Brain/Computer Interface (BCI) is technology that directly connects the brain to a computer. BCI has progressed from early experiments using monkeys to a point where it is now being experimentally applied to humans.
Brown University, Cyberkinetics Neurotechnology Systems, Inc., recently released results from its "Brain Gate 2" project. An included video (scroll down in the article) shows Cathy Hutchinson, a quadriplegic woman also known as subject "S3," manipulating a robotic arm. In one sequence, she is seen using the arm to pick up a bottle of coffee and sip some through a straw, effectively feeding herself entirely through her own volition for the first time in fifteen years.
BCI is an emerging technology in its early stages, and there are still several difficulties that must be addressed before it can be applied as a therapeutic medical intervention in humans. However, this is also an area of technology where progress has been surprisingly steady, and combinations of converging technologies may lead to some rapid advancements. BCI may well progress in a manner similar to the evolution of mobile phones over the last four decades.
It doesn't take much imagination to see that the applications for such a technology extend well beyond the domain of medicine. The ability to control machines through thought alone could ultimately redefine the limits of human abilities. Cathy Hutchinson may well have just demonstrated the equivalent of a 1973 car-phone, the beginnings of a technology that could rapidly evolve to become as commonplace, and socially driving, as the smart phone.