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Simulating 1 second of real brain activity takes 40 minutes and 83K processors

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Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#91

Post by vidarh »

aa0 wrote: post #37
ceejayoz wrote: post #9

Earlier quoted context omitted.

If I'm a simulation, I'd prefer to exist and have a legal right to continue doing so.

If you were a simulation, you might not have free will. To even propose that you'd have a decision beyond state-machine-dynamics is a world away.

I've yet to see a convincing definition of "free will" that makes any sense as anything other than an abstraction on top of determinism or randomness. To propose that we have any ability to make decisions beyond state-machine-dynamics possibly with some randomness sprinkled on top, is totally nonsensical to me.

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#92

Post by beloch »

If Moore's law were to continue to hold, this would mean the same simulation could operate in real-time on an 83K processor cluster in approximately 25 years or on one processor in about 50 years. Of course, this simulation is 1% of the neurons that a human brain has, and I don't know if scaling up to a full-brain would be linear (This probably depends on the average length of axons in the brain.). This completely unrealistic estimate also assumes no improvements in algorithms, etc..

Perhaps a more interesting question is whether or not the brain can really be simulated by a classical computer at all. If quantum mechanics plays a role in the function of the brain we will need a quantum computer to do the job. A classical simulation of a quantum brain would be a very odd beast indeed! It might exhibit behavior that seems like intelligence but somehow falls short.

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#93

Post by wikiburner »

beloch wrote: post #92

If Moore's law were to continue to hold, this would mean the same simulation could operate in real-time on an 83K processor cluster in approximately 25 years or on one processor in about 50 years. Of course, this simulation is 1% of the neurons that a human brain has, and I don't know if scaling up to a full-brain would be linear (This probably depends on the average length of axons in the brain.). This completely un…

Roger Penrose has theorized the brain relies on quantum effects, but it seems to have been as discredited as something currently unfalsifiable can be discredited.

http://en.wikipedia.org/wiki/Quantum_mind

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#94

Post by ck2 »

beloch wrote: post #92

If Moore's law were to continue to hold, this would mean the same simulation could operate in real-time on an 83K processor cluster in approximately 25 years or on one processor in about 50 years. Of course, this simulation is 1% of the neurons that a human brain has, and I don't know if scaling up to a full-brain would be linear (This probably depends on the average length of axons in the brain.). This completely un…

Or by 2020 they make an asic chip that emulates a brain cell and it computes 10x faster than realtime.

Massive array at 8nm and there's your positronic brain.

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#95

Post by Sven7 »

pygy_ wrote: post #44

These attempts at brain simulation perplex me to no end. Simulating a lump of tissue is definitely useful, it's when they start talking about simulating a complete brain that I get lost. A brain doesn't happen overnight. It is the result of a long developmental process encompassing embryology, learning and experience acquisition. How do they plan to wire the whole thing? Micro- and macroscopic connections are well un…

Yup...people thought the Wright brothers should stick to building bicycles too. I mean how can a bicycle repairman replicate a mechanism that nature took a million years to develop in a bird? It was ridiculous. Couple years later they were watching them fly around in the air.

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#96

Post by teahat »

jfoutz wrote: post #34
deletes wrote: post #15

Earlier quoted context omitted.

To correctly model a cell you would need to simulate every atom and there are about 10^11 to 10^14 (!) of them in a single cell. I think an interesting number would be how many atoms does it take to simulate one atom reasonably well. Then you could get correct results for some ( really ) small biological functions.

What would you get from simulating both hydrogen atoms and the oxygen atom that you wouldn't get from simulating plain old water? The vast majority of a cell is just water, seems like you could cut your complexity in half with that abstraction. I'm no molecular biologist, so i'll happily agree if you say there are some fraction of water molecules broken down, or formed by various cellular processes, but that must be…

At an atomic level, water plays critical roles in very small quantities and understanding these role requires detailed simulations. See this recent paper [1] for an example of how water molecules affect potassium channel inactivation, a key process in cardiac electrophysiology and other areas.

That's not to say that you can't get useful results by treating solvent as a continuum (or even ignoring it entirely), they'll just have a different kind of explanatory power.

[1] http://www.sciencedaily.com/releases/2013/07/130728134055.ht...

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#97

Post by cLeEOGPw »

ibudiallo wrote: post #88

Maybe we are simply taking the wrong approach. How many gears from a mechanical computer does it take to simulate a micro processor? If we were to one day to closely simulate the brain, I am sure the method will not involve computers as we know them today.

> How many gears from a mechanical computer does it take to simulate a micro processor?

Imo brains themselves are like mechanical gears compared to the potential of processor.

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#98

Post by pygy_ »

hannibal5 wrote: post #48
pygy_ wrote: post #44

These attempts at brain simulation perplex me to no end. Simulating a lump of tissue is definitely useful, it's when they start talking about simulating a complete brain that I get lost. A brain doesn't happen overnight. It is the result of a long developmental process encompassing embryology, learning and experience acquisition. How do they plan to wire the whole thing? Micro- and macroscopic connections are well un…

They use it to understand brain. So they wire it like the brain is wired. If they simulate cortex, they wire arrange it into cortical columns (size of each column is between 50,000 and 100,000 neurons and there is over two million of them). Those columns have many different layers and neuron types. Understanding how cortical columns and minicolumns work is very important.

You made my point regarding small scale simulation, but completely missed the rest.

> So they wire it like the brain is wired.

As if anyone knew how to do that. Even assuming that you can do both accurate micro-tractography and extract cell-by cell epigenetic information out of a single column, you'd still be missing other cricial information like individual synaptic strength.

I'm not talking about cortico-thalamic connections (required to model epilepsy) inter-columnar connections, and whatever regulation happens in the white matter.

Relying on the probability distribution of connections as a crude approximation is useful, but far from the real deal.

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#99

Post by luikore »

beloch wrote: post #92

If Moore's law were to continue to hold, this would mean the same simulation could operate in real-time on an 83K processor cluster in approximately 25 years or on one processor in about 50 years. Of course, this simulation is 1% of the neurons that a human brain has, and I don't know if scaling up to a full-brain would be linear (This probably depends on the average length of axons in the brain.). This completely un…

It's Penrose's view that a brain is quantum, but this paper http://arxiv.org/pdf/quant-ph/9907009v2.pdf shows human brain is more classical than quantum.

Maybe the simulation algorithm is the thing that needs improvement. Some day one finds a way to reduce the complexity an order of magnitude, then the era of human brain is over.

Re: Simulating 1 second of real brain activity takes 40 minutes and 83K processors

#100

Post by npatrick04 »

This has been done before with a full human brain scale model in 2005. It took 50 days on 27 processor for that simulation. It's always good to have more research being produced, but this linked article is a bit short on information.

http://izhikevich.org/human_brain_simulation/Blue_Brain.htm

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