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Wednesday, December 02, 2009

100 neural net cycles to produce consciousness?

This interesting article presents data indicating that it takes around half a second for an unconscious visual percept to become conscious (in the human brain)...

This matches well with Libet's result that there is a half-second lag between unconsciously initiating an action and consciously knowing you're initiating an action...

(Of course, what is meant by "consciousness" here is "consciousness of the reflective, language-friendly portion of the human mind" -- but I don't want to digress onto the philosophy of consciousness just now; that's not the point of this post ... I've done that in N prior blog posts ;-)

My Chinese collaborator ChenShuo pointed out that, combined with information about the timing of neural firing, this lets us estimate how much neural processing is needed to produce conscious perception.

As I recall, the firing of a single neuron's action potential takes around 5 milliseconds ... It takes maybe another 10-20 milliseconds after that for the neuron to be able to fire again (that's the "refractory period") .... Those numbers are not exact but I'm pretty sure they're the right order of magnitude...

So, the very rough estimate is 100 cycles in the neural net before consciousness, it would seem ;)

This fits with the view of consciousness in terms of strange attractors ... 100 cycles is often enough time for a recurrent net to converge to into an attractor basin ...

But of course the dynamics during those ~100 cycles is the more interesting story, and it's still obscure....

Is it really an attractor we have here, or "just" a nicely patterned transient? A terminal attractor a la Mikhail Zak's work, perhaps? Etc.

Enquiring minds want to know! (TM)

5 comments:

Anonymous said...

Forget c++.. port your programs over to Google's new replacement language, 'go', which is a c/c++ for today's machines, using all we have learned in 30 years!

IBloom said...

Seems like 'go' needs a little time to prove itself. (As well as get a debugger.) Besides, hyper graph traversal is about the same in any language.

Anonymous said...

If Consciousness were a strange (or Lorenz) attractor, and matter/energy was what was "attracted" to it, then what would form at the boundary would be called "Life" at the edge of Chaos???
So, Life is the Interface between Consciousness and Matter???
No wonder people have been arguing/oscillating between Objective/Subjective POV's since the beginning of Time :)

flamoot said...

i'm pretty stoked. the electronic neurons i'm working with now are a lot faster than that and may be more ideal in other ways as well. i think what brains and nervous systems are is this highly evolved implementation of some fungal philosophy, the fungal body or mycelium which is networked and probably conscious. fungi could be an extrasolar artifact so neurons might be high technology indeed. when we simulate their bare functionality then maybe we can expect one of those electronic ones to be worth many biological ones, considering the overhead in the physical substrate

my 2c

flamoot

Diego said...

No one neuron can fire more than 100 times by your estimate, but using your numbers you could have signals shoot back and forth between pools of neurons way more times
pools A,B, neurons A1,A2,A3... in A likewise for B
A1 -> B1 -> A2 -> B2 ....

All the while, every neuron is integrating signal.