NEW YORK 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 behavior, researchers reported on Thursday 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. 
 
 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 muskets. 
 
 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-paralyzed 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 SIGNALS 
 
 In 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. 
 
 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' success. 
 
 The encoder rat did not get that reward if a decoder rat goofed. In that case, the encoder rat, apparently realizing 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. 
 
 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, and the paper is at dx.doi.org/10.1038/srep01319 
 
 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. 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 this." 
 
 "It's cool that the stimulus came from another brain" rather than an electrical device, agreed bioengineer Douglas Weber of Pittsburgh. 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 "brain-net." 
 
 "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." 
 
 (Reporting by Sharon Begley; Editing by Jilian Mincer and Claudia Parsons) ||||| It’s not exactly a Vulcan mind meld, but it’s not far off. Scientists have wired the brains of two rats together and shown that signals from one rat’s brain can help the second rat solve a problem it would otherwise have no clue how to solve. 
 
 The rats were in different cages with no way to communicate other than through the electrodes implanted in their brains. The transfer of information from brain to brain even worked with two rats separated by thousands of kilometers, one in a lab in North Carolina and another in a lab in Brazil. 
 
 “We basically created a computational unit out of two brains,” says neuroscientist Miguel Nicolelis of Duke University, who led the study. 
 
 Nicolelis is a leading figure in brain-machine interface research and the man behind a bold plan to develop a brain-controlled exoskeleton that would allow a paralyzed person to walk onto the field and kick a soccer ball at the opening ceremony of next year’s World Cup in Brazil. 
 
 He says the new findings could point the way to future therapies aimed at restoring movement or language after a stroke or other brain injury by using signals from a healthy part of the brian to retrain the injured area. Other researchers say it’s an interesting idea, but it’s a long way off. 
 
 But Nicolelis’s group is known for pushing the envelope. Previously, they have given monkeys an artificial sense of touch they can use to distinguish the “texture” of virtual objects. More recently, they gave rats the ability to detect normally invisible infrared light by wiring an infrared detector to a part of the brain that processes touch. All this work, Nicolelis says, is relevant to developing neural prostheses to restore sensory feedback to people with brain injuries. 
 
 In the new study, the researchers implanted small electrode arrays in two regions of the rats’ brains, one involved in planning movements, and one involved in the sense of touch. 
 
 Then they trained several rats to poke their noses and whiskers through a small opening in the wall of their enclosure to determine its width. The scientists randomly changed the width of the opening to be either narrow or wide for each trial, and the rats had to learn to touch one of two spots depending on its width. They touched a spot to the right of the opening when it was wide and the spot on the left when it was narrow. When they got it correct, they received a drink. Eventually they got it right 95 percent of the time. 
 
 ‘It’s a pretty cool idea that they’re in tune with each other and working together’ 
 
 Next, the team wanted to see if signals from the brain of a rat trained to do this task could help another rat in a different cage choose the correct spot to poke with its nose — even if it had no other information to go on. 
 
 They tested this idea with another group of rats that hadn’t learned the task. In this experiment, one of these new rats sat in an enclosure with two potential spots to receive a reward but without an opening in the wall. On their own, they could only guess which of the two spots would produce a rewarding drink. As expected, they got it right 50 percent of the time. 
 
 Then the researchers recorded signals from one of the trained rats as it did the nose-poke task and used those signals to stimulate the second, untrained rat’s brain in a similar pattern. When it received this stimulation, the second rat’s performance climbed to 60 or 70 percent. That’s not nearly as good as the rats who could actually use their sense of touch to solve the problem, but it’s impressive given that the only information they had about which spot to chose came from another animal’s brain, Nicolelis says. 
 
 Both rats had to make the correct choice, otherwise neither one got a reward. When that happened, the first rat tended to make its decision more quickly on the next trial, and its brain activity seemed to send a clearer signal to the second rat, the team reports today in Scientific Reports. That suggests to Nicolelis that the rats were learning to cooperate. 
 
 The brain-to-brain communication link enables the rats to collaborate in a novel way, he says. ”The animals compute by mutual experience,” he said. ”It’s a computer that evolves, that’s not set by instructions or an algorithm.” 
 
 From an engineering perspective, the work is a remarkable demonstration that animals can use brain-to-brain communication to solve a problem, said Mitra Hartmann, a biomedical engineer who studies rats’ sense of touch at Northwestern University. “This is a first, to my knowledge, although the enabling technology has been around for a while.” 
 
 “From a scientific point of view, the study is noteworthy for the large number of important questions it raises, for example, what allows neurons to be so ‘plastic’ that the animal can learn to interpret the meaning of a particular stimulation pattern,” Hartmann said. 
 
