Brain eath is a legal definition of death that emerged in the 1960s as a response to the ability to resuscitate individuals and mechanically keep the heart and lungs working. In simple terms, brain death is the irreversible end of all brain activity (including involuntary activity necessary to sustain life) due to total necrosis of the cerebral neurons following loss of blood flow and oxygenation. It should not be confused with a persistent vegetative state.