The insight that some people who would have otherwise be permanently dead could be brought back to life was revolutionary.

Around the same time, scientists noticed there was another way to die: brain death.

Brain death was formally recognised by the medical community following advances in medical ventilation.

“Traumatic injury could effectively kill off the brain permanently to the point that there’s zero brain function and no blood flowing to the brain at all yet the heart is still beating because the ventilator is sending oxygen back to the lungs,” explained Professor Aufderheide.

To understand what happens to us after we die, we need to understand what happens to the brain after our heart stops.

The brain is two percent of the body’s weight, but consumes 20 percent of the oxygen.

When human beings are deprived of oxygen in a cardiac arrest, the brain gets hit hardest and starts to be irreversibly damaged and the process begins.

It was long thought that after as little as five minutes of oxygen deprivation, the brain cells start to die and you’re dead.

Scientists now know that the cells are recoverable but the initial five minutes of oxygen triggers an active dying process that plays out over hours.

This led to a “paradigm shift” in our thinking about what it means to die, explains Doctor Parnia, Director of Critical Care & Resuscitation Research at the NYU school of medicine.

According to the professor, who has spent decades researching the science of death, the very idea that it’s possible to extend the window between when the heart stops and brain dies brings up a host of complex ethical issues.

Scientists at Yale University found themselves on the sharp end of this after developing technology that partially restored brain activity in pigs 10 hours after they were decapitated at a slaughterhouse is still reverberating in the scientific community.

In a call to reporters after his findings were announced, Nenad Sestan, a professor of neuroscience at Yale University and senior author of the study, stressed that “this is not a living brain, but it is a cellularly active brain”.

“I want to make clear that the organised electrical activity that would be correlated with any kind of consciousness was never detected in the course of the research,” said Steven Latham, the bioethicist on the Yale team who added that inducing consciousness was never their goal.

The finding nonetheless suggests that life in some form lingers on long after the body has shut down.

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