Near death experiences are near universally bunk. They only thing they prove is that the brain kicks some weird shit when it shuts down. They have all the characteristics of hallucinatory experiences, and are easily explained as such.
Actually NDEs are
not easily explained. They baffle neuroscientists.
Since when? The 70s, maybe. NDEs aren't completely understood, sure, but neuroscientists are far from "baffled" by them. Every single neurological experience described in an NDE (tunnel, bright light, hyperrealism, out of body experience, and feeling one with god or the universe) can and has been reproduced either pharmacologically or with electrical stimulation or selective inhibition of parts of the brain. If you want to feel one with the universe, you shut down the part of the brain that is responsible for telling you where
you ends and everything else begins, inhibition of certain brain functions results in hyper-real sensations and extremely vivid dreams, and so on.
Other aspects of NDEs, such as when people describe actually going to heaven, meeting dead friends and relatives, floating in clouds, etc, are always culture-specific, and are obviously dreams or hallucinations that occurred before death or after the individual was revived; the glaring mistake people make is assuming that those experiences happened
while they were brain-dead. There is absolutely no reason to believe that. When the brain is that traumatized three relevant things happen: sense of time is distorted, memories are poorly formed and corrupted, and recovery involves at the very least many hours (often days) of fluctuating states of consciousness. During this time of recovery the individual's brain will be very active, definitely dreaming, and depending on the type and extent of the damage, delusional and prone to hallucination.
So, while the exact processes that lead to NDEs are not understood (there is some preliminary research suggesting that they are caused not by lack of oxygen, but by excess CO2, which could be part of the reason only 15% of patients have NDEs), they are very easily explained as a combination of neurological events, which
are all understood individually, and vivid dreams.