[ExI] Blue Brain Project
jonkc at bellsouth.net
Mon Feb 8 21:55:14 UTC 2010
On Feb 8, 2010, Richard Loosemore wrote:
> Markram is NOT, as many people seem to assume, developing a biologically accurate model of a cortical column circuit. He is instead developing a model that contains neurons that are biologically accurate, down to a certain level of detail
That is a legitimate concern, and it's true we don't know everything there is to know about neurons, but we know a lot, and this is by far the best simulation of a large number of neurons ever made. And remember, most of the things that neurons do have nothing to do with thought, they are just the routine (though fabulously complex) housekeeping functions that any cell needs to do to stay alive.
> So, to anyone who thinks that a randomly mode of an i86 computer chip in which all the wiring was replaced by random connections would be a fantastically interesting thing, worth spending a billion dollars to construct, the Blue Brain project must make you delirious with joy.
But the boosters of biology are always pointing out that 3/4 of a i86 chip is a completely worthless object, while a dog with only 3 legs is not immobile, he can still limp around. Markram wants to incorporate the same robustness into a computer program, and I think he has a fighting chance of pulling it off.
> Markram's entire project, then, rests on his hope that if he builds a randomly wired column model, the model will "self-assemble" and do something interesting.
Markram says that already his simulation is acting in ways that remind him of the ways real neurons act. OK maybe he's talking Bullshit, but I'm very impressed that in his very next utterance he shows us a way to prove him wrong. He says that in the next 2 to 3 years he will be able to synthesize an entire rat brain. He also says he can link that computer model to a mechanical rat. If that robot rat moves at random then he has failed. If the mechanism moves in more interesting ways then the man is onto something.
> Further, he ignores the possibility that the self-assembly mechanisms are dependent on such factors as (a) specific wiring circuits in the column, or (b) specific wiring in outside structures (subcortical mechanisms, for example) which act as drivers of the self-assembly process. To couch this in terms of an example, suppose the biology causes loops of ten neurons to be set up all over the column, with the strength of synapses around each loop being extremely specific (say, high, high, low, high, high, low, high, high, low, low). Now suppose that the self-organizing capability of the system is crucially dependent on the presence of these loops. Since Markram is blind to exact wiring he will never see the loops. He certainly would not see the pattern of synaptic strengths, and he probably would never notice the physical pattern of the ten-neurons loops, either.
My neurons are not making the proper connections. If you put a gun to my head I couldn't tell you what the hell you're talking about.
> As far as I can tell, Markram's only reason to believe that his model columns will self-assemble is ... well, just a hunch. If his hunch is wrong, he will have built the world's most expensive white-noise generator.
If he fails it will be a heroic failure, if he succeeds it will be the the most important work ever done, not just scientific work, work in general.
> On Sun Ben Zaiboc wrote:
> I know I mentioned these links a few days ago, but it's worth repeating.
> Noah Sutton is making a documentary:
> There's a longer video that explains what he's up to.
> The Emergence of Intelligence in the Neocortical Microcircuit
Thanks agin Ben, yet more great stuff!
John K Clark
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