Brain-to-brain interfaces have arrived, and they are absolutely mindblowing

In a stunning first for neuroscience, researchers have created an electronic link between the brains of two rats, and demonstrated that signals from the mind of one can help the second solve basic puzzles in real time — even when those animals are separated by thousands of miles.

Here's how it works. An "encoder" rat in Natal, Brazil, trained in a specific behavioral task, presses a lever in its cage it knows will earn it a reward. A brain implant records activity from the rat's motor cortex and converts it into an electrical signal that is delivered via neural link to the brain implant of a second "decoder" rat.

Still with us? This is where things get interesting. Rat number two is in an entirely different cage. In fact, it's in North Carolina. The second rat's motor cortex processes the signal from rat number one and — despite being unfamiliar with the behavioral task the first rat has been conditioned to perform — uses that information to press the same lever.

The experiment, the results of which are published free of charge in today's issue of Scientific Reports, was led by Duke neuroscientist Miguel Nicolelis, a pioneer in the field of brain-machine interfaces (BMIs). Back in 2011, Nicolelis and his colleagues unveiled the first such interface capable of a bi-directional link between a brain and a virtual body, allowing a monkey to not only mentally control a simulated arm, but receive and process sensory feedback about tactile properties like texture. Earlier this month, his team unveiled a BMI that enables rats to detect normally invisible infrared light via their sense of touch.

But an intercontinental mind-meld represents something new: a brain-to-brain interface between two live rats — one that enables realtime sharing of sensorimotor information. It's a scientific first, and while it's not telepathy, per se, it's certainly something close. Neither rat was necessarily aware of the other's existence, for example, but it's clear that their minds were, in fact, communicating. "It's not the Borg," Nicolelis tells Nature's Ed Yong. What he has created, he says, is "a new central nervous system made of two brains."

Said nervous system is far from perfect. Untrained decoder rats receiving input from a trained encoder partner only chose the correct lever around two-thirds of the time. That's definitely better than random odds, but still a far cry from the 95% accuracy of the encoder rats.

What this two-brain system does do, Nicolelis argues, is enable the rats to work with one another in unprecedented ways. And while neural communication between two animals on entirely separate continents is impressive in its own right*, Nicolelis says the most groundbreaking application of this technology — a 3-, 4-, or n-mind "brain net" — is still to come.

"These experiments demonstrated the ability to establish a sophisticated, direct communication linkage between rat brains," he said in a statement, "so basically, we are creating an organic computer that solves a puzzle."

"We cannot predict what kinds of emergent properties would appear when animals begin interacting as part of a brain-net," he continues. "In theory, you could imagine that a combination of brains could provide solutions that individual brains cannot achieve by themselves."

The study is published in the latest issue of Scientific Reports. (No subscription required!)

*At least for most people. For more details on the study, including feedback from underwhelmed neuroscientists, check out this great overview over at Nature.
Images and video via Nicolelis lab