The experiment is proof of principle that one brain can transmit information to another without visual or tactile cues.
It's not quite telepathy, but it's the closest anyone has ever come to getting a mammal to read another mammal's mind. A research team led by neurobiologist Miguel Nicolelis of Duke University has wired together the brains of two rats, allowing them transmit information between each other and cooperate. The results could help improve the design of neural-controlled prosthetic devices. And perhaps more than that, they also show that one day we could network brains as well as computers, or communicate by translating neural activity in the brain into electronic signals.
In the experiment, the Duke scientists first trained two rats to press one of two levers when a particular light switched on. Next, they then connected the animals' brains with tiny electrodes, each a fraction the size of a human hair. The electrodes linked the parts of the rats' brains that process motor signals. Rat number one was called the "encoder" and rat number two was the "decoder." The first rat's job was to receive the visual cue to press the lever. If it got it right, it got a reward.
As the encoder rat did its task, the electrical activity in the encoder rat's brain was then translated into a signal and transmitted to the decoder rat. That rat would then press its own lever. For the second rat, though, there was no light cue to tell it which corresponding lever was correct. It could only go by the signal it received from the other rat. It hit the correct lever an average of about 64 percent of the time, and sometimes up to 72 percent -- much better than if it were only doing it by chance.
To confirm that this was an effect of the signals from the encoder rat's brain, Nicolelis and his team gave the decoder rat the same stimulation, but this time from a computer. They got a similar result.
Another experiment tested whether the rat's brain could transmit information about touch. This time the rats were trained to put their nose through an opening and, using their whiskers, distinguish whether the opening was wide or narrow. For wide openings, the rats were taught to poke a computer port on their right. For narrow openings, they poked to the left.
Once trained, the rats were wired up to each other. When the encoder rat poked the relevant port, the scientists recorded the brain activity and sent the signal to the decoder rat. The decoder chose the correct side – left or right – to poke 60 to 65 percent of the time.