Steve Richfield wrote:
Richard,
Broad agreement, with one comment from the end of your posting...
On 11/20/08, *Richard Loosemore* <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
Another, closely related thing that they do is talk about low level
issues witout realizing just how disconnected those are from where
the real story (probably) lies. Thus, Mohdra emphasizes the
importance of "spike timing" as opposed to average firing rate.
There are plenty of experiments that show that consecutive
closely-spaced pulses result when something goes "off scale", probably
the equivalent to computing Bayesian probabilities > 100%, somewhat akin
to the "overflow" light on early analog computers. These closely-spaced
pulses have a MUCH larger post-synaptic effect than the same number of
regularly spaced pulses. However, as far as I know, this only occurs
during anomalous situations - maybe when something really new happens,
that might trigger learning?
IMHO, it is simply not possible to play this game without having a close
friend with years of experience poking mammalian neurons. This stuff is
simply NOT in the literature.
He may well be right that the pattern or the timing is more
important, but IMO he is doing the equivalent of saying "Let's talk
about the best way to design an algorithm to control an airport.
First problem to solve: should we use Emitter-Coupled Logic in the
transistors that are in oour computers that will be running the
algorithms."
Still, even with my above comments, you conclusion is still correct.
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out of date.
The gung-ho neuroscientists seem blissfully unaware of this fact because
they do not know enough cognitive science.
Richard Loosemore
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agi
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