from [Marc Abrams (2003.07.1143)]
On reflecting on my post yesterday, I could have been interpreted
differently the intended. This hopefully will clear up any ambiguity.
Bill, I don't disagree with your metaphor's. Your post yesterday on the
electric circuit is a nice one. But it still a metaphor. I have a very
difficult time with 'compensators', 'adders' and 'input functions' as
_Isomorphic_ and _Monomorphic_ to a human Central nervous system ( CNS ). I
believe that these modeling entities might very well be real _processes_
that take place,but I don't believe there are physical entities that
correlate to them one-to-one. I could be wrong. I have not seen any
plausible evidence to convince me otherwise. I cannot not understand why you
say you _never_ use metaphors. You just don't seem to like metaphors about
your metaphors.
Check out; http://groups.yahoo.com/group/cog_neuropsychology/
Marc
[From Bill Powers (2003.07.08.1024 MDT)]
Marc Abrams (2003.07.1143)--
I believe that these modeling entities might very well be real _processes_
that take place,but I don't believe there are physical entities that
correlate to them one-to-one. I could be wrong.
Yes, you could. For example, you object to the diagram of the wiring of the
tendon reflex on p. 83 of B:CP (that's what I think you meant). It was
adapted from information in a neuroanatomy text (repeated in a book by the
Nobel prize winner McMahon); all I did was add the identifications of the
parts of the standard control system to go with the elements of the real
system. Exactly what is wrong with it?
This is not the whole story; there are also stretch reflexes, static and
dynamic, as discussed on p. 89ff and as shown on page 91, Fig. 7.3.
Furthermore many of the signals shown are copied into other pathways where
they go to and come from opposing muscles, with reversed signs -- this
would make the diagrams messy so I stuck with the simplest versions (there
is no problem with incorporating the opposing muscles and their local
control systems if that becomes necessary).
Fig. 7.4 on page 92 shows the same arrangement in block diagram form, and
Fig. 7.5 is a condensed version which is used to represent the typical
first-order control system for limb control.
You seem to think this diagram is metaphorical, but it's as anatomical as
it is possible to get without drawing the system like Cajal sketching
through a microscope.
As nearly as possible, I designed the whole model, at all levels, so it
could be physically realized with neurons, though I don't know how the
perceptual functions do their computations at the higher levels (and
neither does anyone else). Many feedback loops similar to the one in Fig
7.3 have been found and physically traced in human and animal brains. So
what's your problem?
Bill P.
from [ Marc Abrams ( 2003.07.08.1741) ]
Yes Bill, I read my posts. I'm not sure anyone else does. Bryan, I apologize
for being a bit boorish, but I suggest you meet me half way and be a little
less sensitive to _how_ someone says something and _what_ they are trying to
say, and no I'm not leaving this list. In fact I have a small discussion
group on Yahoo I might have a link to CSGnet. I'm thinking about it.
[From Bill Powers (2003.07.08.1024 MDT)]
Marc Abrams (2003.07.1143)--
>I believe that these modeling entities might very well be real
_processes_
>that take place,but I don't believe there are physical entities that
>correlate to them one-to-one. I could be wrong.
Yes, you could. For example, you object to the diagram of the wiring of
the
tendon reflex on p. 83 of B:CP (that's what I think you meant).
No it's not. I object to the diagram on pg. 117 that Rick pointed me to.
Frankly I forgot about it. It's the descriptions _not_ in chap 7 but in Chap
8-12, In these chapters you try very hard to answer the age old
sensory-modality binding problem. You do an admiral job. But it just doesn't
work , for a number of reasons.
You seem to think this diagram is metaphorical, but it's as anatomical as
it is possible to get without drawing the system like Cajal sketching
through a microscope.
What is anatomical _are_ the diagrams you pointed out. But those diagrams
were about how motor control takes place, I have no argument with that. What
I want to know is why we move the way we do?
As nearly as possible, I designed the whole model, at all levels, so it
could be physically realized with neurons, though I don't know how the
perceptual functions do their computations at the higher levels (and
neither does anyone else). Many feedback loops similar to the one in Fig
7.3 have been found and physically traced in human and animal brains. So
what's your problem?
I think I just told you.
Marc