None of the materialist attempts to explain NDEs can really explain them. NDEs cannot be explained by: a lack of oxygen, a dying brain, hallucinations, religious expectations, cultural expectations, hearing about medical procedures after the fact, hearing during resuscitation, brain dysfunction, retinal dysfunction causing an image of a tunnel, brain chemicals such as ketamine, endogenous opioids, neurotransmitter imbalances, or hallucinogens including DMT, REM intrusions, epilepsy or seizures, psychopathology, unique personality traits, residual brain activity during unconsciousness, the experience occurring before or after brain activity stopped, brain activity during CPR, evolutionary adaptation, depersonalization, memory of birth, medication, naloxone, defense against dying, partial anesthesia, misuse of anecdotes, or selective reporting.
http://ncu9nc.blogspot.com/2013/07/materialist-explanations-of-ndes-fail.html
NDE Anomalies. Nineteen Anomalies of near-death experiences that materialists cannot explain:
http://ncu9nc.blogspot.com/2014/04/anomalous-characteristics-of-near-death.html
Enhanced consciousness such as realer-than-real detail, 360 degree vision, and colors not seen before.
Blind people see during NDEs. (Hogan)
Memories of NDEs are more detailed than normal memories.
Visions of deceased people, sometimes deceased people the experiencer had never met or seen pictures of. (Hogan)
A life review where the experiencer feels how he affected other people from their point of view.
Veridical (verifiable) perceptions where the experiencer perceived something when their brain was not functioning, and or perceived something that they could not have perceived with their normal senses even if they were conscious.
NDEs have been experienced by people not close to death.
"Lucid consciousness, well-structured thought processes, and clear reasoning" (Beauregard), calmness and tranquility (near-death.com), when their medical condition should cause confusion and amnesia, disorientation and fear.
Spiritual transformation.
NDEs involve a subjectively conscious experience while the experiencer is objectively unconscious. Hallucinations almost always occur when the subject is awake and conscious. (near-death.com)
NDEs occur more often during flat EEGs and not during abnormal EEGs. (Hogan)
"NDEs are remarkably consistent across virtually all experiencers regardless of age, nationality, religious background, and all other demographics", including atheists. (Hogan)
"Many parts of the brain must be coherent for lucid experiences to occur yet NDEs occur when there is no EEG activity." (Hogan)
NDErs experience "heightened awareness, attention, and memory at a time when consciousness and memory formation are not expected to be functioning" and "only confusional and paranoid thinking... should occur" (Hogan)
"In some cases, a third party has observed visionary figures seen by the experiencers" (Tymn)
Healthy people attending the dying sometimes share in the NDE. (Facco and Christian)
Because of the way the brain is wired, it cannot produce an NDE. (Alexander)
Many NDEs occur during anesthesia when the patient should be unconscious. (Long)
"The most important objection to the adequacy of all ... reductionistic hypotheses is that mental clarity, vivid sensory imagery, a clear memory of the experience, and a conviction that the experience seemed more real than ordinary consciousness are the norm for NDEs. They occur even in conditions of drastically altered cerebral physiology under which the production theory would deem consciousness impossible. (Greyson)