>Subject: Re: brain plasticity - what causes it?
>From: jander at unf.edu (John E Anderson)
>Date: Sat, 06 November 1999 09:37 AM EST
>Message-id: <38243B60.F9787ABC at unf.edu>
>>> it's my view that the nervous system, =as a whole=, remains 'plastic'
>> throughout life,
>>That has to be the case, at least in higher cortical areas (and maybe
>throughout the NS), otherwise we couldn't learn anything. But I have a
>very specific question. When neurons are active (fire action
>potentials) they release neurotransmitters and neuromodulators of
>various sorts. Some of these things must be responsible for inducing
>plasticity -- rearrangements in the surrounding brain tissue. My
>question is do *all* neurons produce whatever it is that induces
>plasticity, or only some?
all of the stuff to which you refer reduces to TD E/I... it's TD
E/I-minimization; the convergence inherent in it, which augments particular,
minimal activationstates as convergence upon TD E/I(min) occurs, that is the
thing that determines 'plasticity' ('memory', which is extremely-very-much-more
than 'just' verbal-symbolic stuff; it includes =all= neural-activation
correlates, including endocrine stuff), there are many neurochemical
involvements; as is discussed in AoK, Ap9 ("functional multiplesing'), none of
these is 'carved in stone' with exclusive respect to this or that 'plasticity'.
this's why it's necessary to reduce everything to TD E/I with respect to the
rigorous mapping of the external and internal Geometry... "TD E/I-minimization
is 'just' =Geometry=.
a correlated thing is the way this or that 'drug' always produces unwanted
side-effects. all 'drugs' efficacies are dependent upon 'momentary' supersystem
configurations (AoK, Ap5), and if 'drugs are 'just' administerd, their effects
'cut-across' normally-multiplexed neural topologies, =without= benefit of the
'chemical insulation' (AoK, Ap9) that's 'normally'-occurring... the
'side-effects' occur as a function of this 'functional-multiplexing'
for 'drugs' to be used as Truly-specific 'treatments', the particular
supersystem configuration, with its correlated 'functional multiplexed'
'state', would have to be induced simultaneous with the application of the
'drug'... an analogy from chemistry is that current use of 'drugs' is like
creating a 'mixture', when what's needed is to create a specific 'compound'.
the former has no discrete Geometry (Topology), while the latter does.
it's a difficult problem because disease conditions typically destroy, to a
degree, the ability of the nervous system to converge upon specific supersystem
configurations. effective use of 'drugs' would have to restore such. but how
can such be achieved when the underlying tissue has 'gone away'?
anyway, 'plasticity' occurs as a function of TD E/I. everything has to be
'translated' into abstract TD E/I before any correlation to the actual problem,
that of the internal-external Geometry synchronization, can be, in any way,
different chemical substances are involved at different sites, and have
different functionalities at different sites, depending upon the 'momentary'
one cannot say 'this or that' about a specific neurochemical's involvement
without specifying the supersystem configuration.
but one can say everything about such by 'just' teanslating into TD E/I, and
describing TD E/I, and its minimization, as they are correlated to pre- and
in the future, it may be the case that the tissue deficits that constitute the
substrate of disease symptomology will be overcome. =then= it will be practical
to address neurochemical specificity, as above, because it will, then, be
possible to simultaneously discuss particular supersystem configurations and
specifically-functionally-multiplexed 'states'... and to create 'compounds'
rather than 'mixtures'.
until then, there's a vast literature that addresses the stuff of your Q from
the inadequate perspective of 'mixtures'. if you want to know what it says,
(forgive me. i've a 'thing' against rehashing what's already in the literature,
and, as i did in AoK, try to discuss only what's not already in the literature,
because what's already in the literature is already in the library, ready and
waiting for anyone who wishes to access it. try to understand my position. i
don't want to be a 'servant' of what, although wonderful in it's own right,
still remains inadequate, "just to 'fit-in'".)
cheers, John, ken (K. P. Collins)