BehindTheMedspeak: The Rat With Two Brains

How great is it that a scientist has succeeded in joining the brains of two rats, such that when one thinks something the other does it?

You know it's only a matter of time till it comes to humanville.

Steve Martin's 1983 classic "The Man With Two Brains" wasn't all that far ahead of its time after all: 30 years is what, a blink of an eye on a Big Bang-oriented scale.

But I digress.

Below, excerpts from James Gorman's New York Times story about this fantastic experiment.

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.

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.

Below, the abstract of Nicolelis's paper, published February 28, 2013 in Scientific Reports (the paper in its entirety — figures, tables, references, and associated materials — is available at the same site).

A Brain-to-Brain Interface for Real-Time Sharing of Sensorimotor Information

A brain-to-brain interface (BTBI) enabled a real-time transfer of behaviorally meaningful sensorimotor information between the brains of two rats. In this BTBI, an "encoder" rat performed sensorimotor tasks that required it to select from two choices of tactile or visual stimuli. While the encoder rat performed the task, samples of its cortical activity were transmitted to matching cortical areas of a "decoder" rat using intracortical microstimulation (ICMS). The decoder rat learned to make similar behavioral selections, guided solely by the information provided by the encoder rat's brain. These results demonstrated that a complex system was formed by coupling the animals' brains, suggesting that BTBIs can enable dyads or networks of animal's brains to exchange, process, and store information and, hence, serve as the basis for studies of novel types of social interaction and for biological computing devices.

Below, excerpts from Sharon Begley's Reuters article.

"Mind melds" move from science fiction to science in rats

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.

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.

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 here.

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.

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."

Speaking as a scientist who has been gobsmacked repeatedly by the fantastic work of others in my field, I can tell you with absolute certainty — 100% — that Northwestern University neuroscientist Lee Miller's description of the goals of Nicolelis's group as "a fantasy" is nothing other than pure jealousy: color Miller green with raw envy and angst.

Heh.

[via reader dc3]