Grau et al/PLOS One

Humans just got a step closer to being able to think a message into someone else's brain on the other side of the world: in a first-of-its-kind study, an international team of researchers has successfully achieved brain-to-brain transmission of information between humans.

The team, comprising researchers from Harvard Medical School teaching affiliate Beth Israel Deaconess Medical Center, Starlab Barcelona in Spain, and Axilum Robotics in Strasbourg, France, used a number of technologies that enabled them to send messages from India to France -- a distance of 5,000 miles (8046.72km) -- without performing invasive surgery on the test subjects.

"We wanted to find out if one could communicate directly between two people by reading out the brain activity from one person and injecting brain activity into the second person, and do so across great physical distances by leveraging existing communication pathways," said co-author Alvaro Pascual-Leone, MD, PhD, director of the Berenson-Allen Center for Noninvasive Brain Stimulation at Beth Israel Deaconess Medical Center and Professor of Neurology at Harvard Medical School.

"One such pathway is, of course, the internet, so our question became, 'Could we develop an experiment that would bypass the talking or typing part of internet and establish direct brain-to-brain communication between subjects located far away from each other in India and France ?'"

Using a combination of internet-connected electroencephalogram and robot-assisted, image-guided transcranial magnetic stimulation (which, as the name suggests, uses electromagnetic induction to stimulate the brain from the outside), the team was able to communicate words from one human to another.

The team used a similar set-up to that commonly used in brain-computer interface studies. A human subject had electrodes attached to their scalp, which recorded electrical currents in the brain as the subject had a specific thought. Usually, this is interpreted by a computer and translated to a control output, such as a robotic arm, or a drone.

In this case, though, the output target was another human.

Grau et al/PLOS One

The study had four participants, aged between 28 and 50. One participant was assigned to the brain-computer interface to transmit the thought, while the other three were assigned to the computer-brain interface to receive the thought.

At the BCI end, the words "Ciao" and "Hola" were translated into binary. This was then shown to the emitter subject, who was instructed to envision actions for each piece of information: moving their hands for a 1 or their feet for a 0. An EEG then captured the electrical information in the sender's brain as they thought of these actions, which resulted in a sort of neural code for the binary symbols -- which in turn was code for the words.

This information was then sent to the three recipient subjects via TMS headsets, stimulating the visual cortex so that the recipient, with ears and eyes covered, saw the binary string as a series of bright lights in their peripheral vision: if the light appeared in one location, it was a 1, and the second location denoted a 0. This information was received successfully and decoded as the transmitted words.

This experiment, the researchers said, represents an important first step in exploring the feasibility of complementing or bypassing traditional means of communication, despite its current limitations -- the bit rates were, for example, quite low at two bits per minute. Potential applications, however, include communicating with stroke patients, for example.

"We anticipate that computers in the not-so-distant future will interact directly with the human brain in a fluent manner, supporting both computer- and brain-to-brain communication routinely," the team concluded. "The widespread use of human brain-to-brain technologically mediated communication will create novel possibilities for human interrelation with broad social implications that will require new ethical and legislative responses."

You can read the full study online in the journal PLOS One.