memory (and SOMs)

mat mats_trash at hotmail.com
Tue Feb 26 08:00:15 EST 2002


> 
> According to one study, there are about 32 visual areas in the macaque
> visual cortex, connected by 305 connections. Now it seems that these
> visual maps cannot be the result of self-organization, so they must be
> genetically specified. If this can happen to the visual cortex, the rest of
> the cortex might be organized this way too. By simple division we can
> estimate that there could be 100 to several hundreds of  "maps" in the
> cortex. That is the number of circuits we have to figure out!

I think you should be weary in any part of biology of using the term
'genetically specified'.  What do you actually mean by this?  Sure the
growth factor peptides are of course genetically specified, but to
suggest that the genome has much control over what happens to the
peptide is very debatable.  DNA encodes proteins and is regulated by
proteins and as such is not much more than a 'library' accessed at
intervals.  Further, the actions of proteins themselves is
inextricably linked to the macro and microenvironments of the
organism.  Though DNA contains the code, in my view environment plays
at least as much if not greater role in shaping the organism,
including its brain.  Therefore there will always be some element of
self-organisation, though not perhaps not in the strict Kohonen map
sense.




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