Say this about the kinds of molecular mayhem that we know underlie aging: Mechanisms like whether the ends of chromosomes fray (bad) and whether genes’ on-off status breaks down (really bad) at least sound like plausible ways to impair vital organs, from skin to brains and hearts, and produce the whole sorry mess known as aging.

On Wednesday, scientists reported a driver of aging that, in contrast, even the lead researcher diplomatically calls “counterintuitive”: neuronal activity. Aging, of course, affects the brain. But the brain seems to affect aging, too, they found: In creatures from worms to mice to people, high levels of neuronal firing spell a shorter life span. Lower levels — naturally, or due to drugs that dampen neurons’ activity — increase longevity.

The discovery⁴ was so surprising that it’s taken two years to be published (in Nature) because of how much additional data the outside scientists reviewing the study requested. Geneticist Bruce Yankner of Harvard Medical School, who led the research, understood their skepticism. “If you say you have a cat in your backyard, people believe you,” he said. “If you say you have a zebra, they want more evidence.”