Doctor says near-death experiences are in the mind - CNN.com

According to this article, some scientists believe that the stereotypical images seen during a near-death experience, going through a tunnel and seeing a bright light, are produced during REM sleep.

I wonder if people from different cultures have different NDE. If not, I'm thinking it is biochemical in nature. I've read that this tunnel vision is also the result of the brain shutting down at the moment of death and the euphoria connected to it is nature's way of allowing the person to let go.