10 ms·
Simulating 1 second of real brain activity takes 40 minutes and 83K processors
- anigbrowl 13y agoUnfortunately, that's only for a number of cells equivalent to 1% of a human brain. A full brain's worth of simulation would take 2.5 days....although that much is probably not necessary. It will fall soon enough, though.
- pervycreeper 13y agoThe thought that we are maybe two decades away from having the computing power to simulate a human brain in realtime (and much more than that subsequently) is astounding, even in this age of technological wonder.
- cabalamat 13y agoAssuming (1) it's parallelisable (2) this is an accurate enough similation, and (3) a whole human brain is 100 times bigger, we'd need 406083k*100 processors which is about 20 billion. We could do it now (hardware-wise), if we really wanted to.
- pervycreeper 13y agoAdmittedly, I was just spitballing from the parent poster's numbers. But the idea that brain simulation is not that far off still seems plausible given those extra considerations.
- mischanix 13y agoIf each processor draws down 50 Watts, 20 billion of them would draw 1 TW. The US uses on average ~3 TW across every power source (including e.g. combustion engines).
- coldarchon 13y agoadd another decade until we have the right software then ..
- visionscaper 13y agoSo it will take about 26.6 years before we can simulate a brain in real time, only considering Moore's Law. (Calculated this without pen and paper using my iPhone calculator, so somebody should check this ;) )
- pervycreeper 13y agoPretty much. http://wolfr.am/13dDALd http://wolfr.am/13dDALd
- visionscaper 13y agoHa! Thanks for checking!
- gst 13y agoOnly if you assume that there won't be any other advances in technology that will speed up simulating a brain (such as more specialized processors). Look at genetic sequencing. It was really hard to get from 0% to 1% of sequenced human DNA. But sequencing the remaining percent happened much faster, and nowadays the cost for is exponentially decreasing (which means that soon you will be able to buy your sequencing kit at your local supermarket for a few dollars). I would be very surprised if it took us another 26.6 years to simulate a brain in real-time. Maybe half of that time. And a few years later you will be able to cheaply backup your own brain in the cloud in case you have an accident.
- oh_teh_meows 13y agoI'm not certain if that extrapolation you made of the time it takes to simulate a brain at the same abstraction level is valid. You're assuming the computation cycles needed will scale linearly, which might not be true considering that the brain is a network of neurons, where each neuron has a high number of in/out links to many other neurons. Consider the case where you take n seconds to simulate n neurons. Now add another neuron with connections to perhaps n/2 existing neurons. You'll have to iterate over each in/out edge of that neuron. Since adding just one neuron increases the time by a non-constant factor, the resources needed would increase more than just linearly. All this of course depends on the abstraction model, and I admit I know nothing about it.
- anigbrowl 13y agoIt's not my extrapolation, it's from the TFA, yes they assumed lineaar scaling.
- oh_teh_meows 13y agoOh I see. Sorry. Should have read TFA closely :-/
- IvyMike 13y agoAt what point does this become unethical (if ever)? Before you answer, please consider how certain you are that you are not a simulation. Edit: I don't know the answer, and there probably is a large gray area. But I do know this starts to make me uncomfortable the more accurate it gets. Time to go reread Egan's Axiomatic again, I guess.
- csallen 13y agoEven if you are a simulation, would you prefer not to exist? What, really, is the difference between reality and a perfectly-executed simulation? It's hard to condemn one without condemning the other.
- ceejayoz 13y agoIf I'm a simulation, I'd prefer to exist and have a legal right to continue doing so.
- aa0 13y agoIf 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.
- tensor 13y agoYou might not have free will as a meat brain.
- vidarh 13y agoI'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.
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- jjjeffrey 13y agoDoes anyone know what it means to simulate brain activity? Is the brain being emulated in any meaningful way? Or is it just modeling the physical behavior of neurons?
- marcosdumay 13y agoFrom the article, those were simulation of our neurons, randomly connected. The intention was to test the machine and software.
