Agony

Agony (agonia; Greek agonia – fight, an agony) – a terminal state which precedes approach of death and is characterized by deep disturbance of functions of the highest departments of a brain, especially bark of hemicerebrums. Along with it excitement of the centers of a myelencephalon is observed.

 
Whether you know that:

The weight of a human brain makes about 2% of all body weight, however it consumes about 20% of the oxygen coming to blood. This fact does a human brain extremely susceptible to the damages caused by shortage of oxygen.