Imagine an undercover operative on a mission. At some point, she knows she'll need to call for backup - but pulling out a phone would be too risky, and there's no way to give a visible signal to her team.

Yet at the key moment, she can think "YES" - which could be interpreted as "yes, now is the time, go go go go go!" - and send that signal directly to the brain of a team member, who would see it as a flash and know that now is the moment to act.

That sort of direct communication from one brain to another sounds like telepathy, but technology that can read your brain's signals and send a simple signal (that means "yes" or "no" or whatever you choose) already exists - although our hypothetical portable version with hidden electrodes that could surreptitiously help covert agents communicate does not (yet!).

As we learn more about how our brains communicate - sending and interpreting electrical signals that mean "yes," "no," and more - the technology that now enables our basic brain-to-brain communication could allow us to do much more, potentially communicating full thoughts or even more.

What we can already communicate

Right now, the sort of information we can send from one mind to another is very basic, according to a thorough look at the current state of brain-to-brain communication by Jerry Adler in Smithsonian magazine.

Someone with electrodes on their head can send a "yes" to another person across a campus. A computer senses that the person did something (blink in a certain way, for example) that signals "yes." The computer wirelessly transmits that information to a second computer. From there, the signal is sent to a magnetic coil affixed to a second person's head. When that magnetic signal is received by the second person's brain, they see it as a flash: the signal that a "yes" has been sent.

A more invasive example of something that exists involves a brain implant. UK researcher Kevin Warwick used a neural implant to send signals to a chip embedded in his wife's arm, allowing him to transmit rudimentary 'communication' from his brain to another person electronically. He also used the same technology to control a robotic arm across the Atlantic - the technology that allows the brain to send signals can also send those signals to a machine.

Yet these forms of communication are right now either very basic, like the electrodes that can transmit "yes" and "no," or invasive, as in the case of a brain implant.

Assuming that most people aren't ready to run wires into their brains, lets focus on non-invasive forms of communication. So far, they rely on magnets and tiny electric pulses, which are crude instruments. Adler reports that the smallest area these can signal in the brain is about a half-inch - which is massive compared to the individual neurons that we use for more precise (and even eloquent) communication.

Other, more precise technologies exist that might enable more complex thoughts to be sent, but they haven't been proven to be safe - yet.

What we might be able to do in the future

MatrixThe Matrix, Warner Bros./Village Roadshow Pictures

Once we can more accurately read the signals one brain is sending out and direct them to the right part of a receiving brain, we'd be able to do more than send complex thoughts - something that, after all, smartphones can already do fairly effectively.

Brain-to-brain communication could go much further though, and the potential uses for relaying information directly from one brain to another are almost limitless. As Adler writes, the "killer app for a brain-to-brain interface… must be something more global, more ambitious - information, skills, even raw sensory input."

Our brain stores more than our thoughts: it stores our muscle memories and other things we've learned too.

Could someone transmit the brain information that includes the skills to play a piano or guitar? Could we teach the perfect baseball swing or jump shot by transmitting that data from one brain to another? That may sound crazy, like something right out of The Matrix. But at least in rats, researchers have shown that they can play the memory of doing a task from one rat's brain into another, and that second rat can learn the same task far more quickly. That's animal research that's incredibly far from what we're talking about in humans, but it's most definitely intriguing.

Could brain-to-brain communication even help us go beyond humanity and see how an animal views the world? We could potentially use this same technology to send brain signals from animals into human brains. Perhaps we could transmit what happens in a dolphin's brain as they scour the ocean with sonar or get a sense of the detailed smells a bloodhound is aware of. While the possibility is irresistible, the technology is nowhere near letting us learn about the secret lives of dolphins.

Still, if we could figure out a way to transmit that information, our very powerful brains might just find a way to make sense of it. Neuroscientist David Eagleman thinks our extraordinary processing power might even make it possible to develop new senses. The same technology that would enable brain-to-brain communication could perhaps allow us to build external devices that give us ways to see infrared or hear sounds no other person hears.

A lot of this is far, far away - but basic forms of brain-to-brain communication are already reality. Blink once if you agree.

Read the full Smithsonian report.

This story was originally published by Business Insider.

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