Today Show Sybill Shepherd and NDEs

[JuliaL]

No measurable brain activity occurs after 20 to 30 seconds of cardiac arrest, yet a small percentage of people report seeing and hearing things that actually occurred up to 3 minutes after cardiac arrest. The fact that some people can have complex cognitive functioning when cerebral activity is absent should at least give pause to those that think electro-chemical reactions are responsible for consciousness.

Mybold

Wha? 20 to 30 seconds(???)
Um, no

http://firstaid.about.com/od/cpr/f/How-L...Arrest.htm

Question: How long does brain activity last after cardiac arrest?

A reader asks: A friend told me that when you have a cardiac arrest, within 20 seconds all brain activity is lost due to lack of blood flow and it doesn't start again until the heart starts beating. Is this true?

Answer: Close, but not exactly.

The common medical understanding is that cardiac arrest victims become unconscious within 20 seconds of the loss of blood flow (heart stops). That's not quite the same thing as losing "all brain activity." It just means the brain is incapable of keeping you awake.

All brain activity is thought to be over by about 3-4 minutes from the moment the heart stops, which is one reason why we want to start CPR as quickly as possible. I

And some areas shut down earlier, some later. This leads to aberrant consciousness. Like, visual processing is very sensitive to brain blood flow leading to things like tunnel vision in G-LOC. Or, wonder of wonders, a tunnel during NDE malfunctions. And every cardiac arrest event is unique varying in speed of onset and degree of reduction of blood flow. No doubt, there follows a variety in the patterns of hypoxic injury and attendant hallucinatory experiences.