We now know slightly more about what happens after death, thanks to new research that measures the electrical activity in the brains of rats before and after cardiac arrest. Spoiler: it does not flat-line. Well, not immediately.
A team of researchers from the University of Michigan conducted their life-after-death study on nine rats with electrodes connected to the surface of their brains. They were given an injection of potassium chloride stopping their heart making them clinically dead. But their brains did not die. For as long as 30 seconds after blood ceased to flow to it, the rats' brains showed signs of activity for as long as 30 seconds after their hearts had stopped. It wasn't just a blip here and there either.
"We were surprised by the high levels of activity," says anaesthesiologist George Mashour, a senior author on a paper about the experiment. "In fact, at near-death, many known electrical signatures of consciousness exceeded levels found in the waking state, suggesting that the brain is capable of well-organised electrical activity during the early stage of clinical death."
They what?! The rats' brains were even more active when they were dead than they were alive? That is correct, and it is bananas. According to one of Mashour's colleagues, this is "the first scientific framework for the near-death experiences reported by many cardiac arrest survivors." That is, this is scientific evidence that might explain the feeling of the soul leaving the body, the life-flashing-before-the-eyes effect, the light at the end of the tunnel and so forth. However, there are plenty of scientific theories about what happens after clinical death, many of which attributed life-after-death experience to a surge in brain activity.
The Michigan team says that the rat study will form a foundation for further research into what happens in the human brain. So far, there haven't been comparable observations found with dying human patients, though that might be because we have tried putting sensors directly on the brain. Either way, we now know that our definition of death doesn't quite tell the whole story. [PNAS via Wired]