left-right reversal of CNS: Why?
kenneth paul collins
KPCollins at postoffice.worldnet.att.net
Wed Sep 11 21:02:27 EST 1996
>Further, there are a number of motor and sensory
>and motor homunculi, in thalamus and basal ganglia, and in cerebellum,
>and I'm not sure that "upside down" describes them especially well;
They're all in "perfect" register... for instance, ipsilateral primary
sensory & motor maps are "face-to-face" mirror images of each other...
the secondary sensory & motor areas "recapitulate" this mapping but have
somewhat less-well-defined topographical maps...
...so what is all of this for...?
...this particular mapping is involved in many powerful
information-processing dynamics... for instance, this particular
mirror-image mapping forms the substrate for the inverse directionality
of "fight" and "flight" responses... and at a higher-"level" of detail,
this same mapping enters profoundly into all "learning"... you see, when
one experiences anything, a sequential representation of what's
experienced occurs in sensory cortical areas... such sensory dynamics
drive "learning"... the production of microscopic trophic modifications
to the neural circuitry which encode the activation that has actually
occurred... subsequently, when an analogous motor "program" needs to be
developed, the formerly-learned sensory memory is accessed (I can
describe the "addressing" inherent in such) and used as a template to
guide the convergence of the motor dynamics... can you see it...? the
advantage that the sensori-motor "face-to-face" mirror-image mapping
implements is that the =acted-upon= sensory experience is transformed in
a straight-forward fashion to =act-upon= motor activation... there's a
bit of sadness involved here, however... these very dynamics enter
=strongly= into the dynamics of the viscious cycle of Child abuse... the
Child that is battered (acted-upon-directionality sensory templates)
becomes the act-upon motor version of those sensory templates acquired
at the hands of abusive adults... the directionality inherent in the
be-struck sensory template is inverted, automatically becoming the
directionality inherent in "striking" behavior... this all happens
because the nervous system preserves this mapping paradigm with respect
to the =whole body= ...and because of this, the CNS is able to "know"
how to activate the musculature, and to do so, via simple TD E/I
...I understand that what's here is not enough, but what's here stands
verified... ken collins
More information about the Neur-sci