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smith predictor and the cerebellum

KP-PC k.p.collins at worldnet.att.net%remove%
Wed May 7 16:10:11 EST 2003


Hi, I know nothing re. "Smith Predictors", and I don't have 'time' to
read and study the paper. but the cerebellum functions as a
generalized TD E/I-minimization mechanism. It functions to 'blindly'
and automatically minimize the topologically-distributed ratios of
excitation to inhibition that occur within the nervous system.

It does this by simply inverting all excitation that it receives,
transforming it into inhibition, so that a 'mountain' of activation
is transformed into a 'valley' of activation. This happens because
all outputs from the cerebellum arise from its Purkinje cells which
are all inhibitory.

The cerebellum does this with respect to the whole nervous system,
not just motor stuff. That this has not been generally recognized
results from the way that it's relatively easy to see the impacts of
cerebellar deficits within motor functionality, but hard to discern
the impacts to cerebellar deficits with respect to non-motor
dynamics. The impacts to cerebellar deficits within non-motor
dynamics can be discerned, however. It just requires more
information-processing work to do so.

The general thing is functional because, if a 'momentary' cerebellar
TD E/I-minimization is 'inappropriate', that will result in more
activation pouring into the nervous system from the environment. This
will force renewed TD E/I-minimization convergence - yield a 'valley'
of activation having renewed topological features.

If one spends 'time' observing Infants' relatively-'random'
behavioral dynamics - their little 'struggles' to reach for a
crib-toy, for instance, one can actually observe the long-term TD
E/I-minimization convergence that's discussed above.

All of this is tightly-integrated with a slew of other stuff,
including three other major TD E/I-minimization mechanisms.

[For those who have it, all of this stuff is discussed in more detail
in AoK ["Short Paper", Ap3, 5, 6 & 7].

Of course, due to conductancance latencies, there is 'prediction' in
the mix, but it's an 'artifact' within 'normal' cerebellar
funtionality.

K. P. Collins

--
"Schmitd! Schmitd! Ve vill build a Shapel!"
"siu99rnj" <siu99rnj at rdg.ac.uk> wrote in message
news:b9bpuk$9eu$1 at vins1.reading.ac.uk...
| hi
|
| I have just read a paper that suggest the cerebellum is two linked
smith
| preicitors.(www.physiol.ox.ac.uk/~rcm/pdf_files/SmithPred_93.PDF)
One for
| modelling motor movment. The other for modelling the delays that
occur (eg
| delay of neuron firing, axon transmission etc). The paper was
printed in the
| early 90s. I would like to know the thoughts of people here on this
theory.
| Do you think the cerebellum is a smith predictor? If not why not?
|
| A good explanation of the smith predictor is
|
http://www.manufacturing.net/ctl/index.asp?layout=articleWebzine&arti
cleid=C
| A188333
|
| If people could let me know their thoughts I would be most
grateful.
|
| Thanks
| Richard
|
|





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