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I wrote in GP: "Have the Blue Brain project claimed anywhere that they aim for full human behaviour in 10 years?!" Answer: >>They predicted that an artificial

• jacquesm 17y ago
  Essentially the Blue Brain project is a study in emergent behaviour, simulate something and its behaviour should emerge. That is exactly what the project leader claims in the article linked, I don't think even they expect it to be human behaviour because that is limited to beings that are humans. The problem with the approach is that a simulation, by definition is not the real thing and that it will always end up being an approximation. Our most powerful computers could not simulate all the interactions between atoms in a 1x1x1 cm volume of solid matter, let alone all the matter in a chemical soup as complicated as the brain, and expect it to behave like one. So, this is also an approximation, only a very detailed one in spite of the researchers claims. They are still simulating neurons, one brain weighs about 1.5 Kg, it contains roughly on the order of 100 billion neurons, but it contains much more than just the neurons, and other cells in the brain could easily be crucial for its functioning. For example there are the 'glial' cells, which at least double the number of cells in any simulation that wants to take on the whole brain, the glial cells are part and parcel of brains all brains that we've looked at have them, they may be only there in a supporting role or they may end up being crucial. Recent studies suggest that these cells are not as simple and passive as we used to think and that they may have a more active role. That doesn't say it can't be done, it simply says that to stick a deadline on it is unwise. You should not make bold claims without the evidence to back it up. Essentially they are saying they are only 5 orders of magnitude away from simulating a brain in real time: The currently achieved milestone stands at 100 million neurons with 100 billion synapses 100 times slower than real-time, and that is assuming that the simulation model is indeed accurate enough to eventually lead to emergent behaviour, which to date has not happened. (And that would be the biggest news since the moon landings in terms of human achievement). Especially the growing up (which already starts in womb) is where the problems may be, we have absolutely no idea what it takes to bootstrap a brain. There may be more to it than we know about, in fact there probably is. Some theorists postulate the existence of firmware like code present in the DNA, there are many other even weirder theories, one of them may well be right. That would mean that we are simulating a bunch of hardware here, completely forgetting about the software required to run that hardware. Thanks for the explanation on hypoxia, I did not realize that the damage was always irreversible, even when the period without oxygen is short. Regarding the electro shock therapy, yes, that is true but it starts out assuming that the brains state is 'electrical', which it doesn't have to be at all. It could be chemical, it could be based on standing waves in the neural tissue, there are a great many ways to store state. For instance, one of the first computers that ever existed used standing waves in tubes filled with mercury to store its state. So until we know what that state is and how it is stored we will not know how to reset it reliably, nor will we know if it is possible to restore such a state once it has been 'lost'. 'Grand mal attacks' or seizures seem to have something to do with feedback loops within the brain, cycles where the end result sets the whole thing off once again. By necessity the brain has to contain many such potential loops and under normal conditions the feedback factor is kept in check, but with the right trigger pattern a series of self re-inforcing patterns can be established. edit: have a look here: http://www.its.caltech.edu/~dadgrp/research/poc/index.html http://www.its.caltech.edu/~dadgrp/research/poc/index.html there is a lot of interesting information in there, even though it is already old (10 years), the numerical data is still accurate.
  • berntb 17y ago
    >>Essentially the Blue Brain project is a study in emergent behaviour, simulate something and its behaviour should emerge. That is exactly what the project leader claims in the article linked, I don't think even they expect it to be human behaviour because that is limited to beings that are humans. First, the neuron models will probably still be adjusted in a century. (For instance, I've seen papers just a few years old which discussed how water really worked; that doesn't mean the understanding of water isn't very, very good.) Second, the brain researchers claim the research using new tools are going incredibly fast; see the claim in the interview of more information every year -- than in all of the 20th century! (So the article from ten years ago seems a bit outdated -- also, membrane receptors is a hard problem which just recently has even been touched. The Blue Brain people claims that they started with a molecular level emulation of the brain and then optimized it). (Also note that the Blue Brains researchers are aware of differences between individual cells because of history, etc. They aren't idiots.) >>The problem with the approach is that a simulation, by definition is not the real thing and that it will always end up being an approximation. Third, I have a hard time thinking of a better way to learn than research groups like Blue Brain encoding the present knowledge in computer models -- to compare against the real systems. No one expects the models to be perfect at once. Fourth, I trust the reviewers of the papers the Blue Brain research group writes to do basic reality checks, e.g. glial cell influences (when/if they are found to have a large influence). That would just be a factor of two in complexity, for parallel models like this, Moore's law works well... Fifth, chemistry is generally slow -- there can't be too much happening in thought/reaction, so most stuff in a neuron's work is "prebuilt"; no, not with memcached but with structural changes while learning. (There is heavy evolutional pressure to optimize for speed.) How good the emulations will be after refinement etc, is a much later question. But the researchers are evaluating (quite) modular systems "from below" -- they can't be too complex, because there just aren't enough building blocks (i.e. not enough genes). It is a hard problem, but I don't see a reason why it should be impossible to reach good models. That doesn't matter, what is more important is that the researchers think so, too. >>Regarding the electro shock therapy, yes, that is true but it starts out assuming that the brains state is 'electrical', which it doesn't have to be at all. Well, give an alternative mechanism that isn't reset by electrical shocks or cooling down to low temperature (as with some surviving drowning victims in cold water or some operations.) (The point of Grand mal attacks was that I wondered if they were reset mechanisms.) Note that changes in protein expression would be quite easy to find. And that human nerve cells aren't that different from other animals, which has been experimented quite heavily on. I can't have any ideas, here (also note the "fifth" point above.) Do you have anything except conjecture? I don't have the time to keep discussing, sorry. Edit: Cleaned up and was too hurried to mark it up carefully above. Sorry, if anyone ever reads this. :-)