From: tedwards@src.umd.edu (Thomas Grant Edwards)
Subject: Cognitive Science 
Organization: Systems Research Center, Maryversity of Uniland, College Park
Date: Fri, 14 Aug 1992 20:22:49 GMT

In article <1992Aug13.221810.3475@pony.Ingres.COM> jpk@Ingres.COM (Jon Krueger) writes:
>Thomas Grant Edwards writes:
>> studies where rats' minds are altered physically or chemically,
>> and maze run times are used as a measure of performance

>Performance of what?

Well, let me explain cognitive science.  In CogSci, one builds up models
of cognitive prcoesses one is studying.  Often they are simple
box and arrow charts of information flow from different cognitive 
sub-processes, occasionally they are more detailed to show areas of the
brain, or known communicative codings between the sub-processes.

Cognitive Science works to figure out the best model of cognitive
processes.  This occurs through two main methods

1)  Recording experiments, where you look at different parts of the
    brain using electrodes, PET scans, and you could even include
    neuroanatomy here.
2)  Damage experiments, where damage from natural causes or artificially
    inflicted on the brain destroys a sub-process, or at least slows
    it down.

One such example is the dual pronunciation route.  The cognitive theory
is that there are two ways for a person who is presented with visual
language stimuli to verbally pronounce the word.  One method is by
"looking up" the word in a word->pronunciation corpus, the other is
by breaking the word down into its individual phonemes.

How does one validate this theory?  Well, first you study normal 
people.  They can pronounce words and non-words at about the same speed
(i.e. word: cat, hat; non-word: fot, holad, etc.)  Obviously, non-words
are not in the word->pronounciation corpus, while the words are.

Then you examine people with brain damage (due to strokes, shrapnel, cancer,
etc.)  You find there are populations of people with brain damage
which have a real hard time pronouncing non-words (takes longer),
but easily pronounce real words.  And of course, there is also a population
which has difficulty with pronouncing any word, but the damage which
causes this problem is not neccessarily both pronounciation guides 
being damaged, but could be a visual or spoken language problem where
the doule streams of information rejoin up and down "river" from
the pronounciation.  And obviously, if your non-word system is working,
you can always read real words with it, even if your real word corpus
is down.

So what does this mean for our poor little rats?  
Well, we could be testing for whether localized damage due to
cutting up parts of the brain damages the skills in maze running
(memory being key here).  We could also be testing whether fetal brain
tissue applied to cortex increases performance of maze-running 
after the rat has had its memory damaged (and shown lowered performance
on maze-running).  The same could apply to a host of neuropharamcuticles
aimed at memory improvement.  

There is also still lots of room for recording experiments from
rats when they run mazes, such as the kind that lead to the theory
of place cells (cells which apparently respond to the place a rat is,
and perhaps its orientation). 

Also, I can imagine rat maze running as a test of conditioning (i.e.
we do something to the rat so it doesn't respond to conditioning itself,
to test learning processes.  Also we could be testing the rat's ability
to respond to conditioning stimuli.
 
-Thomas