Pig brains have been kept alive outside of the body for the first time as part of a controversial new experiment.

The brains of hundreds of pigs survived for up to 36 hours after the animals had been decapitated, researchers revealed.

The radical experiments could pave the way for brain transplants and may one day allow humans to become immortal by hooking up our minds to artificial systems after our natural bodies have perished.

Scientist Dr Nenad Sestan, who led the Yale University team, disclosed his methods in a meeting at the National Institutes of Health in Bethesda, Maryland.

Researchers were able to successfully remove the heads of between 100 and 200 pigs and resuscitate their brains while detached from the body.

The organs were connected to a closed-loop system the scientists dubbed 'BrainEX' that pumped key areas with artificial oxygen-rich blood to sustain life.