MIT chip mimics human brain

The analogue chip has about 400 transistors and, according to Chi-Sang Poon, a principal research scientist in the Harvard-MIT Division of Health Sciences and Technology, could help neuroscientists learn more about how the brain works. It could also be used, he says, in neural prosthetic devices such as artificial retinas. The chip is designed to stimulate the activity of a single brain synapse – a connection between two neurons that allows information to flow from one to the other. Its transistors mimic the activity of different ion channels in the brain, with current flowing through them in an analogue fashion, instead of a digital one. A gradient of electrical potential drives current to flow through the transistors just as ions flow through ion channels in a cell. "We now have a way to capture each and every ionic process that's going on in a neuron," explained Poon. He believes the new chip represents a significant advance in the efforts to incorporate what is known about the biology of neurons and synaptic plasticity onto cmos. The MIT researchers now plan to use the chip to build systems to model specific neural functions, such as the visual processing system. Such systems, says Poon, could be much faster than digital computers and even the brain itself.