Brain-computer interfaces (BCIs) with a longer history in science fiction (since the 1950s) and in research and animal models (since the 1970s) than practical implants for humans (1990s). A brain-computer interface links a human brain directly to a computer, where neural signals are interpreted and used to perform tasks such as manipulating a mouse. In this way, a paralyzed patient can surf the web or even move a prosthetic arm with their mind alone.
Healthy people can even use non-invasive brain-computer interfaces as another type of computer input device, like a mouse or keyboard, although this technology has yet to be commercialized. Brain-computer interfaces can also send information back into the brain, for instance using electrodes to stimulate the visual cortex to “see” a scene taken by an external video camera, allowing blind patients to possess sight again, albeit far from perfectly.
Several technologies have been successfully used to get basic signals out of the brain and into a computer. These are divided into invasive BCIs, where electrodes are implanted into the gray matter of the brain; partially-invasive BCIs, implanted inside the skull but only resting on the top of the brain; and non-invasive BCIs, involving plastic devices which slip over the head like a shower cap. In general, the more invasive the BCI, the more scar tissue, possible complications, and expense, but the greater resolution of input and output.
Beginning with implants in rats in the early 90s, brain implants were developed which allowed the control of external manipulators or cursors. Monkeys were next to get the implants, and the species continues to be the target of the most sophisticated BCI research today. The big milestone for humans came in 1998, when a patient named Johnny Ray, who suffered “locked-in syndrome” due to a stroke affecting his brain stem, was given an implant, and after several weeks of training, could use it to manipulate a cursor and spell out words. This was a transformative experience for the patient: without the implant, he would remain completely unable to contact the outside world, only able to quietly observe and reflect until death. The BCI opened a channel of communication and immeasurably improved the patient’s quality of life.
In 2002, Jens Naumann, a man who went blind in adulthood, became the first of 16 paying patients to receiver a vision implant from William Dobelle, a pioneer in the field. By this time, the miniaturization of computers and quality cameras made it possible to install the implant without necessitating a hookup to a large mainframe, as had been required for previous attempts in this direction. The implant only offered black-and-white vision at a relatively slow frame rate, but it was enough to allow the patient to slowly drive a car around the research institute’s parking lot. This was the first true commercialization of brain-computer interfaces.
In 2005, the tetraplegic Matt Nagle became the first person to control a prosthetic arm using a brain implant, developed by the company Cyberkinetics Neurotechnology under the product name BrainGate. Cyberkinetics Neurotechnology still seeks to be the first company to bring BCIs to the public in a big way.