Brain–computer interface

A system that records brain activity, and sometimes stimulates it, to control external devices or restore lost functions.

• Intending to move or speak produces characteristic firing patterns in motor and speech areas, even in people who are paralysed.
• Electrodes pick up those signals, and decoding software maps them to cursor movement, text or synthesised speech.
• Implants record individual neurons clearly but need surgery; caps on the scalp are safe but the skull blurs the signal.
• Clinical trials have reached typing and speech at dozens of words per minute; long-term reliability and regulatory approval are open.