In a groundbreaking experiment, a team from the University of Washington has linked two human brains for a question and answer session – a game that they call “20 Questions with the Mind.” The report has been published in PLOS ONE.
An interactive game has been played using brain-to-brain signals.
The team created a direct brain-to-brain interface (BBI) connection to enable pairs of participants to play the question-and-answer game by transmitting signals from one brain to the other over the Internet.
The lead author was Andrea Stocco, PhD, an assistant professor of psychology and a researcher at University of Washington’s (UW) Institute for Learning and Brain Sciences. One of the co-authors is Prof. Rajesh Rao, from Computer Science and Engineering at UW, specializing brain computer interfaces (BCI). The team has been collaborating since 2011.
Stocco believes that this is the most complex brain-to-brain experiment achieved so far in humans, and the first experiment showing that two brains can be linked to allow one person to guess what the other is thinking.
Thoughts transmitted through visual signals
The activity works by enabling conscious experiences to be communicated through visual signals.
To play the game, two participants sit in darkened rooms nearly a mile apart. Each sees a screen. The “respondent” wears a cap connected to an electroencephalography (EEG) machine that records electrical brain activity. The “inquirer” has a magnetic coil positioned behind the head.
The respondent is shown an object on a computer screen, while the inquirer sees a list of possible objects and associated questions.
The inquirer clicks a mouse, which sends a question to the respondent. The respondent answers “yes” or “no” by focusing his or her mind on one of two flashing LED lights attached to the monitor. The lights flash at different frequencies.
A “no” or “yes” answer both send a signal to the inquirer via the Internet. The signal activates the magnetic coil worn by the inquirer.
The video below shows the question-and-answer game in action:
Answers transmitted through brain signals
A “yes” answer generates a response intense enough to stimulate the visual cortex and cause the inquirer to see a flash of light known as a “phosphene.” The phosphene, appearing as a blob, waves or a thin line, is created when the visual field is brief disrupted; it tells the inquirer that the answer is “yes.” Through answers to the simple yes or no questions, the inquirer identifies the correct item.
Five pairs of participants played 20 rounds of the question-and-answer game. Each game had eight objects and three questions that would solve the game if answered correctly. The sessions were a random mixture of 10 real games and 10 control games that were structured the same way.
To prevent participants from cheating by using sound rather than direct brain communication, inquirers wore earplugs to avoid hearing the different sounds produced by the varying stimulation intensities of the “yes” and “no” responses. The stimulation intensities were also varied slightly from game to game.
In the control games, a plastic spacer was inserted into the device worn by the inquirer, which weakened the magnetic field and prevented the generation of phosphenes. Inquirers knew neither about the spacer, nor which was a real game and which was a control.
Participants successfully guessed the correct object in 72% of the real games but only 18% in the control rounds.
Incorrect guesses in the real games could be caused by several factors, including uncertainty about whether a phosphene had appeared, respondents not knowing the answers to questions, or focusing on both answers, given that the brain does not think about just one thing at any time. Interruptions could also have resulted from hardware problems.
In addition, interpreting something that one sees with the brain is not something that people are accustomed to; this could have been a distraction.
Apart from being the first time that BBI has enabled participants to solve an interactive task using two-way communication in real time, this is also the first experiment to use of stimulation of the visual cortex to convey visual stimuli that are privately experienced and consciously perceived by the inquirer.
While other scientists have achieved brain-to-brain connection between rats and monkeys, the UW team was also the first to demonstrate a direct brain-to-brain connection between humans in 2013, when they used noninvasive technology to send a person’s brain signals over the Internet to control the hand motions of another person.
Future applications: helping those with brain damage or disorders
Co-author Chantel Prat says the next step could be “brain tutoring,” where signals are transferred directly from healthy brains to brains that are developmentally impaired or impacted by external factors such as a stroke or accident, or simply to transfer knowledge from teacher to pupil.
Another possibility is to transmit brain states: signals could be sent from an alert person to a sleepy one, or from a focused student to one with attention-deficit hyperactivity disorder (ADHD).
“Imagine having someone with ADHD and a neurotypical student. When the non-ADHD student is paying attention, the ADHD student’s brain gets put into a state of greater attention automatically.”
Medical News Today recently reported on a man who used a brain computer interface to walk again after 5 years of paralysis.
Written by Yvette Brazier
Copyright: Medical News Today
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