Possible Hints of Consciousness After Death Found in Rats BY BRANDON KEIM08.12.13http://www.wired.com/wiredscience/2013/08/after-death-consciousness-rats/

While people are undergoing 'standstill' operations aka.... 

Deep hypothermic circulatory arrest ...for conditions such as brain tumors, which would offer an amazing opportunity to study
NDE's, instead we look at dead rats...who to date have never reported having a single NDE. There is a however a line in this 
article that should be noted:

“There’s still so much we don’t know.” 

The fact remains, the key reason why we don't know is simply because of a lack of funding and concerted,
efforts, possibly even an attempt withhold results regarding what has already been discovered...