The brain-to-brain transmission of information between humans was carried out without performing any invasive surgery on the test subjects, researchers said.
"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, from the Beth Israel Deaconess Medical Center (BIDMC) 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'" Pascual-Leone said in the study published in the journal PLOS ONE.
Pascual-Leone, together with Giulio Ruffini and Carles Grau leading a team of researchers from Starlab Barcelona, Spain, and Michel Berg, leading a team from Axilum Robotics, Strasbourg, France, successfully transmitted the words "hola" and "ciao" in a computer-mediated brain-to-brain transmission from a location in India to a location in France.
They used internet-linked electroencephalogram (EEG) and robot-assisted and image-guided transcranial magnetic stimulation (TMS) technologies.
Previous studies on EEG-based brain-computer interaction (BCI) have typically made use of communication between a human brain and computer.
But, in the new study, the research team added a second human brain on the other end of the system. Four healthy participants, aged 28 to 50, participated in the study.
One of the four subjects was assigned to the brain-computer interface (BCI) branch and was the sender of the words; the other three were assigned to the computer-brain interface (CBI) branch of the experiments and received the messages and had to understand them.
Using EEG, the research team first translated the greetings "hola" and "ciao" into binary code and then emailed the results from India to France.
There a computer-brain interface transmitted the message to the receiver's brain through noninvasive brain stimulation. The subjects experienced this as phosphenes, flashes of light in their peripheral vision.
The light appeared in numerical sequences that enabled the receiver to decode the information in the message, and while the subjects did not report feeling anything, they did correctly receive the greetings.
A second similar experiment was conducted between individuals in Spain and France, with the end result a total error rate of just 15 per cent, 11 per cent on the decoding end and five per cent on the initial coding side.