the liver and the brain

dan michaels feedbackdroids at yahoo.com
Sat Sep 4 11:56:10 EST 2004


rscanlon at nycap.rr.com (ray scanlon) wrote in message news:<363d693e.0409040231.207c0adb at posting.google.com>...
> Dan Michaels writes:
> 
>  > r norman writes:
>  
> > > The question is:  how much of the improvement of performance after
> > > birth is due simply to the continued development and maturation of the
> > > nervous system, that is, to the further elaboration of the genetic
> > > program that was left incomplete at birth, and how much to actual
> > > learning and experience?  My guess is that for many truly altricial
> > > animals both aspects are important and it is a very difficult
> > > experimental question to sort out which component is more important.
> > > More likely, in many mammals (especially primates and humans) the
> > > genetic program is preconfigured to require learning as an integral
> > > component.
> 
> Lord knows, I have said things in this debate that I wish I hadn't,
> but I will
> open my big mouth again. I sincerely apologize to anyone whose
> feelings were hurt.
> 
> In my opinion, possibly we should ask ourselves whether we wish to
> assign causal powers to the soul. If we wish to differentiate between
> "further elaboration of the genetic program" and "actual learning",
> this may be the case.
> 


No, we're far beyond this now. In cybernetics, we assign "causal"
influences to recurrent feedback loops - ie to on-going [in the
temporal sense] neural processes which are modulated by new inputs.
This takes assignment of "specific" time and place right out of the
mix. The usual arguments, regards prime movers ultimately going back
to immateriality [soul, etc] is a result of what Bateson calls
"lineal" thinking. In most arguments regards causality, you will
easily observe that the participants on both sides are lineal
thinkers.
===============


> These are not idle words. Stephen Jay Gould, in his great battle with
> the creationists, would distinguish between the two magisteria, that
> of science and that of religion. There is no final answer, but we can
> always take temporary positions.
> 
> I would say that if the subject is the scientific explanation of the
> brain, then we couldn't distinguish between "genetic program" and
> "learning". But this is only my temporary position. Outside the
> laboratory, I am a religionist. ("Lab" is a figure of speech. All I
> have is an electronics workbench in the basement.)
> 


Well, nature vs nurture arguments have been going on for what - 100 or
200 years now - and no doubt they'll being going on for many more.
=================


> > BTW, I'm sure your answer is pretty much "the" answer. But actually
> > there might be 3 parts to look at - genetics, development [ie, as in
> > finetuning of the type Hubel+Wiesel studied in lid-sutured animals],
> > and learning [as in finally learning to distinquish a cat from a
> > lion]. My personal working-hypothetical model pretty much allocates
> > the latter learning parts to areas beyond the 30+ visual centers of
> > the cortex, which mainly function as visual pre-processors with more
> > or less specific functions in each. The outputs of these form the
> > basis of what is stored in later [association] areas. At least this
> > model is easy to conceptualize [and to potentially model], if not
> > wholy accurate biologically.
> 
> I say this is basic. Is the distinction between lion and cat a
> question of molecular biology or is it not? You pays your money and
> you takes your choice.
> 

No, I meant it as a question of survival. The animal/child that cannot
distinquish between the two gets eaten.
=============


> In my humble opinion, when Hubel and Wiesel first stumbled on the
> truth that the cortical cell they had probed responded to a line
> segment rather than a spot, a great divide in human thought occurred.
> (Actually, that first cell was a complex cell that responded to a
> moving line segment.) This was not shared by all. There is a letter in
> which Marr referred to H&W's "silly little spots of light". Marr
> wanted the cell to respond to a computation of the entire visual
> scene, or at least a good portion of the scene.
> 


Actually, this is a very good criticem, whether or not it was Marr
referring to H+W, or someone else. In actuality, it's my understanding
that H+W were some of the first to go to something *beyond* simply
flashing punctate points of light - which is what had been done for
many years beforehand in primate visual studies. H+W used visual
stimuli which had much greater significance to the animals - and
legend has it that they got the idea from Lettvin et al:

http://www.ai.mit.edu/people/phw/6xxx/lettvin.html

OTOH, it is a good criticism that, just like studying animal behavior
in a strictly narrow situation, H+W were not studying cell properties
in animals which were using their visual systems on a normal sense.
Therefore, a lot is necessarily being missed. OTOH, the then-current
technology made this difficult to do, at best. Likewise, today.

>From a cybernetics viewpoint, what H+W were doing was probably
something akin to "opening the feedback loop". So, they were measuring
something of importance, but not the entire thing in its normal
context.
==================



> I bridle at the word "stored". Synapses are altered, but nothing is
> "stored".
> 


Whatever.



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