Neuro boffins mimic brain action

A breakthrough in electronic engineering could revolutionise computing, and lead to radical improvements in hardware designed to aid the deaf and blind.

Researchers at MIT and Lucent Technologies have created an electronic circuit which mimics the biological circuitry in the cerebral cortex.

"Neuroscientists have found that cortical feedback seems to operate in a way that is unfamiliar to today's electronic designers," said H. Sebastian Seung, assistant professor of computational neuroscience at MIT. "We set out to mimic this novel mode of operation in an unconventional electronic circuit."

The circuit is made of artificial neurons that communicate via artificial synapses. (Biologically speaking, a synapse is the junction between axon terminals and neurons, across which nerve impulses pass.)

Nonetheless, the researches recommend caution when comparing the electronic and neural circuits. Recent neurophysiological experiments suggest that the brain is neither digital nor analog. For example, an approaching car is processed digitally in that it is either a car or not a car. But we perceive an analog, continuous stream of information about its colour, dimensions, position, and speed as well.

Rahul Sarpeshkar, a post-doctoral fellow, suggests the hybrid analog-digital nature of the brain may be fundamental to its computational efficiency. He says the electronic world is evolving "more and more towards mixed analog-digital computation as the brain has already done. However, the brain's mixed-signal circuits combine analog and digital functions in a much more intimate way than is done in the electronic world."

This research means there are much better ways for analog information to be processed electronically that have previously been possible... hence the potential for improving technology for hearing aids and sight augmentation.

Sarpeshkar thinks that this kind of research will revolutionise computing through its combination of the digital advantages of programmability, noise immunity and divide-and-conquer processing with the analog advantages of efficiency.®