As Minibrains Get Larger, So Do Bioethical Quandaries : Shots - Health News Scientists are growing increasingly large and sophisticated clusters of human brain cells. Ethicists are now wondering what to do if these minibrains start thinking.
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Tiny Lab-Grown 'Brains' Raise Big Ethical Questions

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Tiny Lab-Grown 'Brains' Raise Big Ethical Questions

Tiny Lab-Grown 'Brains' Raise Big Ethical Questions

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  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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In the world of science, some tiny clusters of living human brain cells are raising big ethical questions. They're sometimes called minibrains. And as NPR's Jon Hamilton reports, they're allowing scientists to mimic aspects of the human brain in a Petri dish.

JON HAMILTON, BYLINE: In the lab, these minibrains still don't get much larger than a pea, and they contain only a few million cells. The human brain has about 85 billion. But Nita Farahany of Duke University says these bits of living tissue develop and get wired up a lot like actual brains. And she says they are helping scientists do remarkable things.

NITA FARAHANY: So if you're talking about something like schizophrenia or autism, if you want to model those things, it's difficult to do so with animal models, and it is ethically impossible to do so in many instances with living humans.

HAMILTON: But it is possible to grow a minibrain that models autism and watch how it develops. Farahany, who studies the legal and ethical implications of emerging technologies, says the potential of minibrains is mind-boggling. But she says so are some of the questions raised by creating these brain-like structures, which scientists prefer to call organoids.

FARAHANY: Is it possible that an organoid far off in the future could develop something that looks like consciousness or any kind of sentience, the ability to feel something like pain or experience anything?

HAMILTON: Farahany and 16 other prominent scientists, ethicists and philosophers summarized their thoughts in a commentary in the journal Nature. Farahany says one of their concerns involves the practice of transplanting human brain tissue into animals.

FARAHANY: How comfortable are we with certain kinds of hybrids that we're creating, and does that change the way we regard those animals or the kinds of protections that should be afforded to them?

HAMILTON: In other words, do we really want to create a mouse with exceptional mental abilities? And if we do, should it be treated like a typical lab mouse or more like a chimp? The commentary's authors don't try to answer those questions, and Farahany says there's no need to yet. She says that's because minibrains and related technologies are still in the very early stages.

FARAHANY: Right now they're pretty good proxies for being able to study how certain kinds of human neurons interact with each other and develop and grow over time. But they are still far away from what an actual human brain would look like.

HAMILTON: But the field is moving quickly. Just this month, the team at the Salk Institute in La Jolla showed that a human minibrain transplanted into a mouse brain developed functioning blood vessels. So Farahany says scientists and the rest of society need to start developing guidelines now.

FARAHANY: This is really the time to get out ahead of these ethical issues before it becomes deeply problematic, you know, to be able to proceed without having addressed them.

HAMILTON: She says minibrain research has so much potential to help people. It would be tragic to have it derailed by an ethical crisis. Jon Hamilton, NPR News.

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