maybe due to a different cause (OK this is extremely likely), but at
rh> a functional level (e.g. output of a comprehension test) S has problems
rh> understanding the intended meaning of prose as well.
Not quite sure what you mean here.
> > Myrna Gopnik
> > http://cogsci.soton.ac.uk/~harnad/csctalks.html#gopnik
> sh> spoke here at the Cognitive Sciences Centre about what seems to be a
> sh> hereditary brain disorder that specifically causes this kind of
> sh> grammatical disorder only.
rh> From Gopnik's abstract:
> >Cumulative data from several years of testing across several
> >languages show that a genetic disorder can affect the ability to
> >build a normal, rule-governed grammar and that in the absence of this
> >ability subjects resort to other cognitive strategies in order to
> >construct a language-like system.
rh> Is there an explanation beyond the observation that it's 'genetic'?
rh> And if not, even if the gene/gene combination were discovered we
rh> would have a cause but would this be an explanation?
Yes, they there are a few theories: One is that the gene codes for
sensitivity to word endings and word order; another that it may even
code for a fragment of Chomskyan Universal Grammar (as designed in MIT).
But you're right, a genetic analysis is not a cognitive analysis, which
would have to explain, first, our positive syntactic capacity, and then
the negative data, when it's disturbed or lost.
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