Commanding machines using the brain is no longer the stuff of science fiction. In recent years, brain implants have enabled people to control robotics using only their minds, raising the prospect that one day patients could overcome disabilities using bionic limbs or mechanical exoskeletons.
But brain implants are invasive technologies, probably of use only to people in medical need of them. Instead, electrical engineer Todd Coleman at the University of California at San Diego is devising noninvasive means of controlling machines via the mind, techniques virtually everyone might be able to use.
His team is developing wireless flexible electronics one can apply on the forehead just like temporary tattoos to read brain activity.
"We want something we can use in the coffee shop to have fun," Coleman says.
The devices are less than 100 microns thick, the average diameter of a human hair. They consist of circuitry embedded in a layer or rubbery polyester that allow them to stretch, bend and wrinkle. They are barely visible when placed on skin, making them easy to conceal from others.
The devices can detect electrical signals linked with brain waves, and incorporate solar cells for power and antennas that allow them to communicate wirelessly or receive energy. Other elements can be added as well, like thermal sensors to monitor skin temperature and light detectors to analyze blood oxygen levels.
Using the electronic tattoos, Coleman and his colleagues have found they can detect brain signals reflective of mental states, such as recognition of familiar images. One application they are now pursuing is monitoring premature babies to detect the onset of seizures that can lead to epilepsy or brain development problems. The devices are now being commercialized for use as consumer, digital health, medical device, and industrial and defense products by startup MC10 in Cambridge, Mass.
Electronic telekinesis? Digital telepathy?
In past studies, Coleman’s team found that volunteers could use caps studded with electrodes to remotely control airplanes and flew an unmanned aerial vehicle over cornfields in Illinois. Although the electronic tattoos currently cannot be used to pilot planes, “we’re actively working on that,” Coleman says.
These devices can also be put on other parts of the body, such as the throat. When people think about talking, their throat muscles move even if they do not speak, a phenomenon known as subvocalization. Electronic tattoos placed on the throat could therefore behave as subvocal microphones through which people could communicate silently and wirelessly.
"We’ve demonstrated our sensors can pick up the electrical signals of muscle movements in the throat so that people can communicate just with thought," Coleman says. Electronic tattoos placed over the throat could also pick up signals that would help smartphones with speech recognition, he added.
Invasive brain implants remain better at reading brain activity, Coleman notes.
But neuroscientist Miguel Nicolelis at Duke University Medical Center says there is a need for noninvasive technologies such as these for the brain. “People will want to navigate environments just by thinking, or play games just by thinking,” says Nicolelis, who did not take part in this research.
Coleman detailed his group’s most recent findings in Boston on Feb. 17 at the annual meeting of the American Association for the Advancement of Science.