Direct brain-to-brain connection established between humans

Scientists, led by an Indian-origin researcher, have successfully linked the brains of two people, allowing one person to control the hands of another using just their thoughts.

Researchers from the University of Washington replicated a direct brain-to-brain connection between pairs of people as part of a scientific study following the team's initial demonstration a year ago.

In the new study, which involved six people, researchers were able to transmit the signals from one person's brain over the Internet and use these signals to control the hand motions of another person within a split second of sending that signal.

"The new study brings our brain-to-brain interfacing paradigm from an initial demonstration to something that is closer to a deliverable technology," said co-author Andrea Stocco, a research assistant professor of psychology.

"Now we have replicated our methods and know that they can work reliably with walk-in participants," said Stocco.

The research team led by Rajesh Rao, a UW associate professor of computer science and engineering, combined two kinds of noninvasive instruments and fine-tuned software to connect two human brains in real time.

The process is fairly straightforward. One participant is hooked to an electroencephalography machine that reads brain activity and sends electrical pulses via the Web to the second participant, who is wearing a swim cap with a transcranial magnetic stimulation coil placed near the part of the brain that controls hand movements.

Using this setup, one person can send a command to move the hand of the other by simply thinking about that hand movement.

The study involved three pairs of participants. Each pair included a sender and a receiver with different roles and constraints.

They sat in separate buildings on campus about a half mile apart and were unable to interact with each other in any way - except for the link between their brains.

Each sender was in front of a computer game in which he or she had to defend a city by firing a cannon and intercepting rockets launched by a pirate ship.

But because the senders could not physically interact with the game, the only way they could defend the city was by thinking about moving their hand to fire the cannon.

Across campus, each receiver sat wearing headphones in a dark room - with no ability to see the computer game - with the right hand positioned over the only touch-pad that could actually fire the cannon.

If the brain-to-brain interface was successful, the receiver's hand would twitch, pressing the touch-pad and firing the cannon that was displayed on the sender's computer screen across campus.

Researchers found that accuracy varied among the pairs, ranging from 25 to 83 per cent. Misses mostly were due to a sender failing to accurately execute the thought to send the "fire" command.