A new research conducted by the American neuroscientists has uncovered the clue to the long - term mystery of ‘near - death experiences’(NDE).The research carried out on dying rats indicates a surge of electrical activity in the brain could be responsible for those experiences described by near - death survivors, scientists of the University of Michigan Health System reports. To explore the truth of so called experiences before brain death, the scientists monitored the recordings of brain activity called electroencephalograms(EEGs) from nine anesthetized rats undergoing experimentally induced cardiac arrest. While the researchers found high levels of brainwaves at the point of the rats’ death, they suggested that in humans this symptom could give rise to a heightened state of consciousness. When the heart stops beating and blood stops flowing to the brain(clinical death), the animals show brain activity patterns characteristic of conscious perception, scientists clarify. The recent study, for the first time, demonstrates what happens to the neurophysiological state of the dying brain, according to the paper published in the Proceedings of the National Academy of Sciences. From bright white lights to out - of - body sensations and feelings of life flashing before the eyes are the phenomena reported by about 20 percent of cardiac arrest survivors during clinical death. With recent developments in cardiac resuscitation techniques, the number of reported NDEs has increased. " A lot of people thought that the brain after clinical death was inactive or hypoactive, with less activity than the waking state, and we show that is definitely not the case, ” said the lead author of the study, Dr Jimo Borjigin, of the University of Michigan. The study revealed that brain is capable of well - organized electrical activity during the early stage of clinical death, she explained. The researchers found that reduction of oxygen or both oxygen and glucose during cardiac arrest can stimulate brain activity that is characteristic of conscious processing. " The study will form the foundation for future human studies investigating mental experiences occurring in the dying brain, including seeing light during cardiac arrest, " Borjigin says. " It also provides the first scientific framework for the near - death experiences reported by many cardiac arrest survivors, " she concluded. Near - death experiences have been long - term challenge among different groups of scientists. The earliest narration of NDE dates back to the 4th century BCE in Plato ' sThe Republic, wherein he describes a soldier telling of his near-death experiences.