Mainstream medicine is making increasing use of electronics inside the body, deploying implanted gadgets both to measure internal conditions and to provide stimulating jolts of electricity to nerves and muscles. But turning a human into a proper cyborg will require many minuscule devices that can be scattered throughout the body. As a step toward that goal, a team of bioengineers has built speck-size wireless electrodes that can be affixed directly to nerves—and that may one day be nestled inside the brain.

The engineers from the University of California, Berkeley, implanted one mote of what they call “neural dust” inside an anesthetized rat, and demonstrated that the electrode could record signals from the rat’s sciatic nerve and wirelessly transmit the information. This experiment was a proof of concept, says Jose Carmena, who co-led the research at UC Berkeley’s Center for Neural Engineering and Prostheses, where he is codirector. If the neural dust can be adapted for the human body and brain, doctors could have an intimate new interface with the human nervous system.

But first, it had to work in a conked-out rat.

To power the neural dust, a transducer outside the animal’s body emits ultrasound vibrations that pass through skin and tissue. When the sound waves reach the implanted mote,…[Read more]