Yale scientists claim pig brains can be kept alive without the body

When the body dies, so does the brain – or so you would assume. That appears not to be the case, as researchers from Yale University have claimed that they have successfully managed to keep pig brains alive without the body for up to 36 hours. The most incredible thing about this: the brains were revived around four hours after they left the slaughterhouse.

There’s a lot to unpack there, but let me make one thing clear from the offset: although the brain is alive on a cellular level, there is no evidence of consciousness. EEG scans showed a flat brain wave, of the kind you would expect from a comatose patient. “That animal brain is not aware of anything, I am very confident of that,” Yale neuroscientist Nenad Sestan told the MIT Technology Review.

But the cells were definitely alive – the team discovered that billions of individual brain cells were still healthy and theoretically capable of performing normally. And in fact, there may be a very good reason the brains were producing no signals: the researchers put chemicals in the artificial blood powering the brains to prevent swelling, but this also dampens neuron activity. “You have to understand that we have so many channel blockers in our solution,” Sestan told a National Institute of Health (NIH) meeting. “This is probably the explanation why we don’t get signal.”

One more caveat before I get into the specifics of the experiment: the paper hasn’t been peer-reviewed yet, but it has been submitted. Because of this, the researchers are cagey about going into specifics, but Sestan gave enough details at the NIH meeting that we know some basic details.

Firstly, the technique – known as BrainEx – involved between 100 and 200 pig brains. Secondly, the methodology doesn’t sound a million miles away from how you would keep any other organ alive. The scientists apparently connected the brains to a closed loop of tubes which circulated heated artificial blood through the brain’s vessels, meaning that oxygen could flow throughout the brain as it would in a living body.

The most interesting point about this: “This is probably not unique to pigs,” Sestan believes.

The need for an ethical framework

So what good is keeping brains alive if they can’t function as brains? Well while the focus of Sestan’s work was creating a brain model to analyse the connection between brain cells, and potentially to test organs for Alzheimer’s and brain cancer, others may have even more ambitious plans.

It may be refined in such a way that brain function could be maintained. Bear in mind the pig brains were four-hours dead before they could be hooked up to the machine, and remember too that the artificial blood solution used could also be blocking brain waves.

“Hypothetically, somebody takes this technology, makes it better, and restores someone’s [brain] activity. That is restoring a human being. If that person has memory, I would be freaking out completely,” Sestan told MIT’s Technology Review.

It’s perhaps this kind of potential for pushed boundaries that has led to 17 neuroscientists and bioethicists – including Sestan himself – to publish an editorial in Nature this week making the case of new rules and greater protections for the study of human brains.

“Currently, if research on human tissue occurs outside a living person, only the processes of obtaining, storing, sharing and identifying the tissue fall under the regulations and guidelines that limit what interventions can be conducted on people,” they write. “As brain surrogates become larger and more sophisticated, the possibility of them having capabilities akin to human sentience might become less remote. Such capacities could include being able to feel (to some degree) pleasure, pain or distress; being able to store and retrieve memories; or perhaps even having some perception of agency or awareness of self.”

After outlining a number of metrics for this, the researchers end on a clear note: “We do not think that these difficult questions should halt this research.” If research is stopped, then unlocking the mysteries of the human brain will become a lot harder – and maybe even impossible, leaving us guessing at cures for psychiatric and neurological illness. “But to ensure the success and social acceptance of this research long term, an ethical framework must be forged now, while brain surrogates remain in the early stages of development.”