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Neuron-glia interaction

kenneth Collins kpaulc at earthlink.net
Tue Jan 11 16:59:37 EST 2000


there is an electron-microscopy Tour de Force article in _Natur
Neuroscience_, v2 n2, Feb., 1999, p139, "Microdomains for neuron-glia
interaction: parallel fiber signalling to Bergmann glial cells", by J.
Grosche, et. al.

although it deals with cerebellar fx, the stuff of this article Confirms
NDT's glia hypothesis, as it's briefly discussed in AoK, and which dates
from the mid 1970s.

HURRAH+++***!!!

beyond this Confirmation, the flat-out-obvious activation-dependence
that's disclosed in the stuff of this article is also cause for
celebration.

NDT's hypothesis is that the 'elements' to which the article refers to
as 'microdomains' are structurally-configured in an activity-dependent
way.

such is easily seen in (quoting from the article):

"In cerebellar development, the Bergmann glial cell fibers are important
in guiding immature granule cells away from the external granular layer.
During granule cell migration, the glial cells processes are rather thin
and smooth, except for occasional bulges due to mitochondria. This
appearance changes dramatically as soon as the granule cells have
reached their target zone. Then, the stem fibers thicken and develop a
massive outgrowth of lateral branches."

discussion: one can =see= the activation-dependence in all of this,
begining right in the DNA, deriving in the energy-flow assymmetry
resulting from the first mitosis, and extending throughout Life in
unbroken everywhere-continuous actavation-dependence.

early cell proliferation is just following the energy-flow asymmetry
that results from early mitosis. cell-differentiation begins when each
cell's DNA-activation, by then-current energy-flow asymmetry in each
cell's vicinity, 'makes it easier' for intracelular dynamics to occur
than further mitosis.

this 'interplay' between mitosis and intracellular development (cellular
differentiation) goes back and forth, =always= inaccord with 'momentary'
energy-flow dynamics.

in the sentences quoted above, we enter the development of Bergmann glia
and their correlated neuronal 'buddy' cells at a relatively-advanced
stage of development.

in this stage of development, the 'guidance' is =mutual= between glial
and neuronal cell types. each is 'just' doing the minimal-energy-flow
thing that results in their collective appositions. the granule cells go
with the energy-flow inherent.

when one looks, one =sees= that the Bergmann cells' transition from thin
to massive varigation is triggered by the energy-flow dynamics that
result from granule cells' newly-occuring interactions with other stuff
in their target zones.

in their discussions of manipulations of ionic conductances in
relatively-mature cells, the Authors have, in fact, nicely delineated
some of these energy-flow dynamics in their paper, although
'unknowingly'.

in 'mature' cells, ionic conductances are one-and-the-same with the
energy-flow dynamics that have been discussed above, and cellular
asymmetries, which embody information-processing capacities, develop as
a result of stuff 'just' going with the flow of energy.

the Authors' paper is one of the most-Beautiful Neuroscience papers i've
ever studied. i 'found' only one common 'oversight' in it; a bit of
short-sightedness in interpreting in vitro dynamics with respect to the
in vivo reality.

the 'compartmentalization' of the 'microdomains' that the Authors point
to is not as delineated as the Authors claim, because the functioning of
each such microdomain is, necessarily, coupled to the =overall=
activation dynamics, not just their local ionic conductances.

that is, the microdomain functionality is somewhat analogous to
'letters-of-an-alphabet' stuff, while overall functionality is like
'words-sentences-paragraphs-books' stuff, with each microdomain
contributing its 'letters-of-an-alphabet' stuff within the overall
'words-sentences-paragraphs-books' stuff, which means that there is,
necessarily, a global integration that 'couples' the
relatively-'discrete' microdomain functionality.

the easiest way to see such is to just 'travel' with feed-forward and
feed-backward activation dynamics... it's all 'just' energy-flowing
toward TD E/I-minimization.

and, since trophic dynamics are also rigorously-coupled to the
energy-flow dynamics, as was discussed above, all the way down to the
DNA, the trophic dynamics automatically imbue the activation dynamics
with 'memory' with respect to any energy-flow dynamics that is, in fact,
experienced.

subsequent recurrence of 'similar' energy-flow dynamics automatically
invokes it's correlated former-energy-flow-driven trophic results, which
are the 'biological mass' that's briefly discussed in AoK, Ap5, which
exerts its 'behaviroal inertia' back upon the energy-flow dynamics,
which is the form of our extraordinarily-capacious activation-dependent
'memory'.

so the 'microdomains' are actually in communication with one another.

it's activation-dependence all the way down.

what imbues all of this with functionality is it's globally-rigorous
coupling with the 'special topological homeomorphism' of the nervous
system (see AoK), which is, in turn, rigorously-coupled with the
Universal energy-flow that is the one-way flow of energy from order to
disorder that is what's described by 2nd Thermo (wdb2t).

deviations from wdb2t are detected in the form of TD E/I(up) within the
nervous system, with ensuing supersystem configuration (AoK, Ap5) that,
itself, is activation-dependent, via the 'special topological
homeomorphism', with respect to Universal wdb2t.

what a Beautiful, strongly-confirming-of-many-things paper J. Grosche,
et. al. have produced!

cheers, ken (K. P. Collins)

[P. S. the stuff of every Neuroscience paper that's ever been published
can be discussed from the perspective of the stuff that's discussed in
this msg, and when such is done, the Science is =always= Advanced,
which, itself, stems from the fact of wdb2t. KPC]




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