Brain Scanner Reveals Physiology of Near-Death Experiences

Researchers at the University of Michigan discovered that near-death experiences could be due to a surge in the brain's electrical activity. In a study, researchers scanned the brains of dying rats, measuring brainwave levels up to the point of death. EEG technology enabled them to determine power density, coherence, directed connectivity, and cross-frequency coupling during near-death experiences. The researchers reported that they were able to detect, paradoxically, "neural correlates of heightened conscious processing at near-death."

People who have faced near-death experiences often describe out-of-body sensations, life flashing before the eyes and bright white lights. These experiences aren't isolated; many people who come close to dying report similar experiences. In addition, test pilots have reported similar experiences in environments with rapid acceleration, which substantially reduce blood flow to the brain.

To find out more about this phenomena, researchers at U. of Michigan monitored several anesthetized rats that underwent experimentally induced cardiac arrest.

Within 30 seconds of cardiovascular shutdown, the rats' brains experienced a surge in a type of brainwave known as gamma oscillations. This neuronal characteristic is thought to play a key role in human consciousness. In particular, this type of brain wave is believed to play an important role in linking different bits of information in the brain.

After cardiac arrest, this type of electric pulse was found at higher levels. Researchers believe that the same type of electrical surge could take place in the human brain. With a higher level of consciousness and elevated brain activity, a patient who is near death may experience traditional near-death sensations.

"This can give us a framework to begin to explain these. The fact they see light perhaps indicates the visual cortex in the brain is highly activated - and we have evidence to suggest this might be the case, because we have seen increased gamma in area of the brain that is right on top of the visual cortex," noted the study.