They used a pig’s brain, which was perfused with lethal glutaraldehyde before being frozen at –135C, a method called aldehyde-stabilised cryopreservation (ASC). This process kills any chance of the brain being brought to life again, but they won because when the treated brain was warmed up again its connectome – the brain’s wiring diagram – was amazingly well preserved. In fact it was so well preserved that even the fine ultrastructural details of dendritic spine synapses could still be seen with a 3D electron microscope. This means potentially 150 trillion connections, all of which may be implicated in storing memory.
A human brain treated this way could never be brought back to life. Yet all its preserved information could potentially be uploaded into an artificial or virtual body indistinguishable from the previously living one – like “uploading a person’s mind” after a long wait. Would this then be “you”?
A few years ago I was asked to become an adviser to the foundation. At first I adamantly refused, but they persuaded me that they needed doubting sceptics as much as enthusiasts and I soon realised that brain preservation raises deep questions about mind, consciousness and self that interest me greatly.