Rats 'can network at long distance'
It sounds like a case for the X-Files, but scientists have demonstrated a form of mind control by linking two brains thousands of miles apart.
The brains in question belonged to a pair of rats, one in the US city of Durham, North Carolina, the other in Natal, Brazil. By recording brain signals from one rat and transmitting them over the internet to the other, scientists were able to alter the second rodent's behaviour.
"Even though the animals were on different continents, with the resulting noisy transmission and signal delays, they could still communicate," said Dr Miguel Pais-Vieira, from Duke University, Durham. "This tells us that we could create a workable, network of animal brains distributed in many different locations."
In the first of a set of experiments published in the Nature journal Scientific Reports, researchers taught an "encoder" rat to respond to a light by pressing a particular lever. Brain recordings encoding its behaviour were sent to a "decoder" animal via electrodes into its brain.
The decoder rat had no light signal, but when stimulated still pressed the right lever to receive a reward 70% of the time - far more often than it would have by chance.
A two-way link between the animals was established by ensuring the encoder rat did not receive a full reward if the decoder made a wrong choice. As a result, the encoder became more decisive and generated clearer brain signals.
"We saw that when the decoder rat committed an error, the encoder basically changed both its brain function and behaviour to make it easier for its partner to get it right," said Dr Miguel Nicolelis, also from Duke University.
A second test involved pairs of rats distinguishing between narrow and wide openings using their whiskers. Again, signals transmitted from one rat helped the other make the right action to obtain a reward. This experiment was successfully repeated with communicating rats in the US and Brazil.
The whisker study had an even odder outcome. Evidence suggested that the decoder rat began to develop a double identity by picking up sensations from two sets of whiskers - its own and those of its partner.
"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," said Dr Nicolelis. "We detected cortical neurons that responded to both sets of whiskers."