a thinking brain

Glen M. Sizemore gmsizemore2 at yahoo.com
Thu Jul 1 11:28:36 EST 2004


RS: To start off, let me say that I am not presenting a
> Grand-Theory-of-Everything, just a speculative thrust at how a brain
> composed of neurons might think, judge, and decide.
>
> GS: First, that's not a very good description of your posts. Second,
> what makes you think that I have not properly evaluated your
> position?.......both in terms of scope and particulars?

RS: I hope I never said that, or implied that. You read my post. What more
can I ask?

I say again, it is not a Grand-Theory-of-Everything. It is just a
simple thrust at how a mammalian brain thinks, judges, and decides. In
my simple model, a motor program hits the motoneurons, becomes a motor
act, reacts with the environment, and the result is evaluated by
sensory neurons as good or bad. The DNA defines good and bad.



GS: And, again, I'm saying that what you are describing is operant behavior
(but you are missing the "stimulus control component") and thus, your
assertion that what psychologists talk about is of no relevance is wrong.
The facts of operant behavior as uncovered by the experimental analysis of
behavior provide the facts that must be explained by a successful physiology
of behavior. Simple enough?


RS: I lump all motor programs under one word.motor acts. You say this is
not enough, I must elaborate these motor acts as behavior.



GS: No, I don't. I don't have any problem with the notion that the
activities of CPG's are gated. However, you have no mechanism for why such
spontaneous behavior comes to be so fluid and, seemingly, infinitely
fine-grained (especially in primates). Reinforcement blends and sequences
spontaneous behavior and makes it so the probability of such behavior
increases when stimuli, similar to those present (this is over-simplified)
when it was reinforced, reoccur. Further, each member of an operant response
class is different from all others, sometimes in fairly substantial ways. A
rat, for example may press with the left or right forelimb, or both. Rats
frequently seize the lever with one paw under and one on top. Any rat will
usually display all of these. In any event, my main point is that this is
the kind of stuff SOME psychologists investigate, and your claim that such
facts are irrelevant to a neurobiological understanding of behavior is
simply misinformed and sophomoric.

RS: I answer that I want simplicity. You say I cannot have it. Why can't
we leave it there so far as motor acts are concerned? I will lump it
and you will elaborate it.



GS: You are welcome to do whatever you want. Once again, I am specifically
responding to your erroneous statement concerning the alleged irrelevancy of
what is investigated by (at least some) psychologists.

RS: It is commonly said that the human brain is the most complicated
structure known to man. I say this is pure bullshit. I claim it comes
from someone (whose knowledge of the brain is limited to a profile
drawing of a cerebral hemisphere) who says, "I am incredibly smart.
Smarter than everyone I have met, and I, even I, cannot understand how
the brain works. It must be the most complicated structure known".

The neuroanatomist says that there is too a little complication there.
I say his difficulty is the classic one of inability to see a forest
for the trees. One hundred billion (or one trillion) neurons can be
lumped in a few structures. A filter that doubles as an associator, a
set of pattern controllers, initiators, generators, a thalamic
reticular nucleus to slow things down. We need at least two (there can
be more, of course) neurohormones to strengthen syanapses according to
the evaluation of good and bad.

We don't need all the molecular activity that makes up a cell. Cell
biology is beautiful. It is the pre-eminent science of this century,
but we just accept that all activity of an organism has a molecular
explanation. We continue to simplify.

Neural activity results in the initiation of a pattern generator that
produces a fictive motor program. If excitatory activity is
predominant in the thalamic reticular nucleus, the fictive motor
program is halted at the ventral anterior anterior-ventral lateral
complex. Signal energy continues to reverberate in the cerebrum and
the basal ganglia initiating a new pattern generator and a news
fictive motor program. If this new motor program together with the
signal energy present causes inhibitive activity to be predominant in
the TRN, the fictive motor program will proceed as an actual motor
program.

The motor program hits the motoneurons, a motor act ensues and reacts
with the environment. The result impinges on the sensory neurons and
the cycle repeats.

If the TRN continues to be active, pressure from the hypothalamus and
lower nuclei will force it to be inhibited and action will follow. It
may have a bad outcome but it will be forced except in a pathological
brain that cannot pass a fictive motor program.

This is a simplistic view of brain action. Why not criticize these
three paragraphs?



GS: I don't have much trouble with what you have said, as far as it goes.
And I even said that it might have some merit. What I continue to tell you
is that what you are talking about is operant behavior, and that the study
of operant behavior qua behavior sets the agenda for a successful physiology
of behavior.



"ray scanlon" <rscanlon at nycap.rr.com> wrote in message
news:363d693e.0407010452.421ca91f at posting.google.com...
> Glen M. Sizemore writes:





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