If the world is hit with a zombie pig apocalypse, we know who to blame.

In a new study published in the journal Nature, a group of scientists describe how they successfully restored some activity in the brains of pigs that had been dead for hours. The study revealed stunning new information about brain anatomy, and challenged the existing belief that brain function irreversibly shuts down shortly after its oxygen supply has been cut. 

The team, lead by Dr. Nenad Sestan the Yale School of Medicine, acknowledge that researchers have been pulling live cells from dead brains hours after the subject's death. Those cells would then be studied in a dish; however, Sestan states that "the problem is, once you do that, you are losing the 3D organization of the brain." So he and his team created the experimental system called BrainEx, in which they preserved the cellular function of dead pig brains through the use of protective chemicals, nutrient infusions, and pumps connected to key blood vessels. This system prevented the brain from deteriorating, and, after six hours, restored metabolic functions.

"We found that tissue and cellular structure is preserved and cell death is reduced. In addition, some molecular and cellular functions were restored," Sestan said. "This is not a living brain, but it is a cellularly active brain." 

Sestain stressed that his team did not see any signs of electric activity that is associated with consciousness or awareness. Stephen Latham, a Yale bioethicist who worked on the study, said the team had no intention to restore consciousness, and would not attempt to do so without guidelines.

"It was something that the researchers were actively worried about," Latham said, according to NPR. "And the reason is that they didn't want to do an experiment that raises the ethical questions that would be raised if consciousness were being evoked in this brain without first getting some kind of serious ethical guidance."

Though the study has sparked controversy and many questions about the protections given to live subjects, researchers are optimistic that the findings could lead to major medical advances. 

"By doing this, we can possibly come up with better therapies for stroke and other disorders that cause cells in the brain to die," Sestan said.