Science and Technology

Mice brain exchange information almost 10,000 km away

The novelty is the result of using the first interface brain-brain, with transfer of sensory and motor information

Foto: Katie Zhuang/Mguel Nicolelis/Duke University
Team created the so-called 'brain-brain interface
Team created the so-called 'brain-brain interface "that connected directly brains of two mice so that they could communicate

Study led by Brazilian neuroscientist Miguel Nicolelis, a researcher at the Center for Neuroengineering at Duke University (USA), and researchers at the International Institute of Neuroscience (IINN-ELS) Christmas (Brazil), describes the operation of the first brain-brain interface that allows direct transfer, in real time, of sensory and motor information between the brains of rats. The research was published in the journal Scientific Reports on Thursday (28).

Researchers have linked the brains of animals Durham, North Carolina (USA), the other in the Laboratory IINN-ELS, in Natal, Rio Grande do Norte (Brazil).

According to the study, the conquest can allow, in the future, connecting multiple brains to form what the researchers termed the first "organic computer", allowing the sharing of information between motor and sensory groups of animals.

"Our previous studies with brain-machine interfaces have convinced us that the brain is much more plastic than we thought," said Nicolelis. In those experiments, the brain was able to easily adapt to accept stimuli from devices outside the body and even learn to process infrared light generated by an artificial sensor. So the question that guided this study was: since the brain can assimilate signs of artificial sensors, which could be also assimilate information generated by sensors coming from a different body? ".

<b> Trained rats </ b>

To test this hypothesis in a series of experiments, the researchers first trained rats pairs to solve a simple problem: press the lever correct sparked when an indicator light above the lever to get a drink of water. After they connected brains of both animals through two arrays of microelectrodes inserted into the area of ​​cortex that processes information motor.

An animal of double the animal was designated as "encoder". This animal received a visual signal that the informed press that lever to get a reward net. Since this mouse "encoder" pressed the correct lever, a sample of brain activity that encoded the behavioral decision it was translated into a pattern of electrical stimulation, which was sent directly to the brain of the second animal of the duo, known as the animal " Decoder ". The mouse decoder had the same types of levers in your camera, but has received no visual signal indicating which lever he should press for a reward. Therefore, to press the correct lever and receive the reward he wanted, the mouse decoder depended on the signal transmitted by the encoder via the brain-brain interface.

The researchers then conducted tests to determine how well the animal decoder could decode the brain signal encoder mouse to choose the correct lever. On average, the rat decoder obtained a success rate of about 70 percent, only slightly below the maximum possible rate of success of 78 percent, which researchers were deemed possible. This maximum rate is what the researchers found they could get when they transmitted electrical signals directly to the regular mouse brain decoder, which had not been generated by the encoder.

<b> Collaboration </ b>

Importantly, the communication provided by this brain-brain interface (BTBI) was duplicate. For example, the rat received a reward encoder not complete if the mouse decoder made a wrong choice. The result of this peculiar contingency led to the establishment of a "behavioral collaboration between the pair of rats, said Nicolelis.

"We have seen that when the rat made an error decoder, the encoder basically changed both their brain function and the behavioral so as to make it easier to adjust his partner"

"We saw that when the mouse made a mistake decoder, encoder basically changed both their brain function and the behavioral, in order to make it easier for your partner to hit," said Nicolelis. The mouse encoder improved signal / noise ratio of brain activity that represented the decision, and the signal became cleaner and easier to detect. The mouse encoder also made a decision faster and cleaner when choosing the correct lever to press.

Invariably, when the encoder was making these adjustments, the decoder took the right decision more often, so that both could a better reward. "In a second series of experiments with this BTBI, researchers trained pairs of rats to distinguish between a narrow gap or using their large facial whiskers. If the opening was narrow, the rats had to put his nose on a door on the left side of the chamber to receive a reward. When the opening was wider, they had to put your nose in the door right side. So, the researchers divided the mice into encoders and decoders. decoders were trained to associate pulses of electrical stimulation of the cortex with a tactile reward present on the left side, while the absence of stimulation should be indicated by the animal placement nose right in the door. During attempts in which the encoder detects the width of the opening and the choice conveyed to the brain decoder, the decoder

achieved a success rate of about 65 percent, significantly higher than would be expected by chance alone.

Mice <b> decoders </ b>

After a series of experiments, the researchers demonstrated that pairs of rats, connected on two continents, could still work together in tactile discrimination task, taking advantage of a brain-brain interface.

"So while the animals are on different continents, with transmission delays and resulting noisy signal, they still were able to communicate," said Father Miguel Vieira, postdoctoral student and first author of the study. "This suggests that in the future we can create a network of brains of animals distributed in several different places."

Nicolelis concluded that "these experiments showed that we have established a direct communication link between brains and sophisticated and that the brain works as a decoder device pattern recognition. So basically, we are creating a sort of organic computer. Such a computer solves a puzzle differently-head of a Turing machine ', "he said. A "Turing machine" is the classic computer model used by all commercial computers, in which a computer operates the data using a predetermined set of instructions, also known as an algorithm to arrive at a solution.

"But in this case, we are not introducing instructions but only a signal that represents a decision by mouse encoder, which is transmitted to the brain of the animal decoder, you have to figure out how to solve the puzzle. So we basically created a central nervous system consisting of two brains of rats. " Nicolelis noted that, in theory, such a system is not limited to a couple of animals, but could include a network of brains that he termed "BraiNet."

<b> Network Brain "</ b>

Researchers from Duke and IINN-ELS are now working in various animal experiments to bind cooperatively to solve more complex behavioral tasks. Nicolelis originally introduced the concept of a brain network "in his book Our Very Besides I: The New Neuroscience linking brains and machines and how it can change our lives (Cia das Letras, 2011).

"We can not even predict what type of emergent properties arise when animals begin to interact as part of a BraiNet. Theoretically, you could imagine that the combination of brains could provide solutions to individual brains can not achieve alone." This connection to could mean that an animal would incorporate the sense of "I" of another animal, he said. "In fact, our studies of mice decoders in these experiments showed that the brain decoder began acting in its tactile cortex not only own the plot but also the whiskers mouse encoder. Detected cortical neurons that responded to both sets of whiskers , which means that the mouse has created a second representation of a second body than the original. " Basic studies of such adjustments may lead to a new field that Nicolelis calls "neurophysiology of social interaction."

Brain-to-brain interface transmits brain activity directly from one rat to another

"To understand the social interaction, we could record from the animals' brains while they are socializing and analyze how the brain adapts, for example, when a new member is introduced into the colony, he said.

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