Gertrude the pig rooted around a straw-filled pen, oblivious to the cameras and onlookers -- and the 1,024 electrodes eavesdropping on her brain signals. Each time the pig's snout found a treat in a researcher's hand, a musical jingle sounded, indicating activity in her snout-controlling nerve cells. Those beeps were part of the big reveal on August 28 by Elon Musk's company Neuralink. "In a lot of ways, it's kind of like a Fitbit in your skull with tiny wires," said Musk, founder of Tesla and SpaceX, of the new technology. Neuroscientists have been recording nerve cell activity from animals for decades. But the ambitions of Musk and others to link humans with computers are shocking in their reach.

BERLIN – A turning point for Rafael Yuste, a neuroscientist at New York's Columbia University, came when his lab discovered it could activate a few neurons in a mouse's visual cortex and make it hallucinate. The mouse had been trained to lick at a water spout every time it saw two vertical bars, and researchers were able to prompt it to drink even with no bars in sight, said Yuste, whose team published a study on the experiment in 2019. "We could make the animal see something it didn't see, as if it were a puppet," he said in a phone interview. "If we can do this today with an animal, we can do it tomorrow with a human for sure." Yuste is part of a group of scientists and lawmakers, stretching from Switzerland to Chile, who are working to rein in the potential abuses of neuroscience by companies from tech giants to wearable startups.