Near Death
A recent article was published reguard near-death experiences, or NDEs. It suggests that a NDE is a biological process. The research found a strong corolation between people that have had a NDE and a weaker sleep-wake barrier.
Light at end of the tunnel over near death experiences
"It found that people with near-death experiences were more likely to have a sleep-wake system in which the boundaries between sleep and wakefulness were not as clearly regulated, and the dream sleep state - when there is rapid eye movement - can intrude into normal wakeful consciousness."
Light at end of the tunnel over near death experiences