D

Decorticate and decerebrate posturing require intact corticospinal or brain-stem pathways; their presence therefore excludes brain death. By contrast, isolated spinal reflexes, autonomic surges such as sweating and tachycardia, and even normal blood pressure without vasoactive drugs can all persist after cerebral and brain-stem function have irreversibly ceased [Wijdicks, 2001, PMID 11556813].