Neurological research

[Gabriel 921214 20:55 CST]
(Powers same date)

Remember, mainframe software was not
made to serve people; people were made to serve mainframe
software.

Agreed. Missing feedback 3 terminal controller some place. Gang of
3 busy in search of same. Finding an awful lot of lesions in
corporate consciousness. Seriously Bill, you and I agree too often for
it to be possible for us to disagree on fundamentals. Small
unweighted Hamming Distance. But weights are perhaps large for
Aristotelian attributes where we disagree. Seems to me this should
be called strong but isolated disagreement. Delta functions at
a few isolated bits integrate up to significant heat at times,
but not large distance all the same.

Your point about using information about the brain is a good one.
I did a good deal of that in writing BCP. In fact when I went to
work at the VA Research Hospital in Chicago, I was full of
ambitions, with the Northwestern University Medical School (and
library) right across the street. I thought good, I can just go
through all the neurological literature and look up what the
various parts of the brain do, and build the model around that. I
was soon disillusioned.

Perhaps it really is true that the real world is just very complicated
and the great simplifying principles only go so far in the face of
a channel where we still have less than perhaps 1 millionth or one
billionth of the complete system specification. But that in no way
diminishes the significance of the simplifying principles. Without
them, we would even more badly drowned in data we don't understand.

As you say, brain researchers have found a good deal of
interesting material without using PCT, more in recent years with
improvements of technology. The problem is not with the
technology, however. It's with the concepts of behavior against
which neurological findings are compared.

Fundamental truth. Without a good abstraction, you just have a
pile of unorganised data. Without a taxonomy you can't even
begin to communicate about the attempt to abstract. Linnaeus
done good!! Hugh Dingle, who taught my wife her courses in
ecology and animal behaviour used to talk about the field
naturalist phase of scientific theories.

When you stop to think about it, neurological findings are ALWAYS
based on SOME theory of behavior. Without any theory of behavior,
all you have is a record of lesions in various parts of the brain
and some recordings of spikes and potentials from electrodes in
anatomically, but not functionally, known areas. You see the
theory of behavior not in the findings about the brain, but in
the descriptions of external correlates of brain activity.

This is what I might call the "Symmetry Theory" that we don't
have yet. The meta-Gestalt of neuroanatomy.

"Naturally, the lesion method can only be as good as the finest
level of cognitive characterization and anatomical resolution it
uses. In other words, the method's yield is limited by:
  1. The sophistication of the neurophysiological testing or
experimentation with which anatomical lesions are correlated.
  2. The sophistication of the theoretical constructs and
hypotheses being tested by the lesion probes.
  3. The degree of sophistication with which the nervous tissue
is conceptualized ... 4. The anatomical resolution of the methods used." (p.
9)

At risk of igniting burned out flames, some place in the first few
pages of one or another of H. Weyl's books on Group Theory he says
"All the real work is down in the mud and the blood."

From a modeler's point of view, the sophistication of
neurophysiological testing and experimentation is not very high.
In fact, evaluations of what is wrong with the behavior of a
person with a brain lesion tends to rely on subjective and rather
crude classification of symptoms rather than models of brain
function.

A rather good description of the work of a field natural historian.
The fact that clinical medicine a) can sometimes fix what hurts,
and b) probably has the world's biggest collection of incompletely
correlated facts within its' collective perspective, does not
make it a mature science. I suppose I'm both fortunate and unfortunate
in being inclined towards mathematics and physics. The physics at
least is perhaps closer to being a worked out vein of gold. The
mathematicians can take comfort however in being always incomplete.

................................

And so on and so on. What's going on is nothing more than an
informal assessment of superficial aspects of behavior to see if
the patient can do all the things that normal people do, and in
the familiar way. An atmosphere of formality is generated by
using Latin terms -- alexia for inability to read, prosopagnosia
say that the person "has" alexia, "has" prosopagnosia, etc.
..........................

But professional jargon has a useful place besides telling those
who don't have union cards to stay out of the discussion - an
instruction eliciting hostility from all of us factual omnivores.
It conjures up to those "in the know" a very large card index of
shared experience. And when a really neat theory like PCT
satisfactorily abstracts part, but not all of that card index,
the owners of the card index find their livelihoods threatened.
If you can abstract all of the index then you win the pot, and
the previous owners of the intellectual territory are eventually
unemployed. But, as the historians of science point out, only
after the generation holding both the card index and the levers
of power have all died or retired. The ecological purpose of
intellectual warfare. Some time appropriate around April 1st,
I'll publish on the net a taxonomy of academia invented by an old
friend whom I have not seen for almost 40 years - Margaret di Menna,
who originated the classification the day after the party to celebrate
her Ph. D. If there are any readers out there in Kiwiland who know
her, please say the taxonomy is still in use.

