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Scientists are getting closer to the dream of creating computer systems that can replicate the brain.

Researchers at the Massachusetts Institute of Technology have designed a computer chip that mimics how the brain's neurons adapt in response to new information.

Such chips could eventually enable communication between artificially created body parts and the brain.

It could also pave the way for artificial intelligence devices.

There are about 100 billion neurons in the brain, each of which forms synapses - the connections between neurons that allow information to flow - with many other neurons.

This process is known as plasticity and is believed to underpin many brain functions, such as learning and memory.

The MIT team, led by research scientist Chi-Sang Poon, has been able to design a computer chip that can simulate the activity of a single brain synapse.

Activity in the synapses relies on so-called ion channels which control the flow of charged atoms such as sodium, potassium and calcium.

The 'brain chip' has about 400 transistors and is wired up to replicate the circuitry of the brain.

Current flows through the transistors in the same way as ions flow through ion channels in a brain cell.

"We can tweak the parameters of the circuit to match specific ions channels... We now have a way to capture each and every ionic process that's going on in a neuron," said Mr Poon.

Neurobiologists seem to be impressed.

It represents "a significant advance in the efforts to incorporate what we know about the biology of neurons and synaptic plasticity onto ...chips," said Dean Buonomano, a professor of neurobiology at the University of California.

"The level of biological realism is impressive," he added.

The team plans to use their chip to build systems to model specific neural functions, such as visual processing.

Such systems could be much faster than computers which take hours or even days to simulate a brain circuit. The chip could ultimately prove to be even faster than the biological process.