“Our basic question was ‘Could we bypass our peripheral sensorial systems (responsible for speech, sight, audition, touch, etc.) and establish direct brain-to-brain communication between subjects (located far away from each other in the experiment)?’” explains Giulio Ruffini, director of Starlab Barcelona.
It turned out the answer was “yes!”
In the neuroscientific equivalent of instant messaging Carles Grau and Giulio Ruffini, leading a team of researchers from Starlab and Neuroelectrics (Barcelona, Spain), and Michel Berg, leading a team from Axilum Robotics (Strasbourg, France), together with Alvaro Pascual-Leone from Harvard 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 using internet-linked EEG (electroencephalography) 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, in which electrodes attached to a person’s scalp record electrical currents in the brain as a person realizes an action-thought, such as consciously thinking about moving the arm or leg. The computer then interprets that signal and translates it to a control output, such as a robot or wheelchair.
But, in this 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.
View of emitter and receiver subjects with non-invasive devices supporting, respectively, the BCI based on EEG changes driven by motor imagery (left) and the CBI based on the reception of phosphenes elicited by a neuronavigated TMS (right) components of the B2B transmission system.
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-to-brain interface transmitted the message to the receiver’s brain through noninvasive brain stimulation. The subjects experienced this as phosphenes or 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 % (11% on the decoding end and 5% on the initial coding side).
“We were able to directly and noninvasively transmit a thought - information -from one person to another, without them having to speak, touch, write, hear or see each other,” says Giulio Ruffini. “This in itself is a remarkable step in the progress of human communication. We believe these experiments represent an important first step in exploring the feasibility of complementing or bypassing traditional language-based or motor-based communication to empower human interaction.”
Critical to the success of the experiments was the use of advanced precise neuro-technologies, including wireless EEG (Neuroelectrics) and robotized TMS (Axilum Robotics).
This work originates from FET Open project HIVE (2008-2012), whose goal was to research stimulation paradigms to design, develop and test a new generation of more powerful and controllable non-invasive brain stimulation technologies with the vision of bidirectional machine-brain and brain-to-brain communication. HIVE developed improved electrical current distribution and multi-scale neuron-current interaction models and carried out stimulation experiments using tDCS, TMS, EEG and fMRI in different scenarios. Based on these, Starlab developed multisite transcranial current stimulation technologies (Starstim) implementing real time EEG monitoring and feedback.