A new study has successfully allowed rats to communicate with one other via an electronic linkage, the first such experiment conducted.
The research, published in the journal Scientific Reports, was led by Miguel Nicolelis of Duke University. The study expanded on work the research team had previously completed about brain-machine interfaces. Through special brain implants, researchers at the Duke University Medical Center in North Carolina were able to allow the lab rats to communicate with each other through wires coming out of their heads.
The brain interface allowed sensory and motor information to be passed between the two rats, according to researchers. The brain implants, the first of their kind, is the first successful brain interface ever created. In order to test the viability of their instrument, the research team tested if the rat receiving the information could interpret it. They even tested their invention on rats thousands of miles apart.
Working off of previous research, Nicolelis and his team created a brain-machine interface that allowed rats to “touch” infrared light. The team of scientists hooked electrodes to the part of the rat’s brain that processed tactile information and attached them to infrared senors.
Now in their most recent study, the team attempted to discover if it was possible to create a communication channel between two rats using a brain-machine interface.
“Until recently we used to record this brain activity and send it to a computer…and the [computer] tells us what the animal is going to do,” Nicolelis said in an interview with BBC’s Science in Action. “So we reasoned, if we can do that with a computer, could another brain do that?”
In order find out if their interface worked, scientists first trained the rats to press certain levers when a light switched on The rats would then receive a sip of water as a reward. They then attached the animals’ brains through an interface made of micro-electrodes that were about one hundredth of the diameter of human hair. The electrodes were attached to the are of the brain that processes motor signals.
One rat, named the “encoder,” pressed the correct lever when signaled through the light. This rat’s brain impulses then traveled through the electrodes and stimulated the brain of the second rat named the “decoder.” The decoder received no light signaling which lever to push, but instead relied on the brain signals of the encoder rate. In the end, the decoder rat obtained a maximum success rate of 70 percent.
According to Nicolelis, the decoder rat rarely understood the signals right away, an indication that information was passed between the two rats.
“[It] takes about 45 days of training an hour a day,” he said. “There is a moment in time when…it clicks. Suddenly the [decoder] animals realizes: ‘Oops! The solution is in my head. It’s coming to me’ and he gets it right.”
The team also enforced a feedback system where the encoder rat could not receive extra water if the decoder did not pick the right lever. Nicolelis said this caused the encoder’s signals to become cleared, which gave the decoder a better chance of figuring it out. He said, “basically [the second rat] us working as…a biological computer.”