Artificial brain mimics human abilities and flaws

Canadian scientists have created the world’s largest functioning brain model which produces complex behaviour and performs almost as well as humans at simple tasks.

Described in Science, the Semantic Pointer Architecture Unified Network (Spaun) is a computer model of the human brain created by Professor Chris Eliasmith, Director of the Centre for Theoretical Neuroscience, and colleagues from the University of Waterloo in Canada. It consists of 2.5 million virtual neurons; fewer than the average human brain which comprises around 86 billion, but enough to recognise lists of numbers, do simple arithmetic and reasoning problems.

"This is the first model that begins to get at how our brains can perform a wide variety of tasks in a flexible manner—how the brain coordinates the flow of information between different areas to exhibit complex behaviour," says Eliasmith.

Spaun is presented with a sequence of visual images in eight separate tasks. It then processes the information and decides which action to take. Spaun can recognise and remember numbers written in different handwriting and can copy them using a mechanical arm. Additionally, Spaun can answer questions about complete number series after seeing examples.

While the tasks are simple, they capture many features of neuroanatomy and physiology. The most surprising feature of Spaun according to the researchers is that it has human-like flaws. Examples include having trouble remembering lists of numbers that are too long, and being better at recalling numbers at the start and ends of lists. Spaun also hesitates before answering questions, just as humans do.

Eliasmith says that Spaun could provide a powerful platform for testing hypotheses about how the human brain works.

"In related work, we have shown how the loss of neurons with aging leads to decreased performance on cognitive tests," said Eliasmith. "More generally, we can test our hypotheses about how the brain works, resulting in a better understanding of the effects of drugs or damage to the brain."

Chris Eliasmith’s book “How To Build A Brain” will be published next year by Oxford University Press

http://www.youtube.com/watch?v=P_WRCyNQ9KY

A large scale model of the functioning brain