"Then I thought the only way people are going to believe me is if I demonstrate it," says the University of Waterloo neuroscientist.

So Eliasmith's team built Spaun, which was billed Thursday as "the world's largest simulation of a functioning brain."

Spaun can recognize numbers, remember lists and write them down. It even passes some basic aspects of an IQ test, the team reports in the journal Science.

Several labs are working on large models of the brain- including the multi-million-dollar Blue Brain Project in Europe - but these can't see, remember or control limbs, says Eliasmith.

"Right now very large-scale models of the brain don't do anything," he said in an interview.

His Waterloo team took a different approach, using computers to simulate what goes on inside the brain, similar to the way aircraft simulators mimic flight.

The clever creation is the first to bridge what Eliasmith calls the "brain-behaviour gap."

Spaun, which stands for Semantic Pointer Architecture Unified Network, has 2.5 million simulated neurons organized into subsystems to resemble the prefrontal cortex, basil ganglia, thalamus and other cognitive machinery in the brain. It also has a simulated eye that can see, and an arm that draws.