A young adult man with closely cropped dark brown hair sits in a wheelchair in a dimly lit room, facing a computer screen on which a simple phrase is typed out: “How are you today?” Underneath the question on the screen, three dots appear—similar to the ones messaging apps use to signal that your conversation partner is composing a response—and flash with anticipation. One by one, new words materialize: “I am very good.”

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At first glance, this brief conversation doesn’t seem particularly special, but the man’s situation is anything but ordinary. On top of his head is a small box, about one inch square in size, connected to a circular portal in his skull about the size of a nickel. Protruding from the box is a thin black cable. The man, who goes by the nickname Pancho, is paralyzed and unable to speak, but a BCI records brain waves from the part of his cortex that is responsible for generating speech, the vocal motor cortex, and translates them into words on the computer screen.