Considering Cryonics and Neuronal Survival
From Depressed Metabolism: "The debilitating effects of a stroke are the result of the (delayed) neuronal death that follows an ischemic insult to the brain. In cryonics, biochemical or freezing damage to cells does not necessarily produce irreversible cell death because damaged cells are stabilized by cold temperatures. As such, morphological preservation of brain cells can co-exist with loss of viability. Therefore, securing viability of brain cells is a sufficient but not a necessary condition for resuscitation of cryonics patients. Future cell repair technologies are assumed to infer the original viable state of the cells from their morphological properties. This does not mean that conventional stroke research does not have any relevance for evaluating the technical feasibility of cryonics. Extensive delays between the pronouncement of legal death and the start of cryonics procedures could alter the structural properties of cells to such a degree that meaningful resuscitation is even problematic with advanced nanomedical cell repair technologies. This is one of the reasons why Alcor complements the cryopreservation process with stabilization procedures to secure viability of the brain after pronouncement of legal death."
Link: http://www.depressedmetabolism.com/2010/07/27/how-many-neurons-need-to-survive-for-cryonics-to-work/