Re: Symbolic AI: Why Marvin Minsky and Curt Welch Are Out to Lunch


Traveler wrote:
On 25 Jul 2006 04:27:33 -0700, "bob the builder"
<brulsmurf@xxxxxxxxxxx> wrote:

Traveler wrote:
...
The basis of my hypothesis is at once religious, philosophical,
scientific and experimental. I will not go into my religious views
here since this is not the proper forum for it.
MAGIC PEOPLE VOODOO PEOPLE :P
Phlosophically, I
approach all problems (scientific or otherwise) from a yin-yang
complementarity POV. Examples of complements are sensors/effectors,
event onset/event offset, etc... The scientific basis of my approach
to signal separation comes from a paper written by Henry Markram et al
in 1997. It is titled "Regulation of Synaptic Efficacy by Coincidence
of Postsynaptic APs and EPSPs".

http://www.nbb.cornell.edu/neurobio/linster/BioNB420/pdfs/markram_etal_1997.pdf

Essentially, Markram found that the efficacy of synapses impinging on
a pyramidal neuron in the sensory cortex is strongly increased if they
fire about 10 ms before the target neuron fires. If they fire at any
other time, they are slightly weakened.

Discrete signal separation is not rocket science. It is a simple
probabilistic process. Although Markram does not explain in his paper
how the neurons are triggered to fire in vivo (he conducted in vitro
experiments), I hypothesize that a sensory cortex neuron fires only if
one of its input synapses (the successor) fires immediately after
(within 10 ms in the human brain) a predecessor synapse. The neuron
works as a gate or filter that opens to let some signals through while
blocking the others. Its function is simple: a specific signal within
a sensory stream is channelled down a specific path.

In my own experiments, I have found that a 10 to 1 correlation ratio
between predecessor and successor is good enough to capture all
significantly correlated signals from two related streams.

EHm, two related streams, ehm. Can i see the situation as following:
( A practical example)

U U <- two sensors in the eye. (Sensor A and B)
| | <- synaptic terminals
U <- a neuron ( neuron C )
| <- has to fire if something moves from left to
right(as seen by the eye)

Now neuron C has to delay the path from itself to sensor A so that the
signals from sensor A and B reach C at the same time when something
moves from left to right with a certain speed. Now neuron C fires if
something moves from left to right.

Is this an (ill posed) example of two related streams?

Well yes, one can do it that way, by using path delays. My
understanding is that, in the brain, the "delay" (if you wish to call
it that) takes place within the target neuron, not in the path. The
taqrget neuron is essentially primed by the predecessor synapse and a
primed neuron fires if a second signal arrives on another stream
shortly afterwards.

What this
means is that the predecessor must fire at least once for every ten
firings of the successor synapse. I have religious reasons for
choosing this ratio but, again, that's a different story for another
place and another time. In the brain, the interval and the correlation
ratio are determined by genetics. For examples, I read somewhere that
visual experiments have shown that the temporal interval is much
shorter in bees and bats.

2. Once signals are separated, the next task is to fuse them. This is
done by using special neurons that detect concurrency. Of course,
since the sensory space is uncertain, these neurons will fire even if
a fraction of its inputs did not fire concurrently.

And again, how are the signals selected for fusion and how are the fusion
"neurons" tuned? What controls the setting of the fraction?

Signal fusion is the simplest thing of them all. It is basically a
Hebbian process. Synapses (these may be chosen at random) that fire
together are strengthened while the others are weakened and eventually
severed. I use a 20 to 1 correlation ration for these neurons for
reasons that I will not go into.

20 to 1. 95%. ehr something from a statistics course is coming up.

Sorry, I have no idea what you mean by the above sentences.

Louis Savain

Hey Louis, I'm raggin yer ass here, but what about that wonderful
idea ov yers 'bout using visuals instead of semantics?

yers si

.

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