johnh at faraway.hgmp.mrc.ac.uk
Thu Mar 11 05:00:44 EST 2004
"Peter F." <effectivespamblock at ozemail.com.au> wrote in message
news:kXl3c.183$KJ.8628 at nnrp1.ozemail.com.au...
> "John H." <johnh at faraway.> wrote in message
> news:404d8995 at dnews.tpgi.com.au...
> > 07/03/04 11:27AM
> > JH:
> > I wonder if Chomsky's ideas gave rise to the modularity concept. Both
> > deeply flawed, if the work of the British neurosurgeon John Lorber
> > put it to rest then surely the recent work of Ed Traub (Contraint
> > movement therapy) has nailed modularity deep into hell.
> I don't believe (or at least hope) you don't sincerely and deeply wonder
> that Chomsky's ideas did so.
> Much more meaty discoveries (than Chomsky's hypothesis) motivate the
> thinking in terms of mental (brain fucntional) modularity;
You are correct there, probably can go at least all the way back to Wernicke
and Broca. Then was added regions of the dlpfcs to higher language
functions, regions of the temporal lobes are implicated, and then the
cerebellum (of all places) also plays a role. What next?
> E.g., the much publicized research by Hubel and Wiesel on kittens drew
> people's attention to not just a certain experiential neccessity behind
> visual perception but also a certain microanatomical aspect of _neatness_
> about how retinal information ends up being processed partly by neurons in
> 'striped' (columnar) configuration in the primary visual cortex.
> A very similar inspiration to thinking in terms of modules might be gotten
> from corpus striatum of the basal ganglia.
> And there are of course many other reasons for ideas of the brain as a
> collection of modules -- not the least an as basic and simple a reason as
> the general 'structional' properties of nerve-cells themselves.
Okay, there is a certain style of modularity in the brain but if you examine
the data you also find some very intriguing exceptions. Last year some
German scientists studied how female brains handle language through the
course of the menstrual cycle. To their surprise they found noted
differences across the cycle. Not small regionally specific differences
either, but wholesale changes in left-right balance in language production
and comprehension. Caveat: can't remember if it was fMRI or PET study, fMRI
may not be as reliable as we would wish, I have noted references (but lost
in my archives at present) indicating that fMRI images can altered by a wide
range of factors. The picture doesn't always tell the story.
A few years ago it was suggested that the reason why some women have
conceptual difficulties in menopause is because their brains are undergoing
subtle changing in functionality. Given that androgens play relatively minor
roles in the cerebral chemical symphony these two results are rather
surprising. I suspect that as we all age the brain is continually adjusting
its structure to reflect the changing state of the brain.
Constraint induced movement therapy, which produces seemingly miraculous
results if one adopts a strict modularity hypothesis, certainly does raise
some fundamental questions about brain organisation and plasticity.
The work of John Lorber on microencephalics and\or those who had shunts
inserted because of hydroencephalus raises some perplexing questions about
brain organisation. Some of these shunts failed and the individuals
experienced substantial loss of cortical tissue, yet one of them was a
honours student in mathematics and no identifiable pathologies though subtle
testing will reveal differences but in practical terms these differences are
often insignficant in practial terms. Compensation. What would be
interesting in such cases is
what happens as they age. There are also numerous clinical cases of
individuals who have experienced considerable brain damage and been advised
that they would always suffer this or that deficit yet the recovery has been
very pronounced and left the doctors completely puzzled.
Qualification: I did a search for his work and it turns out there has been
precious little follow up. John Lorber documented over 600 cases of
individuals with severely reduced cortical thickness (CAT scan). One in
particular had only 1 mm, avge is 45mm, with IQ126 and a first class honors
student in mathematics. Unfortunately, as so often happens with such
findings, the scientific community conveniently ignores the same. I've
downloaded one journal article on this issue and will read it later. By the
way, John Lorber was a Professor of Neurology at the Uni of Sheffield so in
the first instance I'm inclined to examine what he says, whereas many rely
on that bloody insidious redundancy argument, yet another example of ad hoc
explanations in Neuroscience.
The point is this Peter: As the physicist John Wheeler once commented, "In
any discipline find the strangest thing and then explore it." In
Neuroscience it seems that many fail to appreciate the wisdom of this
advice. I'm a rampant iconoclast, and being blessed with a good memory, well
I'm just a real bastard to deal with at times.
Some may say that reward processes are mediated by the VTA - Acc - PFC
dynamics, I suggest this simply reflects our current state of knowledge. No,
I'm not opting for a Lashley style of distributed processing, I think
Lashley's results are better explained by reference to the immunological
impact arising from multiple cortical insults.
Shallice &??? put forward a supervisory attention system, Goldman-Rakic and
others argue for multiple attentional processes. A typical example of the
history of neuroscience. It starts out simple then just gets messier and
messier ... .
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