The study, by New York University's Langone School of Medicine, involved people who had suffered cardiac arrest, were pronounced dead and then were revived.
According to researchers in NY, a person's brain is still active after death, meaning in many cases they can be aware that they've passed away.
No matter these answers, this study is considered the largest of its kind ever conducted, and it has interested many across the world - both scientists and other people.
So Parnia and his colleagues started the largest ever study of people in the United States and Europe who'd suffered a cardiac arrest - which is not the same as a heart attack - and were revived, and who reported having had "out of body" experiences during that time.
Now scientists have discovered that a person's consciousness continues to work after the body has stopped showing signs of life - meaning they have awareness of their own death.
The findings echo the plot line of the new Hollywood re-make of 90s cult horror Flatliners, starring Ellen Page. According to Parnia, these recollections were then verified by medical and nursing staff who were present at the time and were stunned to hear that their patients, who were technically dead, could remember all those details.
Death, in a medical sense, is when the heart stops beating and cuts off blood supply to the brain.
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"Once that happens, blood no longer circulates to the brain, which means brain function halts nearly instantaneously".
In the film a group of young doctors embark on a unsafe experiment by taking turns to chemically induce their heart to stop and flatline to find out exactly what happens in the afterlife. "Your gag reflex, your pupil reflex, all that is gone".
A person's consciousness continues to work after the body has died, study finds.
This triggers a chain reaction from a cellular process that will result in deaths of brain cells.
In the movie, a group of students take turns giving themselves a cardiac arrest to see what happens after their hearts stop. This is enough to slow the brain cells' death trajectory, but it isn't enough to kick-start the brain into working again, which is why reflexes don't resume during CPR, he said.
They're also looking for better methods of monitoring the brain beyond the threshold of death, Live Science reported, and improving resuscitation techniques to better prevent brain injury. They induced them heart attacks and observed the electrical signals inside their brains.
"At the same time, we also study the human mind and consciousness in the context of death, to understand whether consciousness becomes annihilated or whether it continues after you've died for some period of time - and how that relates to what's happening inside the brain in real time", Dr Parnia added.