Scientists at the University of Michigan who did studies of the brains of patients who survived cardiac arrest showed that within 30 seconds of their heart’s stopping, the brain has a period of superorganization and extensive, coordinated activity—in fact, the degree of activity surpassed what happens in the brain during normal waking state*. This fascinating phenomenon may be the basis for a brief period of hyperconsciousness and insights at the moment of death.
*Borjigin, Jimo, et al. “Surge of neurophysiological coherence and connectivity in the dying brain.” Proceedings of the National Academy of Sciences 12 August 2013. Online.