First, rats were trained to associate LED lights with one of two levers, with correct actions resulting in a water reward. Then rats were split into two groups — encoders and decoders — and an array of microelectrodes were implanted to either record or stimulate neurons in the primary motor cortex.
Next, an encoder rat was shown a light, pressed a correct lever and got some water. The brain activity was transmitted to a decoder rat, prompting a lever press without any LED signal. The decoder rats pressed the correct lever without an visual cue between 60 and 72 percent of the time, with that number rising if both encoder and decoder rats were rewarded for successful transmission.
In another test, microelectrodes were implanted in the somatosensory cortex. Encoder rats were held still while their whiskers were stroked. Brain activity in decoder rats matched the encoder rats, even though their whiskers hadn't been touched.
Nicolelis is excited about the future of multiple networked brains. He is currently running implant trials in monkeys, getting them to work together telepathically to complete a task. For example, each monkey might only have access to part of the information needed to find the solution to a puzzle or game. Several linked monkeys would need to communicate with each other in order to successfully complete the task.
"In the distant future we may be able to communicate via a brain-net. I would be very glad if the brain-net my great grandchildren used was due to their great grandfather's work."