We often talk about death as a point in time. One moment you’re alive and the next, when your heart stops beating and your lungs stop breathing, you are clinically dead. This definition tempts us to view death as a clear-cut event, like the flip of a switch.

That’s not how Jimo Borjigin, a neuroscientist at the University of Michigan, sees it. “Doctors assume that after clinical death, the brain is dead and inactive,” she says. “They use the term ‘unconscious’ again and again. But death is a process. It’s not a black-or-white line.”

In a new study, Borjigin discovered that rats show an unexpected pattern of brain activity immediately after cardiac arrest. With neither breath nor heartbeats, these rodents were clinically