Even after the animals’ hearts stopped beating and no blood was reaching their brains, they appeared to show signs of conscious perception.
The study is the first to take a systematic look at the neurophysiological state of the dying brain after a cardiac arrest.
It suggests something happens at the brink of death that pushes the conscious brain to a high level of arousal.
This may trigger the visions and sensations associated with NDEs, scientists believe.
As many as a fifth of people who survive cardiac arrests report having had an other-worldly experience while being “clinically” dead.
Typically NDEs involve travelling through a tunnel towards an intense light or being separated from the body.
Others encounter long-departed loved ones or angels and undergo some kind of judgment of “life review”.
Some emerge from NDEs as transformed individuals with a completely altered outlook on life, or a new belief in religion.
But many scientists believe near-death-experiences are nothing more than hallucinations induced by the effect of the brain shutting down.
The new research involved recording the electrical nerve impulses of anaesthetised rats whose hearts were artificially stopped.
Within 30 seconds after suffering a cardiac arrest, all the animals displayed a short-lived surge of widespread, highly synchronised brain activity.