I've come to see the NDE as the "brain shutting down while we're fully awake". It appears that we have the equivalent of an NDE every night while we sleep, only we don't remember it. We can see similar in lucid dreams, or out of the body experiences, when our conscious-waking-self is able to interact more directly with the reality from which we originated. When we "return" to our body we are simply re-bonding with that which we have come to temporally think ourselves to be.

NDE's appear to be a crack in the facade where, for a short time, a great deal of honesty takes place... :^)