Ian Sample in The Guardian:
The US team fitted two rats with devices called brain-to-brain interfaces that let the animals collaborate on simple tasks to earn rewards, such as a drink of water.
In one radical demonstration of the technology, the scientists used theinternet to link the brains of two rats separated by thousands of miles, with one in the researchers' lab at Duke University in Durham, North Carolina, and the other in Natal, Brazil.
Led by Miguel Nicolelis, a pioneer of devices that allow paralysed people to control computers and robotic arms with their thoughts, the researchers say their latest work may enable multiple brains to be hooked up to share information.
“These experiments showed that we have established a sophisticated, direct communication linkage between brains,” Nicolelis said in a statement. “Basically, we are creating what I call an organic computer.”
The scientists first demonstrated that rats can share, and act on, each other's sensory information by electrically connecting their brains via tiny grids of electrodes that reach into the motor cortex, the brain region that processes movement.
The rats were trained to press a lever when a light went on above it. When they performed the task correctly, they got a drink of water. To test the animals' ability to share brain information, they put the rats in two separate compartments. Only one compartment had a light that came on above the lever. When the rat pressed the lever, an electronic version of its brain activity was sent directly to the other rat's brain. In trials, the second rat responded correctly to the imported brain signals 70% of the time by pressing the lever.
More here.