In a challenge to the idea that brain death is final, researchers have revived the disembodied brains of pigs four hours after the animals were slaughtered. Although the experiments stopped short of restoring consciousness, they raise questions about the ethics of the approach — and, more fundamentally, about the nature of death itself. The current legal and medical definitions of death guide protocols for resuscitating people and for transplanting organs.
Details of the pig-brain experiments appear in a paper published on 17 April in Nature. Researchers at Yale University in New Haven, Connecticut, hooked the organs to a system that pumped in a blood substitute. The technique restored some crucial functions, such as the ability of cells to produce energy and remove waste, and helped to maintain the brains’ internal structures.
“For most of human history, death was very simple,” says Christof Koch, president and chief scientist of the Allen Institute for Brain Science in Seattle, Washington. ”Now, we have to question what is irreversible.”
In most countries, a person is considered to be legally dead when brain activity ceases or when the heart and lungs stop working. The brain requires an immense amount of blood, oxygen and energy, and going even a few minutes without these vital support systems is thought to cause irreversible damage.
Gauging awareness in a brain outside a body would probably be difficult, given that the organ’s surroundings would differ so radically from its natural environment. “We could imagine that brain could be capable of consciousness,” says George Mashour, a neuroscientist at the University of Michigan in Ann Arbor who studies near-death experiences. “But it’s very interesting to think about what kind of consciousness, in the absence of organs and peripheral stimulation.”
Read the full article at Nature.