Scientists say they've managed to revive cellular activity in a group of dead brains—a development that could lead to new health treatments and even blur our notions of life and death, the New York Times reports. The Yale University team obtained freshly decapitated pig heads from a slaughterhouse, removed the brains, and injected them for six hours with a cocktail of synthetic fluids. As described in Nature, the mix served its purpose by restoring metabolic activity in some brain cells without reviving consciousness; it also stirred electrical activity in some neurons. "This is not a living brain," says lead author Nenad Sestan, per LiveScience. "But it is a cellularly active brain."
The scientific world gasped. "This is a huge breakthrough," Duke University bioethicist Nita Farahany tells the Washington Post. "Our belief was there's a point of no return. Certainly we would have believed that four hours after being decapitated, that was a point of no return. It turns out it's not." Others question the ethics of half-reviving an animal's brain, but the scientists did use nerve blockers that prevented consciousness, and planned to stop if the brains became aware. The team hopes their work will inspire new ways to treat brain injuries, strokes, and Alzheimer's, but testing on humans is years away. For now, we know brain-cell death is slower than previously thought. "It's a gradual, stepwise process," says Sestan. (Read more scientific study stories.)