When I first saw this on the BBC web site I thought it looked exciting - maybe the first "upload". But on closer inspection it seems to be less impressive. There is an extremely brief report on what they did, which looks like merely simulating a large number of neurons on a supercomputer, without any detailed biological architecture as far as I can tell and no mention of glial interactions. Simulating a lot of neurons is an achievement, and may be a precursor to uploading.
A while back I did some preliminary image processing on the BranMaps data sets, and it is possible to automatically identify cell bodies and their processes. Of course this is still a long way from being able to simulate what's going on in detail, since the images tell you nothing about the chemistry. Some examples are as follows: http://farm1.static.flickr.com/45/360938915_827b42d493_o.jpg http://farm1.static.flickr.com/137/360938913_6b7ffb9cbe_o.jpg These are the denizens of layer 6 of the primate cortex. Strange looking creatures indeed. Not at all like the neat rows of transistors that would be found on an integrated circuit, or the highly idealised models from computer science. The green blobs are cell bodies. I exchanged a few emails with the folks at BrainMaps, and the next major step which they anticipate is scanning the brain slices using lasers to get even higher accuracy. This should permit, in the not too distant future (mainly dependent upon availability of large quantities of hard disk space and a suitable customised scanner), complete reverse engineering of the physical architecture of the brain. There are difficult practical problems, such as being able to align multiple brain slices with an accuracy sufficient for the fine processes (dendrites and axons) to line up. Based upon these discussions I think the first brain upload, for pure physical architecture at least, may not be as far away as many might suppose. For practicality I expect the first creature to be uploaded will be some small animal, like a mouse or rat. On 28/04/07, J. Storrs Hall, PhD. <[EMAIL PROTECTED]> wrote:
In case anyone is interested, some folks at IBM Almaden have run a one-hemisphere mouse-brain simulation at the neuron level on a Blue Gene (in 0.1 real time): http://news.bbc.co.uk/2/hi/technology/6600965.stm http://ieet.org/index.php/IEET/more/cascio20070425/ http://www.modha.org/papers/rj10404.pdf which reads in gist: Neurobiologically realistic, large-scale cortical and sub-cortical simulations are bound to play a key role in computational neuroscience and its applications to cognitive computing. One hemisphere of the mouse cortex has roughly 8,000,000 neurons and 8,000 synapses per neuron. Modeling at this scale imposes tremendous constraints on computation, communication, and memory capacity of any computing platform. We have designed and implemented a massively parallel cortical simulator with (a) phenomenological spiking neuron models; (b) spike-timing dependent plasticity; and (c) axonal delays. We deployed the simulator on a 4096-processor BlueGene/L supercomputer with 256 MB per CPU. We were able to represent 8,000,000 neurons (80% excitatory) and 6,300 synapses per neuron in the 1 TB main memory of the system. Using a synthetic pattern of neuronal interconnections, at a 1 ms resolution and an average firing rate of 1 Hz, we were able to run 1s of model time in 10s of real time! Josh ----- This list is sponsored by AGIRI: http://www.agiri.org/email To unsubscribe or change your options, please go to: http://v2.listbox.com/member/?&;
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