Spaun, an artificial brain has 2.5 million neurons, compared to the human brain's 100 billion neurons Lizzie Gill

Chris Eliasmith, the director of the University of Waterloo's Centre for Theoretical Neuroscience, Canada, is trying to build a brain. Eliasmith's artificial model, Spaun, currently has just 2.5 million neurons to the human brain's 100 billion. But unlike more computationally demanding simulations, which have run for only a few simulated seconds, it's actually capable of doing something with them.

"There's been an attitude of scale for scale's sake," Eliasmith explains. "But for us, the focus was discovering how neurones can be organised to produce behaviours, such as solving simple intelligence tasks."



Spaun is much closer to actual brain structure than a typical artificial neural network, yet it still lacks biological plausibility. So this year, Eliasmith's team finished upgrading the model's highly simplified artificial neurons from just two equations per neuron to 90.

"That's allowed us to start simulating the effects of drugs and diseases," he explains. "If you have a hypothesis about the mechanism of Alzheimer's, you could test that, and if you have a drug that you think would have some particular impact, you can simulate it to see the effects on the brain and its behaviour."