It is essentially an increase in electrical activity in the brain once the heart stops
Is there any truth to near death experiences? Why do many near-death survivors report having seen a distant light, or had an out-of-body experience? or even conversations with divine beings?
According to a new study, these near-death experiences might have a scientific explanation. The study, published in Proceedings of the National Academy of Sciences, found that in dying rats, there is a surge in electrical activity or brainwaves at the point of the animals’ demise. In humans, this could lead to a heightened state of consciousness.
For the study, researchers at University of Michigan induced cardiac arrest in nine anaesthetised rats. Within thirty seconds of their hearts stopping, the mice experienced a surge in brain activity that exceeded the brain level activity found while they were conscious and well. When rats underwent asphyxiation, similar results were observed.
The researchers write in the journal: ‘The brain is assumed to be hypoactive during cardiac arrest. However, the neurophysiological state of the brain immediately following cardiac arrest has not been systematically investigated. In this study, we performed continuous electroencephalography in rats undergoing experimental cardiac arrest and analyzed changes in power density, coherence, directed connectivity, and cross-frequency coupling. We identified a transient surge of synchronous gamma oscillations that occurred within the first 30 seconds after cardiac arrest and preceded isoelectric electroencephalogram’. Gamma oscillations are high-frequency brainwaves, also common in humans.
According to the study’s lead author Jimo Borjigin, if near-death experience stems from brain activity, neural correlates of consciousness should be identifiable in humans or animals even after the cessation of cerebral blood flow. She told The Telegraph: “This study tells us that reduction of oxygen or both oxygen and glucose during cardiac arrest can stimulate brain activity that is characteristic of conscious processing. It also provides the first scientific framework for the near-death experiences reported by many cardiac arrest survivors.”