Researchers have kept pig brains ‘alive’ for 36 hours after being removed from dead animals. Now they say they need clear ethical guidelines to cover future uses of their techniques, including potentially working on humans.

The researcher at Tale used a system they call BrainEx which involves hooking the disembodied brain up to a closed loop of tubes. Using pumps and heaters, the system carries oxygen around the brain in an artificial liquid that acts in a similar way to blood.

The idea is to give more time when researchers study the ways brain cells are connected. If the technique works as well on a human brain, the extra time could make it possible to explore some of the largest connections. In theory the brains could eventually be used for trying out cures and treatments for brain conditions where the risks are far too significant to test on a living patient.

The researchers say there’s no evidence any of the pig brains regained ‘consciousness’ in the sense of being aware what was happening. However, “billions of individual cells” were alive in the sense of being capable of their normal activity. In effect the brain was in a similar state to a human in a coma (with the obvious difference of not being attached to a body.)

It’s most likely the brains didn’t show any signs of responsiveness because they were irreversibly damaged by the period between the pig’s death and the brain being connected to the BrianEx system. However, the researchers can’t rule out that the brains would have regained ‘consciousness’ were it not for chemicals in the oxygen carrier that were designed to prevent swelling.

The researchers have now published a call for the scientific community to discuss the ethics that would (or will) be involved if the technique was applied to human brains, particularly if done so with the aim of restoring or maintaining consciousness. In particularl they highlight the issues of consent, ownership and the definition of death. They also want a debate on how existing guidelines for mixing tissue and other material between different species should apply to brains.

The debate brings to life a short story by Roald Dahl titled William and Mary which imagined a human brain being kept alive after the person had died.