Pig brains have been partially revived several hours after death by scientists at Yale University (USA), where Professor Foster was invited as a scientific visitor over 20 years ago.
The findings are likely to trigger further international discussion concerning major conceptual questions including the distinction between 'life' and 'death'; are these binary states or do they instead lie on a continuum?
The study, published in the highly prestigious journal Nature, showed that death of brain cells could be arrested and that some connections in the brain were subsequently restored. Specifically, the researchers showed a reduction in brain cell death, the restoration of blood vessels and identified working synapses (i.e. connections between brain cells that were functional). The brains also showed a lifelike response to medication and were estimated to use up the same amount of oxygen as in a living animal. However, there was no sign of brain-wide electrical activity in an electroencephalogram (EEG brain scan); in other words, there were no signals from the brain that would indicate consciousness, a state which is intrinsic to the 'human condition'. So, fundamentally they were still 'dead brains'. Nevertheless, the surprise findings challenge the idea that the brain goes into irreversible decline within minutes of the blood supply being cut off.
The results of the study also have implications for 'near death' states after incidents such as stroke (also known as cerebrovascular accidents or CVAs) and other major brain insults including traumatic brain injury.