[From Bill Powers (961023.1030 MDT)]
Bill Benzon --
I think those efferents in the
optic nerve must be doing something to the retinal perceptual systems.
What, I can't imagine.
But it probably has something to do with controlling perception. 'Cause
what else is there to control?
Something, sure. But I haven't any idea what. I've never seen any data about
the effects of signals in these pathways. In fact, aside from one mention in
a neuroanatomy text, I've never seen any discussion of them at all.
With regard to your ideas about "memory boxes," I think you'd better
elaborate on just what it is that a memory box does. If all it does is
record and play back signals, it seems to me that there a lot of missing
mechanism, like the signal generators and the functions that relate one
signal to others. A model made entirely of memory boxes wouldn't seem to do
much.
...if you think of the cortex as
consisting of some 100 to 1000 memory boxes, each with input and output
connections to various cortical and subcortical regions, then you're going
to get some very sophisticated and complex dynamics as the system juggles a
50 or 100 (not all cortical regions will be functioning at once)
simultaneous reference patterns, continually "swapping" patterns in and out
of the stack to account for current sensory input and direct motor output.
That's a pretty vaporous model. What kind of "juggling" are you talking
about? What actually does the "juggling?" And what does the "swapping?"
These are surely not memory functions. And to say that "patterns" are
swapped in and out of "the stack" to "account" for current sensory input and
direct motor output is just plain arm-waving. You haven't spelled out a
single function of this model! Given 100 or 1000 memory boxes that swap and
juggle and account, I doubt that anyone could say what such a system is for.
What you've described so far doesn't sound like modeling to me.
Best,
Bill P.
Bill Powers (961023.1030 MDT) sez:
With regard to your ideas about "memory boxes," I think you'd better
elaborate on just what it is that a memory box does. If all it does is
record and play back signals, it seems to me that there a lot of missing
mechanism, like the signal generators and the functions that relate one
signal to others.
Just what doe your memory boxes do beyond record and playback signals?
...if you think of the cortex as
consisting of some 100 to 1000 memory boxes, each with input and output
connections to various cortical and subcortical regions, then you're going
to get some very sophisticated and complex dynamics as the system juggles a
50 or 100 (not all cortical regions will be functioning at once)
simultaneous reference patterns, continually "swapping" patterns in and out
of the stack to account for current sensory input and direct motor output.
That's a pretty vaporous model. What kind of "juggling" are you talking
about? What actually does the "juggling?" And what does the "swapping?"
These are surely not memory functions. And to say that "patterns" are
swapped in and out of "the stack" to "account" for current sensory input and
direct motor output is just plain arm-waving. You haven't spelled out a
single function of this model! Given 100 or 1000 memory boxes that swap and
juggle and account, I doubt that anyone could say what such a system is for.
What you've described so far doesn't sound like modeling to me.
Well, to begin you probably have to trace the inputs and outputs of each of
the boxes and see what is connected to what. We have general ideas about
this, but much remains to be done. And we certainly do know something
about what goes on in many of these boxes and using blood-flow and PET
techniques we know something about the combinations of boxes which are
active during various perceptual and cognitive tasks. And the paper Hays
and I did does put a little more flesh on that
"long-way-to-go-to-become-a-model."
Sure, what I've said is as deep into armwaving as the upper levels of your
stack. And when Rick Marken applauds Pythagoras for his contributions to
the logic level, that is completely vacuuous. But it is your kind of
vacuousness and so it goes on all the time on CSGnet and passes for
thought, or at least for creative messing around that some day might
eventuate in thought.
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William L. Benzon 518.272.4733
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What color would you be if you didn't know what you was?
That's what color I am.
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