Vladimir Nesov wrote:
On Fri, Nov 21, 2008 at 1:40 AM, Richard Loosemore <[EMAIL PROTECTED]> wrote:
The main problem is that if you interpret spike timing to be playing the
role that you (and they) imply above, then you are commiting yourself to a
whole raft of assumptions about how knowledge is generally represented and
processed. However, there are *huge* problems with that set of implicit
assumptions .... not to put too fine a point on it, those implicit
assumptions are equivalent to the worst, most backward kind of cognitive
theory imaginable. A theory that is 30 or 40 years out of date.
Could you give some references to be specific in what you mean?
Examples of what you consider outdated cognitive theory and better
cognitive theory.
Well, you could start with the question of what the neurons are supposed
to represent, if the spikes are coding (e.g.) bayesian contingencies.
Are the neurons the same as concepts/symbols? Are groups of neurons
redundantly coding for concepts/symbols?
One or other of these possibilties is usually assumed by default, but
this leads to glaring inconsistencies in the interpretation of
neuroscience data, as well as begging all of the old questions about how
"grandmother cells" are supposed to do their job. As I said above,
cognitive scientists already came to the conclusion, 30 or 40 years ago,
that it made no sense to stick to a simple identification of one neuron
per concept. And yet many neuroscientists are *implictly* resurrecting
this broken idea, without addressing the faults that were previously
found in it. (In case you are not familiar with the faults, they
include the vulnerability of neurons, the lack of connectivity between
arbitrary neurons, the problem of assigning neurons to concepts, the
encoding of variables, relationships and negative facts ...... ).
For example, in Loosemore & Harley (in press) you can find an analysis
of a paper by Quiroga, Reddy, Kreiman, Koch, and Fried (2005) in which
the latter try to claim they have evidence in favor of grandmother
neurons (or sparse collections of grandmother neurons) and against the
idea of distributed representations.
We showed their conclusion to be incoherent. It was deeply implausible,
given the empirical data they reported.
Furthermore, we used my molecular framework (the same one that was
outlined in the consciousness paper) to see how that would explain the
same data. It turns out that this much more sophisticated model was
very consistent with the data (indeed, it is the only one I know of that
can explain the results they got).
You can find our paper at www.susaro.com/publications.
Richard Loosemore
Loosemore, R.P.W. & Harley, T.A. (in press). Brains and Minds: On the
Usefulness of Localisation Data to Cognitive Psychology. In M. Bunzl &
S.J. Hanson (Eds.), Foundations of Functional Neuroimaging. Cambridge,
MA: MIT Press.
Quiroga, R. Q., Reddy, L., Kreiman, G., Koch, C. & Fried, I. (2005).
Invariant visual representation by single-neurons in the human brain.
Nature, 435, 1102-1107.
-------------------------------------------
agi
Archives: https://www.listbox.com/member/archive/303/=now
RSS Feed: https://www.listbox.com/member/archive/rss/303/
Modify Your Subscription:
https://www.listbox.com/member/?member_id=8660244&id_secret=120640061-aded06
Powered by Listbox: http://www.listbox.com
