Collaborations in progress between ethicists and biologists seek to head off challenges raised by lab-grown “organoids” as they become increasingly similar to human brain tissue.
Part of the brain’s allure for scientists is that it is so deeply personal — arguably the core of who we are and what makes us human. But that fact also renders a large share of imaginable experiments on it monstrous, no matter how well intended. Neuroscientists have often had to swallow their frustration and settle for studying the brains of experimental animals or isolated human neurons kept alive in flat dishes — substitutes that come with their own ethical, practical and conceptual limitations.
A new world of possibilities opened in 2008, however, when researchers learned how to create cerebral organoids — tiny blobs grown from human stem cells that self-organize into brainlike structures with electrically active neurons. Though no bigger than a pea, organoids hold enormous promise for improving our understanding of the brain: They can replicate aspects of human development and disease once thought impossible to observe in the laboratory. Scientists have already used organoids to make discoveries about schizophrenia, autism spectrum disorders and the microcephaly caused by the Zika virus.