Pig Zombies Are Here – Sort Of

Studying pigs' brains has lead scientists to a surprising discovery – that cells in the brain stay active much longer than we thought.
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Yale University researchers partially restored brain activity in slaughtered pigs after they had been dead for hours.

It wasn't a full-on pig zombie success – the brains didn't regain consciousness or any activity resembling consciousness, according to U.S. News & World Report, or demonstrate any of the coordinated electrical signaling required for higher cognitive functioning. Rather, the scientists described their findings as "spontaneous synaptic activity."

"These findings demonstrate that under appropriate conditions the isolated, intact large mammalian brain possesses an underappreciated capacity for restoration of microcirculation and molecular and cellular activity after a prolonged post-mortem interval," researchers stated in their experiment abstract in the journal Nature.

What Does That Mean?

To put it simply: These researchers' work revealed that a surprising amount of cellular function was preserved or restored in the brains of mammals that had been dead for several hours.

Nenad Sestan, a neuroscientist at the Yale School of Medicine, told NPR that researchers have known for a long time that viable cells still exist in post-mortem brain for hours following death, even though brains shut down quickly in response to a lack of oxygen. However, studying viable cells from a post-mortem brain usually leaves out the "3-D organization of the brain," according to Sestan.

In an attempt to find a more effective way to study these cells, Sastan and his colleagues began developing techniques to study brain cells while leaving them in the intact organ.

"This really was a shot-in-the-dark project," team member Stefano Daniele told NPR. "We had no preconceived notion of whether or not this could work."

How Did They Do It?

Sestan, Daniele and their team tested a variety of techniques on approximately 300 pig heads, obtained from a local processing center. In final stages of their research, these scientists placed pig heads in a chamber and connected key blood vessels in the brain to a device that pumped them with chemicals for six hours. They called this technology "BrainEx."

After six years of work, the team was able to restore molecular and cellular functions in post-mortem brains, allowing them to observe viable cells in cellularly active brains. This may provide a new way to study brain diseases or injuries in labs, and explore the brain's basic biology.

An Ethical Impasse

Ethicists are contemplating how Sestan's team's research might progress and fit into modern understandings of what separates the dead from the living. Nita Farahany, ethicist and Duke Law School professor, called the situation "mind-blowing."

"My initial reaction was pretty shocked," Farahany told NPR. "It's a groundbreaking discovery, but it also really fundamentally changes a lot of what the existing beliefs are in neuroscience about the irreversible loss of brain function once there is deprivation of oxygen to the brain."

These changes raise several ethical dilemmas: How do scientists protect animal welfare, with this research in mind? Dead animals are not subject to research protections, but if that animal's brain can be revived to some extent, that may change things. Moreover, how might this work affect organ donations from people who have been declared braindead?

"If, in fact, it is possible to restore cellular activity to brain tissue that we thought was irreversibly lost in the past, of course people are going to want to apply this eventually in humans," Farahany said.