On a bright summer day in July 2021, James Fisher rested nervously, with a newly shaved head, in a hospital bed surrounded by blinding white lights and surgeons shuffling about in blue scrubs. He was being prepped for an experimental brain surgery at West Virginia University’s Rockefeller Neuroscience Institute, a hulking research facility that overlooks the rolling peaks and cliffs of coal country around Morgantown. The hours-long procedure required impeccable precision, “down to the millimeter,” Fisher’s neurosurgeon, Ali Rezai, told me.

Prior to operating, Rezai and his team of neuroscientists created a digital rendering of Fisher’s brain, a neural…