It sounds like sci-fi: monkeys telepathically coordinating to control computers and using their brains to command robots thousands of miles away.
Instead, such experiments are the reality of modern neural engineering according to Dr Peter Ledochowitsch, scientist 1 at the Allen Institute for Brain Science and chief science officer at Cortera Neurotechnologies, Inc.
Ledochowitsch took the audience at the Robotics Innovation Show in London on a journey through recent advances in brain-brain and brain-machine communication.
Telepathy is a relatively new discovery for the field, most recently being demonstrated in a trio of monkeys whose brains were linked via electrodes inserted through their skulls.
The experiment, at the laboratory of Dr Miguel Nicolelis at Duke University Medical Center, saw each of the monkeys take responsibility for moving a cursor along an axis in 3D space.
"They don't know about one another but essentially their brain incorporates the existence of these other entities into its representation of the world and they learn to work together to achieve that particular goal."
What has enabled this limited brain-to-brain communication is the realisation that computers don't have to understand the electrical pulse transmitted inside the brain in order for those signals to do useful work.
"The big insight here was to realise the brain is much better at pattern matching than our machine learning algorithms," he said.
As long as researchers can capture a high enough fidelity representation of the electrical signals inside the brain, they can rely on the brain of the test subject to use visual, auditory and other feedback to learn how to alter its activity to achieve a given goal - be that picking up a cup with a robotic arm or moving a computer cursor to a point on a screen. The process isn't instantaneous, rather the brain will adapt its neural pathways over time.
"The brain rewires and it's essentially exactly the same process as healing after any kind of injury. If you break your jaw, in the beginning you cannot speak clearly but you'll learn to speak clearly again with your newly regrown jaw because your brain hears how you speak and will compensate and close the loop."
The brain's adaptability has also been shown to be useful in controlling machines. The same Nicolelis-led lab sent brain signals from a monkey on a treadmill at Duke University over the internet to control a bipedal robot in Kyoto, Japan.
"These brain signals are being digitised and sent to control a robot. The monkey watches the robot on the screen and that robot can walk. The monkey's brain integrates that robot as essentially an extension of the monkey itself."
Humans are slowly reaping the benefits of some of this research into brain-machine communication. Darpa recently showed off a robotic arm controlled by the wearer's motor and sensory cortex and in last year's Fifa World Cup a man paralysed from the waist down was able to kick a ball, using signals from his brain, captured by electrodes inside a cap, to control a robotic exoskeleton.
However, as might be expected, the experiments that can be carried out on people tend to be far more conservative.
"At this point one should say 'Ok, we're making so much progress, maybe now we should apply that to people and make some people walk that can't'."
Ledochowitsch explained there are limits on what can be achieved by placing electrodes on the scalp, as is done in equipment such as an electroencephalogram (EEG).
"If you want to enable somebody to control complex robots you really can't get all of that information through a low-bandwidth interface like an EEG," said Ledochowitsch.
"However, there is a really big barrier to drilling holes in the human skull and putting electrodes in, for very good reason. It's a loosely kept secret among neuroscientists that once you expose a brain to air it will never be quite the same. It starts a bunch of processes, inflammation, all sorts of things."
Restoring quality of life
In spite of the challenges applying this technology to people, part of what drives Ledochowitsch is the plight of people like South African web developer Martin Pistorius. As a child, an inflammation in Pistorius' brain left him in a state where he was unable to move or communicate, even though he could understand everything going on around him.
"In his words, 'I lived in fear and to put it bluntly, waiting for death to finally release me. I don't know if it's truly possible to express in words what it's like not to be able to communicate, your personality appears to vanish into heavy fog and all your emotions and desires are restricted, stifled and mute within you'," said Ledochowitsch.
"It was the encounter with people like Martin that moved us to start Cortera. The idea was to give severely paralysed people a shred of quality of life back."
His other motivation for getting involved in the field is the desire to probe the mysteries of human consciousness - some of which he believes may be revealed in the coming decades.
Just what might be discovered is already hinted at in theory, such as an hypothesis by neuroscientists Giulio Tononi and Christof Koch that challenges the notion that human consciousness will always be separate.
"One of the interesting predictions that it makes is the reason that you and your neighbour in this room have two separate consciousnesses is because the bandwidth of your communication is so low. You can talk to one another and write but for the most part you're thinking inside your own head.
"If somehow I increased the bandwidth between your two heads, the communication by which you can talk to each other, above a certain threshold, your consciousness would unify into one."
This truth of this theory is yet to be verified, but Ledochowitsch cites incidental evidence from a pair of conjoined twins in Canada with a "dense connection" between their brains who mix up "I" and "we" and also share a sense of what each other is seeing.
He looks forward to a day when more sophisticated neural interfaces — which resolve the various medical, regulatory and technical issues facing us today — might allow a person to transcend the limits of their own mind.
"If this theory is correct will we be able to unify human consciousness. I don't know [if it's true] but it's something that we might get an answer to in our lifetime, which is pretty exciting."
Nick Heath is chief reporter for TechRepublic. He writes about the technology that IT decision makers need to know about, and the latest happenings in the European tech scene.