AI, NN, and CNS

[Steve Hanson]

Jim:

It is true that connectionism and AI have tended to compete in
terms modeling.  Both however require something to model.
I think your view on neuroscience's relation to connectionist
modeling is somewhat narrow and a bit shrill.
AI researchers have tended to focus on a vauge notion of
"intelligence".  Connectionists have tended to be less
opportunistic about the modeling piece parts they
have chosen but have modeled just about anything standing still. 
Is it all biologically motivated?--heavens no!  Why should
it be?  Is any of it?--of course (there are several
good volumes around documenting this: "Neural Modeling", Koch & Segev, 1989; 
"Conectionist Modeling and Brain Function", Hanson & Olson, 1990;
"Connectionism and Neuroscience", Gluck & Rumelhart, 1990 and several
others I forget their titles..sorry). But computational modeling can 
occur at any level of interest and be productive and valid.   
That it does not model certain cells and circuits or jim`s favorite cells 
or circuits does not invalidate the oppportunity for such modeling to 
happen and have continuity with other relevant system level modeling.  It's
a two-way street, both modelers and experimentalists have a responsibility
to constrain and enlighten each other--if they don't then
complaints like yours have a self-perpetuating flavor to them.  
The brain's a big place and as far as I can tell has plenty of
room for lots of system level speculation.  Connectionist Modelers are
studying all sorts of (yes even wooly ones) system level interactions
and possible mechanims for various kinds of function.  Sejnowski and
Churchland had a nice Science article where they attempt to lay out
possible relations between "simplified" and "realistic" neural
models.  I wrote a paper that appeared recently in Behavioral and 
Brain Science on what I thought was the relation between AI and 
connectionism--many people responded in kind.  I refer you to
those papers for more detail in order to keep this conversation
short.  I think it is important at this point not to polarize
this issue by either assuming there is only one unique way
to characterize neural computation or worse that the details
of the brain don't matter.

	Steve