The pig's brain had been dead for four hours (Image: GETTY)
The macabre experiment raises the prospect of bringing humans back from the dead, offering the tantalising possibility of immortality. Circulation and cellular activity were restored using tubes that pumped a chemical solution replicating blood into the decapitated heads. As a result billions of neurons began acting normally.
Mind-boggling
Nenad Sestan
It remains unclear whether the pioneering technique would work on a recently deceased person, the US team said.
But it opens the door to salvaging mental powers in stroke patients - and the development of new treatments which boost recovery of neurons after brain injury.
The gruesome Frankenstein-style experiments open up a huge ethical debate.
Senior author professor Nenad Sestan has described the results as "mind-boggling" and "unexpected" but believed the technique could work on humans.
Prof Sestan, a neuroscientist at Yale University in Connecticut, said: "The intact brain of a large mammal retains a previously underappreciated capacity for restoration of circulation and certain molecular and cellular activities multiple hours after circulatory arrest."
His team obtained 32 pig brains from abattoirs and placed them in their system, known as BrainEx, which mimics pulsating blood flow - known medically as perfusion - at normal human body temperature of 37 degrees Celsius.
Over a six-hour period, Prof Sestan and his colleagues observed a reduction in the death of the brain cells.
There was also revival of some cellular functions including the firing of synapses - vital connections between neurons that transport