..........................
Such reports of what's wrong are analogous to the report a
technologically naive person makes to an auto mechanic: "it makes
a funny noise sometimes; it pulls to the left; the acceleration
is sluggish above 30 miles per hour; the steering wheel shakes."
When the mechanic sets out to fix the problem, he doesn't look
for a funny noise or a pull to the left or a center of
sluggishness or a steering-wheel shake. Those are just the
symptoms, outcomes, consequences. The mechanic understands how
the car works, so he looks for a hole in the exhaust pipe, a
tight wheel bearing, a malfunctioning carburetor, or anunbalanced tire. He
doesn't say, "Oh, you car has odd-noisia, or
dextromobilia, or accelerotardia, or manipulo-oscillia" and go
look up the recommended treatment in a big thick book. He reasons
out what might underlie the symptoms on the basis of the theory
of operation of an automobile, and that theory tells him what is
REALLY wrong with the car. That's what a good theory of behavior
does for you, when it's tied to the actual functions of the
device. It lets you reason your way to the layers of organization
that underly superficial symptoms.

Bill, I think it's sometimes hard to distinguish between a malfunctioning
carburettor, and accelerotardia if you don't know what a carburettor
is. And the problem is very difficult when the mechanic is still
trying to articulate what a carburettor is, but in trade school jargon,
not neurophysiological jargon.

Your previous paragraph is going to come back to haunt you the next time
you complain about triangulation in Kanerva spaces.

Bill, I think I've pulled your leg hard enough so I should stop before
exceeding the elastic limit so far that a perceptual feedback circuit
causes you to seize a 2x4 and beat me around the head.

But all in fun, and I hope in a good cause. Perhaps I should publish
the taxonomy on Jan 1st. CSGNET is the most wonderful colony of
boffins I've ever had the privelege of associating with, and between
us perhaps one day we'll predate on the buzzards who review papers
submitted to the trade union journals.

Tom Baines has an interesting theory of the origins of revolutions
- like the 1917 Soviet one, rather than the scientific variety. But I
am inclined to think it holds for the scientific ones too. I don't
remember whether my comment about the bloodless wars in academia was
made on-line or off-line. But just like the chicken run, it's hell
being at the bottom of the pecking order. Scientific territory is just
as subject to ambition and militarism as any other kind. Only the
dictators have no guns and no police force, just the threat of no
tenure.

        Sincerely, and with affection for all my fellow boffins.
        Sic Itur ad Astra, and nil Bastardio Carborundum.

                John Gabriel

[From Bill Powers (921214.1045)]

Mark Olson (921214.1010) --

You may have less frustration in sending if you set your right
margin to 65 and be sure you have a hard carriage return at the
end of each line. If you send a long string without a return you
can overrun a buffer in your mainframe, which will cause the
transmission to be rejected. Remember, mainframe software was not
made to serve people; people were made to serve mainframe
software.

ยทยทยท

-------------------------------------------------------
Your point about using information about the brain is a good one.
I did a good deal of that in writing BCP. In fact when I went to
work at the VA Research Hospital in Chicago, I was full of
ambitions, with the Northwestern University Medical School (and
library) right across the street. I thought good, I can just go
through all the neurological literature and look up what the
various parts of the brain do, and build the model around that. I
was soon disillusioned. Maybe the information was there
somewhere, but if so it was like a card index that someone had
dumped on the floor, stirred, and put back at random. You'll find
some neurological references in BCP, but not nearly as many of
them as I had hoped to accumulate. I did make a note about Hubel
and Weisel. Basically, however, my ambitious neurological project
was a bust.

As you say, brain researchers have found a good deal of
interesting material without using PCT, more in recent years with
improvements of technology. The problem is not with the
technology, however. It's with the concepts of behavior against
which neurological findings are compared.

When you stop to think about it, neurological findings are ALWAYS
based on SOME theory of behavior. Without any theory of behavior,
all you have is a record of lesions in various parts of the brain
and some recordings of spikes and potentials from electrodes in
anatomically, but not functionally, known areas. You see the
theory of behavior not in the findings about the brain, but in
the descriptions of external correlates of brain activity.

This problem has not escaped brain researchers. Mary brought home
a book on lesion research recently: Damasio, H. & Damasio, A. R.;
_Lesion Analysis in Neurophysiology_ (New York: Oxford University
Press,1989). In the introduction, D&D say

  "Naturally, the lesion method can only be as good as the finest
level of cognitive characterization and anatomical resolution it
uses. In other words, the method's yield is limited by:
   1. The sophistication of the neurophysiological testing or
experimentation with which anatomical lesions are correlated.
   2. The sophistication of the theoretical constructs and
hypotheses being tested by the lesion probes.
   3. The degree of sophistication with which the nervous tissue
is conceptualized ... 4. The anatomical resolution of the methods used." (p.
9)

From a modeler's point of view, the sophistication of

neurophysiological testing and experimentation is not very high.
In fact, evaluations of what is wrong with the behavior of a
person with a brain lesion tends to rely on subjective and rather
crude classification of symptoms rather than models of brain
function.

