Date: Fri, 03 Sep 1999 11:46:37 +0200
From: "Gatherer, D. (Derek)" <D.Gatherer@organon.nhe.akzonobel.nl>
Subject: RE: Differentiation/Merging of the senses
To: "'memetics@mmu.ac.uk'" <memetics@mmu.ac.uk>
Chris:
Which aspect do you reject -
(a) that we start-off with undifferentiated sensory processing that then
becomes refined through exposure to nurture?
(b) that we end-up creating hybrid expressions of meaning based on the
entanglement of sensory data?
(c) all of the above
Derek:
all of the above, it's just conjecture.
Chris:
does the 'fact' that sensory specific areas of the brain, if not exposed to
their particular sense bias (e.g. due to blindness, deafness etc) are
recruited by surrounding networks for different tasks? Doesnt this
demonstrate the undifferentiated form of the brain in early development?
Derek:
No, it demonstratres a degree of neuronal plasticity, that's all.
Chris:
One
example of this was the forceable closure of an eye during the first few
weeks of life (in monkey). Later examination of the visual cortex showed
that the network used by the other eye enchroached on and 'stole' parts of
the network for the closed eye.
Derek:
Yes, Colin Blakemore's classic experiment. So what? The monkeys don't end
up hearing sights or seeing sounds.
Chris:
These observations manifest a plasticity 'in here' that would include
'entanglements' where lack of exposure to sensory data reduces
particularisation and the areas concerned are returned to a general state
that lets them be recruited by near-by specialist regions.
In this context, the newborn infant has a brain that is 'general' in form
when compared to later particularisations due to nurture. The
object/relationship distinctions, the what/where mappings, are there but not
yet refined such that the border between them is not sharply defined, there
are entanglements where a neuron or network of neurons are in a 'general'
state and this general state is manifest as synaesthesia.
Derek:
Well, no because then everybody would be synaesthetic as part of their
normal development, and it's quite clear that synaesthesia is a rare
condition indeed.
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