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Sender: Robert Karl Stonjek 
Receiver: Psychiatry-Research,Cognitive NeuroScience,Mind and Brain 
Time: 2013-03-01, 00:21:49
Subject: [Mind and Brain] News: Brain-to-brain interface allows transmission 
oftactile and motor information between rats


  


Brain-to-brain interface allows transmission of tactile and motor information 
between rats
February 28th, 2013 in Neuroscience 
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Researchers have electronically linked the brains of pairs of rats for the 
first time, enabling them to communicate directly to solve simple behavioral 
puzzles. Credit: Duke University Medical Center
Researchers have electronically linked the brains of pairs of rats for the 
first time, enabling them to communicate directly to solve simple behavioral 
puzzles. A further test of this work successfully linked the brains of two 
animals thousands of miles apart?ne in Durham, N.C., and one in Natal, Brazil.
The results of these projects suggest the future potential for linking multiple 
brains to form what the research team is calling an "organic computer," which 
could allow sharing of motor and sensory information among groups of animals. 
The study was published Feb. 28, 2013, in the journal Scientific Reports.
"Our previous studies with brain-machine interfaces had convinced us that the 
rat brain was much more plastic than we had previously thought," said Miguel 
Nicolelis, M.D., PhD, lead author of the publication and professor of 
neurobiology at Duke University School of Medicine. "In those experiments, the 
rat brain was able to adapt easily to accept input from devices outside the 
body and even learn how to process invisible infrared light generated by an 
artificial sensor. So, the question we asked was, 'if the brain could 
assimilate signals from artificial sensors, could it also assimilate 
information input from sensors from a different body?'"
To test this hypothesis, the researchers first trained pairs of rats to solve a 
simple problem: to press the correct lever when an indicator light above the 
lever switched on, which rewarded the rats with a sip of water. They next 
connected the two animals' brains via arrays of microelectrodes inserted into 
the area of the cortex that processes motor information.
One of the two rodents was designated as the "encoder" animal. This animal 
received a visual cue that showed it which lever to press in exchange for a 
water reward. Once this "encoder" rat pressed the right lever, a sample of its 
brain activity that coded its behavioral decision was translated into a pattern 
of electrical stimulation that was delivered directly into the brain of the 
second rat, known as the "decoder" animal.
The decoder rat had the same types of levers in its chamber, but it did not 
receive any visual cue indicating which lever it should press to obtain a 
reward. Therefore, to press the correct lever and receive the reward it craved, 
the decoder rat would have to rely on the cue transmitted from the encoder via 
the brain-to-brain interface.
The researchers then conducted trials to determine how well the decoder animal 
could decipher the brain input from the encoder rat to choose the correct 
lever. The decoder rat ultimately achieved a maximum success rate of about 70 
percent, only slightly below the possible maximum success rate of 78 percent 
that the researchers had theorized was achievable based on success rates of 
sending signals directly to the decoder rat's brain.
Importantly, the communication provided by this brain-to-brain interface was 
two-way. For instance, the encoder rat did not receive a full reward if the 
decoder rat made a wrong choice. The result of this peculiar contingency, said 
Nicolelis, led to the establishment of a "behavioral collaboration" between the 
pair of rats.
"We saw that when the decoder rat committed an error, the encoder basically 
changed both its brain function and behavior to make it easier for its partner 
to get it right," Nicolelis said. "The encoder improved the signal-to-noise 
ratio of its brain activity that represented the decision, so the signal became 
cleaner and easier to detect. And it made a quicker, cleaner decision to choose 
the correct lever to press. Invariably, when the encoder made those 
adaptations, the decoder got the right decision more often, so they both got a 
better reward."
In a second set of experiments, the researchers trained pairs of rats to 
distinguish between a narrow or wide opening using their whiskers. If the 
opening was narrow, they were taught to nose-poke a water port on the left side 
of the chamber to receive a reward; for a wide opening, they had to poke a port 
on the right side.
The researchers then divided the rats into encoders and decoders. The decoders 
were trained to associate stimulation pulses with the left reward poke as the 
correct choice, and an absence of pulses with the right reward poke as correct. 
During trials in which the encoder detected the opening width and transmitted 
the choice to the decoder, the decoder had a success rate of about 65 percent, 
significantly above chance.
To test the transmission limits of the brain-to-brain communication, the 
researchers placed an encoder rat in Brazil, at the Edmond and Lily Safra 
International Institute of Neuroscience of Natal (ELS-IINN), and transmitted 
its brain signals over the Internet to a decoder rat in Durham, N.C. They found 
that the two rats could still work together on the tactile discrimination task.
"So, even though the animals were on different continents, with the resulting 
noisy transmission and signal delays, they could still communicate," said 
Miguel Pais-Vieira, PhD, a postdoctoral fellow and first author of the study. 
"This tells us that it could be possible to create a workable, network of 
animal brains distributed in many different locations."
Nicolelis added, "These experiments demonstrated the ability to establish a 
sophisticated, direct communication linkage between rat brains, and that the 
decoder brain is working as a pattern-recognition device. So basically, we are 
creating an organic computer that solves a puzzle."
"But in this case, we are not inputting instructions, but rather only a signal 
that represents a decision made by the encoder, which is transmitted to the 
decoder's brain which has to figure out how to solve the puzzle. So, we are 
creating a single central nervous system made up of two rat brains," said 
Nicolelis. He pointed out that, in theory, such a system is not limited to a 
pair of brains, but instead could include a network of brains, or "brain-net." 
Researchers at Duke and at the ELS-IINN are now working on experiments to link 
multiple animals cooperatively to solve more complex behavioral tasks.
"We cannot predict what kinds of emergent properties would appear when animals 
begin interacting as part of a brain-net. In theory, you could imagine that a 
combination of brains could provide solutions that individual brains cannot 
achieve by themselves," continued Nicolelis. Such a connection might even mean 
that one animal would incorporate another's sense of "self," he said.
"In fact, our studies of the sensory cortex of the decoder rats in these 
experiments showed that the decoder's brain began to represent in its tactile 
cortex not only its own whiskers, but the encoder rat's whiskers, too. We 
detected cortical neurons that responded to both sets of whiskers, which means 
that the rat created a second representation of a second body on top of its 
own." Basic studies of such adaptations could lead to a new field that 
Nicolelis calls the "neurophysiology of social interaction."
Such complex experiments will be enabled by the laboratory's ability to record 
brain signals from almost 2,000 brain cells at once. The researchers hope to 
record the electrical activity produced simultaneously by 10-30,000 cortical 
neurons in the next five years.
Such massive brain recordings will enable more precise control of motor 
neuroprostheses?uch as those being developed by the Walk Again Project?o 
restore motor control to paralyzed people, Nicolelis said.
The Walk Again Project recently received a $20 million grant from FINEP, a 
Brazilian research funding agency, to allow the development of the first 
brain-controlled whole-body exoskeleton aimed at restoring mobility in severely 
paralyzed patients. A first demonstration of this technology is scheduled for 
the opening game of the 2014 Soccer World Cup in Brazil.
Provided by Duke University Medical Center
"Brain-to-brain interface allows transmission of tactile and motor information 
between rats." February 28th, 2013. 
http://medicalxpress.com/news/2013-02-brain-to-brain-interface-transmission-tactile-motor.html
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Robert Karl Stonjek
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