A large part of testing for neurological deficits consists of
presenting stimuli to patients and recording how they respond. If
you hold up a card with a picture, or point to an object, can the
subject utter its name? If you tell the subject to point to your
finger, then the subject's own nose, then the finger again and so
forth, do the movements seem normal, and are the end-points
accurately located? Do the movements seem retarded or uneven? Are
there tremors or oscillations? Can the patient repeat back a
spoken sentence, read a written sentence, follow spoken or
written directions to do something? Can the subject name colors
correctly, in all parts of the visual field? Can the patient
speak the correct name of a seen person? Can the patient sing
when so commanded? Is reading speed impaired? Is grammar correct?
Can the patient understand and/or generate sentences of normal
length? In general, is the response competent and appropriate to
the stimulus?

And so on and so on. What's going on is nothing more than an
informal assessment of superficial aspects of behavior to see if
the patient can do all the things that normal people do, and in
the familiar way. An atmosphere of formality is generated by
using Latin terms -- alexia for inability to read, prosopagnosia
for inability to recognize persons, constructional apraxia for
inability to make well-formed sentences (I think). If you strip
away the Latin, what you have left is just a subjective
description of what the person can't accomplish that normal
people can. The main thing the Latin terms do is to allow you to
say that the person "has" alexia, "has" prosopagnosia, etc.

These deficits give some clues as to what various parts of the
brain accomplish. But they don't tell us what those parts of the
brain DO -- that is, what functions are carried out in these
particular networks that normally result in the externally
visible consequences that we call reading, pointing, naming, and
so forth.

Such reports of what's wrong are analogous to the report a
technologically naive person makes to an auto mechanic: "it makes
a funny noise sometimes; it pulls to the left; the acceleration
is sluggish above 30 miles per hour; the steering wheel shakes."
When the mechanic sets out to fix the problem, he doesn't look
for a funny noise or a pull to the left or a center of
sluggishness or a steering-wheel shake. Those are just the
symptoms, outcomes, consequences. The mechanic understands how
the car works, so he looks for a hole in the exhaust pipe, a
tight wheel bearing, a malfunctioning carburetor, or anunbalanced tire. He
doesn't say, "Oh, you car has odd-noisia, or
dextromobilia, or accelerotardia, or manipulo-oscillia" and go
look up the recommended treatment in a big thick book. He reasons
out what might underlie the symptoms on the basis of the theory
of operation of an automobile, and that theory tells him what is
REALLY wrong with the car. That's what a good theory of behavior
does for you, when it's tied to the actual functions of the
device. It lets you reason your way to the layers of organization
that underly superficial symptoms.

Even the interpretation of neural connections themselves is
conditioned by the background theory:

"In the new approach, subjects' behavioral responses are not just
linked to the stimuli that eventually triggered them, but are
connected to mind processes and representations that handled the
stimulus and generated the responses according to some mechanism.
The investigations no longer shy away from formulating hypotheses
about those mechanisms and attempting to test their validity,
indirectly, by measuring external responses." (p. 14).

The brain is a maze of connections. If you are under the
impression that stimuli cause responses, you will select a path
through this maze that connects inputs to outputs, and ignore all
other connections (even while noting, in passing, that they
exist). You'll stick an electrode somewhere the in the middle of
this network and present a stimulus to the senses and look for a
response from the electrode. Then you'll try to stimulate that
spot and see what response results. If you get a response you'll
say that you've traced out an S-R path from input to output. If a
reference signal entered into this path somewhere, you'd never
find it.

There's no way NOT to apply a model when you're doing brain
research. The normal accepted model is an S-R model. This way of
thinking about behavior limits what brain research can discover
-- or at least which of its discoveries it can purport to make
some sense of.

A neurologist who understood PCT would do different kinds of
investigations and see different meanings in the findings. Most
certainly, such an investigator would use different methods of
assessing deficits. The investigator would be trying to find out
not just what this person can control and can't control, but how
the parameters of control have changed from those shown in normal
people. Quantitative experiments would replace informal
subjective classifications of symptoms. Perception and action
would not be considered separately, but as a closed-loop system.
The whole approach to diagnosis would change. Instead of just
going through lists of behaviors that a normal person should be
able to produce, the researcher would be building up a picture of
the functions that enable such superficially-observable behaviors
to be seen. The specific quantitative deficits would point to
specific underlying brain functions like perception, comparison,
and output that would produce such symptoms if operating in a
particular defective way.
I think that PCT would revolutionize neuropsychological research.
-----------------------------------------------
Best,

Bill P.