The scientists call it a "brain link," and it is
the closest anyone has gotten to a real-life "mind meld": the
thoughts of a rat romping around a lab in Brazil were captured by electronic
sensors and sent via Internet to the brain of a rat in the United States.
The result: the second rat received the thoughts of the
first, mimicking its behaviour, researchers reported in Scientific Reports, a journal of the Nature Publishing Group.
Adding to its
science-fiction feel, the advance in direct brain-to-brain communication could
lay the foundation for what Duke University Medical Center neurobiologist
Miguel Nicolelis, who led the research, calls an "organic computer"
in which multiple brains are linked to solve problems solo brains can't.
How the study was
If that sounds like an ethical minefield, several experts
think so too, especially since Nicolelis is now working on brain-to-brain
communication between monkeys."Having non-human primates communicate
brain-to-brain raises all sorts of ethical concerns," said one
neuroscientist, who studies how brains handle motor and sensory information,
but who asked not to be named.
"Reading about putting things in animals' brains and
changing what they do, people rightly get nervous," envisioning battalions
of animal soldiers - or even human soldiers - whose brains are remotely
controlled by others. That could make drone warfare seem as advanced as
Pentagon’s Defense Advanced Research Projects Agency
Nicolelis's lab received $26 million from the Pentagon's
Defense Advanced Research Projects Agency (DARPA) for work on brain-machine
interfaces, as this field is called. The linked rat brains in the study built
on 15 years of research in brain-machine interfaces.
These interfaces take electrical signals generated from the
brains of severely-paralysed people and translate them into commands that move
a mechanical arm, a computer cursor or even the patient's own arm. Such work
led Nicolelis to ask, can one brain decode the electrical signals generated by
another? The answer - at least for rats - was yes.
CODED SIGNALSIn one experiment, the Duke researchers trained
rats destined to be message senders, or encoders, to press a lever when a red
light above them turned on. Doing so earned the animals a sip of water. Rats
intended to be message receivers, or decoders, were trained to press a lever
when the scientists electrically stimulated their brains via implants.
Experts monitored the
rats’ brain activity
The scientists next connected the rats' brains directly,
inserting microelectrodes roughly one-hundredth the width of a human hair. Now
when an encoding rat saw the red light and pressed the lever, its brain
activity sped directly into the brains of seven decoder rats.
The decoders did not see a red light. Nevertheless, they
usually pressed the correct lever and earned their after-work libation. The
encoder rats got the same treat, reaping the rewards of their partners'
The encoder rat did not get that reward if a decoder rat
goofed. In that case, the encoder rat, apparently realising what had happened,
seemed to concentrate harder on its task: it decided more quickly to choose the
correct lever and quashed extraneous thoughts so as not to muddy the signal
with, perhaps, daydreams about escaping the lab or pressing the wrong lever.
Videos of the
experiment available online
As a result, the signal got louder and sharper, and the
decoder rats made fewer mistakes."The encoder basically changed its brain
function to make the signal cleaner and easier for its partner to get it
right," Nicolelis said. Videos of the experiments are available at www.nicolelislab.net.
The researchers also trained pairs of rats to distinguish a
narrow opening from a wide one using their whiskers. The animals learned to
poke a water port on the left side of the chamber with their nose if they
sensed a narrow opening, and a port on the right if they sensed a wide opening.
As with the lever press, when the brain waves that signified
"narrow door" traveled from the encoder rat to the decoder rat, the
latter usually poked the correct port. In these experiments, the rats were in
Nicolelis's lab at Duke and their brains were connected by long, thin wires.
Reach of brain waves
and experiments in study
To show the reach of brain waves, the scientists re-ran the
experiments with encoder rats in Natal, Brazil, and decoder rats at Duke.
The brain signals traveled over the Internet. But even with
the resulting noise, the mind melds usually succeeded. 'COMPLETE FANTASY'Some
other researchers were not impressed. For one thing, the Internet aspect is not
novel: in a previous study, electrical activity in the brain of a monkey at
Duke was sent via the Internet and controlled a robot arm in Japan.
Neurobiologist Andrew Schwartz of the University of
Pittsburgh, a leader in the field of brain-computer interactions, said that
"from a scientific/engineering point of view, this is of limited
interest." Brain-machine interfaces "have moved far beyond
"It's cool that the stimulus came from another
brain" rather than an electrical device, agreed bioengineer Douglas Weber
Results show animals detect
electrical stimuli delivered to the brain
But "many labs have shown that animals can detect
electrical stimuli delivered to the brain. This paper simply shows that the
animals can detect electrical stimuli... from another rat's brain. There is
nothing unexpected or surprising.
"The Duke team sees the study as a step toward what
lead author Miguel Pais-Vieira calls "a workable network of animal
brains." They are currently trying to link four rats' brains and
(separately) two monkeys' brains, each in what Nicolelis calls a
"Wiring brains together to accomplish something useful
strikes me as a fantasy," said neuroscientist Lee Miller of the Feinberg
School of Medicine at Northwestern University, whose brain-machine research is
intended to help paralyzed patients move.
Asked how likely it is that one day human brains would be
linked, Nicolelis said: "I wouldn't mind if, 100 years from now, people
say two rats started human brain nets."