- foobarbazqux 13y agoTo put this claim in perspective, we are still unable to simulate a single cell by modeling everything we know from biochemistry, even if we ignore molecular dynamics. Mostly this is because we don't know what many genes and the proteins they encode do. This matters, for example, if we want to simulate neuronal plasticity or the effect of antidepressants. We're an incredibly long way from a full simulation, which would also require integration with the rest of the nervous system.
- gwern 13y ago> To put this claim in perspective, we are still unable to simulate a single cell by modeling everything we know from biochemistry, even if we ignore molecular dynamics. Mostly this is because we don't know what many genes and the proteins they encode do. To me, this mostly shows that naive beliefs about difficulty aren't really accurate ('but it should it harder to simulate a brain than a cell, because it's bigger right!'). But of course, progress is being made on simulating cells: http://lesswrong.com/lw/drk/paper_simulation_of_a_complete_cell/ http://lesswrong.com/lw/drk/paper_simulation_of_a_complete_c... It's a high-level enough model that you can do it with only 1 core per cell.
- foobarbazqux 13y agoSure, but that's also for a bacterial cell. We have 50 times as many genes and you can't easily culture humans on a Petri dish for experimentation. A single gene can take years of work to understand. Yes, you can simulate anything if you abstract away enough. But if the goal is a convincing replication, you'll need to include lots of intracellular effects. In the end, I believe that practical simulation of a whole brain that you can have a conversation about its existence with is more difficult than the development of quantum computing powerful enough to break all existing crypto. The work is still interesting, if only because it pushes the limits of what we can do. But I might want to start with an ant brain.
- Dylan16807 13y agoWhy does it show that the belief isn't accurate? This isn't simulating a brain, it's simulating the connections in a brain and pretending the neurons are about as complex as wires. That is a model that is possibly correct, but there's certainly no evidence it's correct.
- frozenport 13y agoAre these processors or processing elements (PEs)?
- pothibo 13y agoYes we are very far away from the human brain on many levels. However, I don't like this kind of article because it doesn't make sense on the software level. Mathematically, we could figure out how much computing power we would need to match the human brain (24 bytes per synapse * number of synapse, etc). I think I would be more interested in what was the specific of their experiment. - What kind of software were they running? - Was the software bug-free(yeah right)? - Was the software optimized? - Caching?
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- pygy_ 13y agoThese 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 understood, it is the so-called meso-scale (in between) that is troublesome. There will never be a non-destructive way to do extract the information of a live brain, and I'm not sure there will ever be a way to extract it at all. The current methods[0] allow to extract either the wiring or the genes expression. [0] http://www.brain-map.org/ http://www.brain-map.org/
- hannibal5 13y agoThey 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.
- pixie_ 13y agoEach neuron is growing, making decisions about it's environment, reacting to a multitude of neurotransmitters with a mulititude of complex reactions. Deciding where are when to make a new connection. If each node is a little computer system how do we even begin to emulate its probably extensive and convoluted 'programming.'
- pygy_ 13y agoYou 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.
- bhitov 13y agoI found the article misleading. Real brain activity was not simulated. From the press release (emphasis mine): "The nerve cells were randomly connected and the simulation itself was not supposed to provide new insight into the brain"
- Xcelerate 13y agoThe title statement is almost meaningless. It would be better just to say "simulating reality takes a LONG time". My research is in molecular dynamics. I simulate systems up to 1 billion atoms on Kraken & Titan. HUGE approximations are made in simulating these systems, but depending on what exactly it is you're studying, these simulations still provide useful results. That is the key to all these studies: how well does your approximation reproduce whatever it is that you're attempting to model? In some cases, very well. For instance, I'm not going to get exact energy levels of a large system, but the system will qualitatively evolve in the same fashion that the experimental system does (which then guides the experimental counterpart to the research). I don't know the details of this brain simulation, but there is certainly some aspect of it that is not being reproduced anywhere close to real-life, and hopefully this isn't what they're interested in (and I'm sure they know that, but I don't think the article author does). The very best simulations of reality that we can perform handle at most just a few H/He/C atoms. And an issue called the fermion-sign problem means that the computational power necessary to simulate larger systems scales exponentially with the number of particles. Unfortunately what that means is -- short of developing quantum computers (which are polynomial order for the sign problem) -- we aren't ever going to simulate more than a few atoms with near-perfect accuracy, and certainly nothing like a human brain. EDIT: Didn't mean for my comment to sound so negative. Obviously, the researchers know exactly what they're doing. I was just trying to dispel the impression that we're close to simulating the human brain.
