Spaun offers a rare window into the workings of the human brain

The world’s largest working brain model helps show how brains break, and how we can fix them.

By Tenille Bonoguore

Communications & Public Affairs

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Chris EliasmithThe brain is an amazing and complex thing, according to Waterloo professor Chris Eliasmith. He should know. He’s building one.

A team led by the Canada Research Chair in Theoretical Neuroscience has created the world’s largest functional brain model. Their research was published Nov. 29 by Science.

Called Spaun, the model can see, remember, think and write using a mechanical arm. Right now, Spaun and its environment are housed in a computer. So Spaun lives in a simulated world with simulated physics. Still, Spaun uses only its brain to understand images it sees, and “move” its virtual arm. In short, it uses the same processes that your brain does to pick up a cup of coffee.

“It has been interesting to see the reactions people have had to Spaun. Even seasoned academics have not seen brain models that actually perform so many tasks. Models are typically small, and focus on one function,” says Eliasmith, who is jointly appointed to the departments of philosophy and systems design engineering, and cross-appointed to computer science at the University of Waterloo.

Currently, other large-scale brain models (over a million neurons or so) do one thing — mimic lots of neurons. Spaun does that too (it has 2.5 million neurons), but more importantly, it is constructed so those neurons actually think about patterns it encounters and make things happen in its environment (and you can watch videos of it working).

To build it, Eliasmith and his team had to create specific brain systems, using methods from a number of different fields, including engineering, computer science, biology, philosophy, psychology and statistics.

“The reason that the Spaun model is so compelling, is that it brings all of this work together,” he said.

“Human cognition isn’t interesting because we can recognize visual patterns … move our arms in an integrated way … [or] solve a particular task or puzzle. It’s interesting because we can do all of this with the same brain, in any order, and at any time.”

Model brain, real impact

Spaun might be theoretical, but its potential impact is entirely human.

By simulating the impact of different drugs, or how the brain copes with problems such as stroke or Alzheimer's disease, researchers can gain better insights into what many consider to be a final frontier of science: Ourselves.

“There are not only deep philosophical questions you can approach using this work — such as how the mind represents the world – but there are also very practical questions you can address about the diseased brain,” Eliasmith said.

“I believe that critical innovations are going to come from basic research like this. I can’t predict what specific industry or company is going to use this work or how — but I can list a lot that might.”

The success of Spaun doesn’t mean humans are being replaced any time soon, though.

Despite the model being a significant advance, “people are enormously more complicated. [Spaun] is nowhere near as intricate or sophisticated as human brains,” he said. “It’s miles away.”

Watch for: Chris Eliasmith’s book “How To Build A Brain” will be published this fall by Oxford University Press.