Around midnight on November 5, 1999, Erik Ramsey was in the passenger seat of a friend’s Camaro as they returned home from a movie on a dark, two-lane Georgia highway. They didn’t see the minivan making a U-turn until it was too late. The Camaro slammed into the minivan’s right front fender, flipped, and landed on an embankment. Firefighters needed the Jaws of Life to cut Ramsey free of the wreck.

He was screaming and writhing in pain when his father, Eddie, got to the emergency room. It took fifteen hours of surgery to repair a collapsed lung, a lacerated spleen, a ruptured diaphragm, ripped tendons in his hand, and a femur that was broken in two places. Erik woke up in intensive care, but he didn’t speak, ask for pain medication, or respond to the doctors, his father, or his mother, Sandra. Tests later revealed that a blood clot had caused a brain-stem stroke that cut the connection between his mind and his body.

After a few weeks, the Ramseys took their son home, and with the help of a home health aide, began the daily routine of feeding him through a tube, bathing him, moving his limbs through range-of-motion exercises, keeping his eyes moist with drops, and clearing his lungs with a nebulizer. Soon, he learned to use his eyes to select from a letter board that his father designed, spelling out requests for movies (anything with vampires or other bloodthirsty creatures) and music (Ozzy Osbourne is a favorite). He’d occasionally play small pranks by spelling titles that didn’t exist. And when these tricks were discovered, Erik’s father recalls, “he would just die laughing,” an involuntary, spasm-like response that he still has when something amuses or excites him. But then two bouts of pneumonia robbed him of the stamina and reaction time needed to spell out words with the letter board. He was back to the limited and laborious yes or no of his eyes.

Ramsey would be the first person to have an electrode implanted in a brain region known to be involved in speech. In December 2004, surgeons put a hollow glass electrode with three wires, measuring about a millimeter and a half, six millimeters deep into the left side of Ramsey’s brain.

It was a nurse in the local school district who put the Ramseys in touch with Phil Kennedy, a pioneer in brain-computer interface research, who had been implanting electrodes — first in rats, then in monkeys, and eventually in humans — since 1986, and who had National Institutes of Health backing for a start-up company called Neural Signals, based in nearby Duluth, Georgia. Kennedy’s first implants in humans had allowed paralyzed individuals to move a computer cursor with their thoughts and to work with basic text and drawing applications. Ramsey would be the first person to have an electrode implanted in a brain region known to be involved in speech. In December 2004, surgeons put a hollow glass electrode with three wires, measuring about a millimeter and a half, six millimeters deep into the left side of Ramsey’s brain.

In the months that followed, Kennedy ran tests in which he asked Ramsey to imagine trying to say various words or to think about moving his lips, tongue, or jaw. Kennedy could see that the neurons were firing during these exercises, but he couldn’t interpret exactly what speech sound, such as “pa” or “ooh” or “dee,” corresponded to which tangle of neural data. In 2006, he sought out Guenther, who along with Brumberg readily agreed to review the data that Kennedy had made available online.

The challenge, Guenther says, was that there were no distinct neuron spikes when Ramsey was trying to say one thing or another. “It’s not like there are neurons that start firing when he says ‘ah’ but no other sound,” he says. “All the neurons are firing a little bit all the time, but they change their firing rates. It’s the details in the patterns of those changes that are important.” By zeroing in on the part of the brain where the electrode was, says Brumberg, “the model gave us the guide to decode that part of the signal. It said, ‘Here’s what that part of the brain is trying to represent.’”

Over the next year, they used that guide to build the neural decoder software at the heart of the system they would bring down to Georgia to read Ramsey’s mind.