- marcosdumay 13y agoIf we have a reliable model for how synapses fire, we can simulate the brain. Whatever problems quantum mechanics impose on molecular simulation is not relevant, the same way that you don't need to simulate the nucleons on your molecules even if you need precise energy measurements.
- dekhn 13y agoGenerally, the people doing brain simulations like to claim that they can use a massively reduced representation (little more than a graph model that pushes signals around with some constants) and yet, somehow, the simulation is inherently capable of reproducing something complex about thought. I'm not sure how they get to this conclusion, but it's a massive reductionism. It would be nice if it were true- it would mean that for a reasonable expenditure, we could build a machine that, basically, "thought" and had a "mind" and we could convince ourselves that it was "living" much like we think of other humans. To date nobody has come up with a really compelling disproof that they are more or less correct- thought and mind seem to be best explained as "emergent behavior of a complex system". Now, whether can we bootstrap a thinking mind by running complex simulations on computers remains to be seen. I'd like to believe there is some interesting physics going on in brains we can't simulate with straightforward physical models, but there really isn't any good evidence for that.
- SeanDav 13y agoI would imagine that the analogue nature of the brain is going to always entail a lot of approximation on simulation. I am not sure you could even accurately simulate even 1 neuron. Disclaimer: this is completely out of my field - just a layman speculating.
- mentos 13y agoThis assumes that the neuron is the level of granularity that we need to simulate? Is there any research on what other chemical/electrical interactions might be necessary to simulate the brain?
- omarchowdhury 13y agoYeah, you need to simulate an entire universe as well. ;)
- psadri 13y agoHow many Moore law doublings before it is real time? Seems like ~23 generations or ~35 years. Of course, if you leave out the bits constantly thinking about sex, we might get there a lot faster :)
- nfoz 13y agoWhere's the source code?
- kingkawn 13y agoRecent research has shown glial cells, the uncelebrated insulator of the axon, in fact provide significant chemical signaling and modulation to the process of neural activity. Only phenotypical changes have been observed, it's not understood yet. Suffice to say that computational limits aside, we still couldn't simulate a brain because we wouldn't know what to make.
- ibudiallo 13y agoMaybe 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.
- cLeEOGPw 13y ago> 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.
- beloch 13y agoIf 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.
- wikiburner 13y agoRoger 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 http://en.wikipedia.org/wiki/Quantum_mind
- thelamest 13y agoIt's not like there is a conspiracy against Penrose, there is just a prevailing feeling (which I for one subscribe to) that: "computation via quantum mechanical processes is irrelevant to explaining how brains produce thought, contrary to the ongoing speculations of many theorists. First, quantum effects do not have the temporal properties required for neural information processing. Second, there are substantial physical obstacles to any organic instantiation of quantum computation. Third, there is no psychological evidence that such mental phenomena as consciousness and mathematical thinking require explanation via quantum theory. We conclude that understanding brain function is unlikely to require quantum computation or similar mechanisms." (http://watarts.uwaterloo.ca/~pthagard/Articles/quantum.pdf http://watarts.uwaterloo.ca/~pthagard/Articles/quantum.pdf)
- wikiburner 13y ago
- npatrick04 13y agoThis 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 http://izhikevich.org/human_brain_simulation/Blue_Brain.htm
- Tloewald 13y ago1 second of the brain activity we know about.