a thinking brain

ray scanlon rscanlon at nycap.rr.com
Thu Jul 1 07:52:55 EST 2004


Glen M. Sizemore writes:
 
> 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?

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.

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

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.

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?

ray



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