Researchers at IBM have used a giant parallel computer to build a high fidelity model of a mouse brain that runs at 1/10th real time.
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!
Very cool stuff. I predict a future (perhaps 50 years hence?) when we can build realistic artificial human-like brains but still can't figure out how to imbue them with consciousness. (I'm a subscriber to the weak AI school of thought, which boils down to a belief that knowledgeable observers will always be able to distinguish between real and artificial intelligences.)