Don't Call Cell Activity in a Dead Brain 'Partial Life'

Arthur L. Caplan, PhD


May 08, 2019

This transcript has been edited for clarity.

Hi. I'm Art Caplan. I'm from the Division of Medical Ethics at NYU Langone Health in New York City.

A study about pig brains appeared recently,[1] and it got incredible attention. People are still talking about it. Yale University Medical School scientists went to a slaughterhouse, took the heads of about 25 slaughtered animals, removed their brains, put them into a kind of vat, and then infused the brains with certain chemicals and applied electrical stimulation. Although these pig brains were outside the body of the pig and had been sitting with nothing done to them for 4 or 5 hours, the brains showed evidence of electrical activity in some areas.

Some of the headlines that accompanied this particular experiment were off the wall. There were such announcements as "pigs restored to partial life." Partial life? What is partial life? You're either alive or you're not. You may be in a coma, you may be permanently vegetative; but if you're dead, you're dead. And if you're in these other states of consciousness, you're alive. There is no such thing as "partly alive."

The media is suggesting falsely—along with some people who were asked to comment on the experiment, including some bioethicists—that there's this intermediate state we should start to recognize: intermediate life. Restoring disorganized electrical activity in some cells in a pig brain is an interesting finding. It's certainly something that a lot of people wouldn't have expected could be produced 4 hours after an animal had been slaughtered and died. But it doesn't prove that there's some kind of semi-life existence, just because cells are firing up.

Similarly, there was some suggestion that because the pig's brains showed electrical activity with the right stimuli, this cast doubt on the whole idea of brain death. We have enough problems explaining brain death to the public. Certainly some people are skeptical about the whole idea of brain death and the notion that once the brain has stopped working, and brain death is pronounced, it's irreversible.

The media and some commentators also suggested that if you get this electrical activity back, then maybe that kind of brain death is not irreversible or perhaps it wasn't brain death. This is dangerous because it discourages people from accepting pronouncements of death in the hospital. They read these kinds of stories and start to think that maybe their loved one is only half-dead, maybe not really dead. Or worse, it leads to other people's deaths when they are deprived of donor organs. Some people will decide against being an organ donor because they heard of an experiment where brain activity was restored after death.

Again, getting electrical activity from cells under extreme circumstances, with the right chemicals and the right electrical stimulation, doesn't prove that the animal wasn't dead after it was slaughtered. It merely proves that our organic architecture is such that cells do want to fire. It doesn't prove that somehow you can reverse death. That conclusion is way out of line from this experiment.

The last gripe I have with the coverage is that some descriptions suggested that the pig could be restored to consciousness. Well, if you want to scare the American people and frighten our patients, tell them that you can take a brain, put it in a vat, stimulate it, and make it conscious. That's an old trope in many films. I remember Steve Martin had comedy routines about this. The idea of a conscious brain in a vat is beloved by science fiction and Hollywood—by movie makers everywhere. Usually, by the way, the brain starts inching around a bit when it's in the vat to show you that it's conscious.

There is no consciousness in a pig brain just because cells are firing. Consciousness requires a higher level of awareness. Consciousness requires integrated brain activity, organized brain function. The idea that if you see cells fire, it somehow means that the brain is thinking, is just lousy medicine and lousy biology, and will, again, frighten people.

I'm not against conducting a study to learn what sorts of activity may occur in a brain from an animal that has been dead for many hours. It may be useful to understand patterns of activity; it may be that someday we could even figure out, for brain-damaged people, how to stimulate some areas of the brain to get some cells firing. But the notion that there is a definition of "partial life," that someone could be semi-alive, half-alive, a little bit alive—that notion has to be rejected. The idea that any sort of brain activity implies consciousness has to be rejected. And the notion that just because cells fire in a disorganized manner, in a kind of blob of activity, casts doubt on the idea that the animal was dead in the first place—that has to be repudiated.

I'm Art Caplan, from the Division of Medical Ethics at NYU. Thanks for watching.

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