London, Sept 18 : An international team of scientists at University of Southampton have launched a study to unravel the mystery of near death experiences in heart attack patients.
While people often claim to have seen a bright light at the end of a long dark tunnel, while others recall looking down from the ceiling at medical staff following a near-death experience.
The scientists are studying what happens to the brain and consciousness when someone is on the verge of dying.
For the study, the team has set up special shelving in resuscitation areas. The shelves have pictures, which are visible only from the ceiling.
"If you can demonstrate that consciousness continues after the brain switches off, it allows for the possibility that the consciousness is a separate entity," BBC quoted lead researcher Sam Parnia, from University of Southampton as saying.
"It is unlikely that we will find many cases where this happens, but we have to be open-minded.
"And if no one sees the pictures, it shows these experiences are illusions or false memories.
"This is a mystery that we can now subject to scientific study," Sam added.
Sam said that contrary to popular perception, death is not a specific moment.
"It is a process that begins when the heart stops beating, the lungs stop working and the brain ceases functioning - a medical condition termed cardiac arrest," said Sam.
"During a cardiac arrest, all three criteria of death are present. There then follows a period of time, which may last from a few seconds to an hour or more, in which emergency medical efforts may succeed in restarting the heart and reversing the dying process.
"What people experience during this period of cardiac arrest provides a unique window of understanding into what we are all likely to experience during the dying process," Sam added.
The researchers will analyse the brain activity of 1,500 heart attack survivors, and see whether they can recall the images in the pictures.