 “It’s a pretty cool idea that they’re in tune with each other and working together,” said neuroscientist Bijan Pesaran of New York University. But Pesaran says he could use some more convincing that this is what’s actually going on. For example, he’d like to see the researchers extend the experiment to see if the rats on the receiving end of the brain-to-brain communication link could improve their performance even more. ”If you could see them learning to do it better and faster, then I’d really be impressed.” 
 
 Pesaran says he’s open to the idea that brain-to-brain communication could one day be used to rehabilitate brain injury patients, but he thinks it might be possible to accomplish the same thing by stimulating the injured brain with computer-generated patterns of activity. ”I don’t get why you’d need another brain to do that,” he said. ||||| In an experiment that sounds straight out of a science fiction movie, a Duke neuroscientist has connected the brains of two rats in such a way that when one moves to press a lever, the other one does, too — most of the time. 
 
 The neuroscientist, Miguel Nicolelis, known for successfully demonstrating brain-machine connections, like the one in which a monkey controlled a robotic arm with its thoughts, said this was the first time one animal’s brain had been linked to another. 
 
 The question, he said, was: “Could we fool the brain? Could we make the brain process signals from another body?” The answer, he said, was yes. 
 
 He and other scientists at Duke, and in Brazil, published the results of the experiment in the journal Scientific Reports. The work received mixed reviews from other scientists, ranging from “amazing” to “very simplistic.” 
 
 Much of Dr. Nicolelis’s work is directed toward creating a full exoskeleton that a paralyzed person could operate with brain signals. Although this experiment is not directly related, he said, it helps refine the ability to read and translate brain signals, an important part of all prosthetic devices connected to the brain, and an area in which brain science is making great advances. 
 
 He also speculated about the future possibility of a biological computer, in which numerous brains are connected, and views this as a small step in that direction. 
 
 The experiment involved extensive training for both rats, with water as a reward. One, the so-called encoder rat, learned to press one of two levers, left or right, in response to a light signal over the correct lever. 
 
 The second, or decoder rat, also learned to press either the left or right lever in response to light, but then went on to respond instead to brain stimulation from his rat partner. 
 
 For the experiment, recording electrodes were implanted in the primary motor cortex of the encoder rat and stimulating electrodes in the same area in the decoder rat. 
 
 Then, as the encoder responded to the light appearing over one lever or the other, its pattern of brain activity was sent to a computer, which simplified the pattern for transmission to the decoder rat. The signal received by the decoder was not the same as the stimulation it had previously received in training, Dr. Nicolelis said. 
 
 Seven out of 10 times, the decoder rat pressed the right lever. 
 
 The researchers reported similar results in other experiments, based on whether the rats sensed a narrow or wide opening with their whiskers. In this case the electrodes were implanted in a different part of the brain, where sensory signals are received. 
 
 Ron D. Frostig, a neuroscientist at the University of California, Irvine, said, “I think it’s an amazing paper.” He described it as a “beautiful proof of principle” that information could be transferred from one brain to another in real time — not by mind-reading or telepathy, but a transfer of what might be called the impulse to act. 
 
 Andrew B. Schwartz, a neuroscientist at the University of Pittsburgh, was less impressed. He described the work as “very simplistic” and pointed out that the rat receiving the signal pushed the right lever only 7 out of 10 times and would have done so 5 out of 10 times by chance. 
 
 There was an additional twist to the research. Dr. Nicolelis added a touch of international drama by locating one rat at Duke, in North Carolina, and another in Natal, Brazil. Similarly, in his earlier work, he had a monkey in North Carolina operate a robotic arm in Japan. 
 
 The distance does not change the essential science, but adds some difficulty to the experiment, because the signals sent from one brain to the other had to go through an Internet connection.
– It is, in the words of Wired, a "rodent mind meld." A Duke neuroscientist planted electrodes in the brains of two rats and discovered that signals from one could control the actions of the other, reports the New York Times. In one experiment, the rats were trained to press a specific lever upon seeing a red light in order to get a drink of water as reward. The first rat saw the light and pressed the correct lever. The second rat wasn't shown the light but pressed the correct lever anyway, most of the time, after receiving the signals from the first rat's brain. What's more, the rats got their reward only if both rodents responded correctly. Researchers say the first rat apparently figured this out and started sending clearer signals to his pal, which boosted the success rate even more. Ultimately, Duke's Miguel Nicolelis hopes his work leads to an exoskeleton that can be controlled by a paralyzed person. On this particular experiment, however, Reuters quotes an anonymous neuroscientist a little leery about the precedent, fearful of a slippery slope worthy of a sci-fi blockbuster. He sees the possibility of "battalions of animal soldiers—or even human soldiers—whose brains are remotely controlled by others."