My Uncle had a near death experience a few years back and with his story, my mother has been more into her faith more than ever before. She felt frightened by his story, just as I felt frightened when we read the handouts on nde’s. It really made me “think.” But I just found it too hard to believe. I did a little research on my own about the subject. I think that we were presented with only one side of the material. I found this scientific answer (of course it does not apply to all the cases we read): during the medical procedure, “oxygen deprivation turns off the brain’s inhibitory cells, neural activity increases in the visual cortex.” The result is a growing patch of light, which looks much like what you would see moving thorough a tunnel.