Brain to brain network
© MARK STONE/UNIVERSITY OF WASHINGTON
A receiver (centre) and two senders ready to work their brains. Come game time, they were in separate rooms.
US computer engineers have reported creating a way for two people to help a third person solve a problem using only their minds.

It's called BrainNet and, the team from the University of Washington says, it is the first demonstration of two things: a brain-to-brain network of more than two people, and a person being able to both receive and send information to others using only their brain.

They acknowledge it's a baby step on the road to telepathic communication, but it's a step, nonetheless.

"Our equipment is still expensive and very bulky, and the task is a game," says corresponding author Rajesh Rao. "We're in the 'Kitty Hawk' days of brain interface technologies. We're just getting off the ground."

The game in question is much like the old-school computer favourite Tetris, involving manoeuvring blocks of varying shapes into position to follow a specific line as they fall from the top of the screen.

In the version Rao and colleagues devised, three people played the one game, while sitting in separate rooms. Two, called "senders", could see the blocks and the lines but couldn't control the game. The third, the "receiver", could see the blocks but not the lines, but could tell the game to rotate a block when necessary to complete a line.

All wore electroencephalography caps that picked up electrical activity in their brains.

The senders made recommendations about whether to rotate a block by concentrating on one of two LED lights - one for yes and the other no.

These lights flashed a different number of times per second, and these two patterns triggered unique types of activity in the brain, which the caps could pick up and send to the receiver.

"To deliver the message to the receiver, we used a cable that ends with a wand that looks like a tiny racket behind the receiver's head," says co-author Andrea Stocco. "This coil stimulates the part of the brain that translates signals from the eyes.

"We essentially trick the neurons in the back of the brain to spread around the message that they have received signals from the eyes. Then participants have the sensation that bright arcs or objects suddenly appear in front of their eyes."

The receiver would see a bright flash if the advice was to rotate the block, but no flash if the answer was no. After assessing advice from both senders, the receiver would make a decision (which the senders got to review) then finally act upon it via the cap.

Results were impressive. On average, each group successfully cleared the line 81% of the time, or for 13 out of 16 trials.

The researchers also wanted to know if a receiver would learn over time to trust one sender over the other based on their reliability. They purposely picked one of the senders to be a "bad sender" and found that the receiver did indeed begin to favour the good guy.

Not surprisingly, the researchers say they hope their results pave the way for future work on brain-to-brain interfaces.

However, they also suggest its is an appropriate time to start having a broader conversation about the ethics of this kind of brain augmentation research and develop protocols to ensure that people's privacy is respected as the technology improves.

The research is published in a paper in the journal Scientific Reports.