Brain-computer interface (BCI) is a collaboration between a brain and a device that enables signals from the brain to direct some external activity, such as control of a cursor or a prosthetic limb. The interface enables a direct communications pathway between the brain and the object to be controlled. In the case of cursor control, for example, the signal is transmitted directly from the brain to the mechanism directing the cursor, rather than taking the normal route through the body's neuromuscular system from the brain to the finger on a mouse.
By reading signals from an array of neurons and using computer chips and programs to translate the signals into action, BCI can enable a person suffering from paralysis to write a book or control a motorized wheelchair or prosthetic limb through thought alone. Current brain-interface devices require deliberate conscious thought; some future applications, such as prosthetic control, are likely to work effortlessly. One of the biggest challenges in developing BCI technology has been the development of electrode devices and/or surgical methods that are minimally invasive. In the traditional BCI model, the brain accepts an implanted mechanical device and controls the device as a natural part of its representation of the body. Much current research is focused on the potential on non-invasive BCI.
At the European Research and Innovation Exhibition in Paris in June 2006, American scientist Peter Brunner composed a message simply by concentrating on a display. Brunner wore a close-fitting (but completely external) cap fitted with a number of electrodes. Electroencephalographic (EEG) activity from Brunner's brain was picked up by the cap's electrodes and the information used, along with software, to identify specific letters or characters for the message.
The BCI Brunner demonstrated is based on a method called the Wadsworth system. Like other EEG-based BCI technologies, the Wadsworth system uses adaptive algorithm s and pattern-matching techniques to facilitate communication. Both user and software are expected to adapt and learn, making the process more efficient with practice.
During the presentation, a message was displayed from an American neurobiologist who uses the system to continue working, despite suffering from amyotrophic lateral sclerosis (Lou Gehrig's disease). Although the scientist can no longer move even his eyes, he was able to send the following e-mail message: "I am a neuroscientist wHo (sic) couldn't work without BCI. I am writing this with my EEG courtesy of the Wadsworth Center Brain-Computer Interface Research Program."
DARPA , the independent research branch of the U.S. Department of Defense that helped fund the Internet, is among the organizations funding research into BCI.