My science fiction novel Nexus is out today. It's a story about the struggle over a technology that can get information in and out of the human brain – senses, thoughts, emotion, all sorts of information. (Read an excerpt here.) That's science fiction, right?
Yes and no. The technology I describe – a ‘drug' that's really a collection of nanodevices that attach to the neurons in your brain – is definitely fictional. But it's also based on real science that's been moving ahead faster than most of us have noticed – science that is already getting sight, sound, and touch in and out of the brain, and that's starting to go beyond that and into the realms of memory and even some types of intelligence.
The Brain is Electro-Chemical
We've known that the brain is electrical since 1870. That was the year that two radical German scientists, Fritsch and Hitzig, proposed an experiment to electrically stimulate part of the brain of an anesthetized dog. The University of Berlin, horrified at this idea, wouldn't allow the use of its facilities. So the pair used the dining room table of Fritsch's home. There they demonstrated that a very low current applied to part of the brain would cause the dog to reliably move one of its limbs. The brain was electrical.
Decades later, in 1930, a brilliant surgeon named Wilder Penfield took this a step farther. Penfield operated on epileptic patients, carefully cutting out small parts of the brain that caused their seizures. To find the responsible areas, and to minimize the damage as much as possible, Penfield took to using a small electrical current to map the different brain regions of patients as he operated on them. What he found was that stimulus to the right areas would cause patients to have vivid memories, or suddenly start speaking, or suddenly experience a sight or smell or sound. It wasn't just motion that was electrically driven. It was sensation. It was speech. It was, to use a loaded word, consciousness.
Those discoveries would lead to medical advances decades later. In the 1970s, Dr. William House introduced the cochlear implant. The cochlear implant looks like a hearing aid, and you'd be forgiven for thinking that it is one. But the way it works is profoundly different, and says something deep about our ability to interface with the brain.
We hear when vibrations in the air stimulate the hair cells of our inner ear. That stimulation, in turn, results in an electrical signal being sent along the 30,000 or so nerves of the auditory nerve bundle and into the auditory cortex of the brain. People with some hearing damage may have lost some of those hair cells. Normal hearing aids work by picking up sounds via a microphone, cleaning up and enhancing that sound, then playing the cleaned up version – potentially at a higher volume – into the ear. The remaining hair cells of the inner ear then pick up the sound and transmit it to the brain.
But what if you have absolutely no hair cells at all? For millions of people, that's the case. No hearing aid can help them, because no hair cells remain to pick up any vibrations in the air. That's where the cochlear implant comes in. Instead of cleaning up and replaying sounds, it uses electrodes to send an electrical signal straight into the auditory nerve bundle and from there into the brain. And while a typical cochlear implant has only 22 electrodes – less than 1/1000th the number of nerves in the auditory nerve bundle – it produces hearing that's good enough to hold conversations. Worldwide, more than 200,000 people already have cochlear implants sending data into their brains. And its impact is absolutely life changing.
Want to see? Here's a video of an 8 month old baby hearing for the very first time.
The first cyborgs are among us.
Progress on sending data into the brain didn't stop there. It's extended into ways to get visual data into a human mind.
In 2002, a man named Jens Naumann, who'd lost both eyes in a pair of unrelated accidents nearly 20 years earlier, had his vision restored. The system that restored it, designed by an eccentric scientist named William Dobelle, used a CCD camera worn on Jens' glasses to capture video. That video was sent to a small computer Jens wore, which translated the imagery into a series of electrical impulses that were sent, through a jack in the back of Jens' skull, Matrix style, to his primary visual cortex. And with those electrical impulses, carefully arranged in a pattern that matches his visual cortex, Jens can see.
Think about that. We can, today, take digital images and send them directly into a human brain.
More recently, physicians have switched to an approach more similar to the cochlear implant. Instead of opening up the skull to put an implant in the visual cortex of the brain, most research now uses a retinal implant – a chip placed at the back of the eye – to send data along the visual nerve and into the brain. And those implants, now tested on dozens of patients, are moving along the path towards full clinical approval. A decade from now we may have tens of thousands or even hundreds of thousands of formerly blind men and women wearing retinal implants, essentially the ‘bionic eyes' of fiction.
We've also gotten data out of the human brain. In 1997 a Georgia drywall contractor, Vietnam veteran, and occasional blues guitarist named Johnny Ray suffered a massive stroke in his brainstem. One minute he was on the phone, having a perfectly normal conversation. Then nothing. When he awoke, he was in the Veterans Affairs Medical Center in Atlanta. He was paralyzed from the neck down. An emergency tracheotomy that had saved his life had also taken away his voice. He could think, but his interaction with the outside world had shrunk dramatically. The only way he could communicate at all was to blink his eyes – once for no, twice for yes.
There are around a quarter million quadriplegics in the United States. Worldwide there are around half a million "locked in" patients like Johnny Ray who are both paralyzed from the neck down and unable to speak. For all of those, there may be hope.
That hope started with a neuroscientist named Phillip Kennedy. Kennedy, working in monkeys, had shown that he could implant electrodes in the motor cortex of a monkey brain – the part that controls motion – and teach them to use that electrode to control a computer cursor or a robot arm.
That's exactly what he did with Johnny Ray. With the help of a surgeon, Kennedy placed a single, wireless electrode in the part of Jonny Ray's motor cortex that controlled his right hand. Then, over painstaking months, they trained Johnny Ray to use that electrode to control a computer cursor, and use that to type out messages to his doctors, family, and friends. He went from being able to communicate only by blinking to being able to type out whole messages.
Today those systems are even better. Using 32 or 64 electrodes and more advanced computer algorithms, they can be implanted, calibrated, and working well in minutes rather than the months it took Johnny Ray. And now those systems, too, are moving through human trials. Recently io9 posted this video of a patient using a more recent version of this technology to control a robot arm.