Lab-Grown Brain Tissue Can Play Pong. The Next Question Is Does It Feel.

Scientists have been growing tiny clusters of human brain cells in labs for years. The little three-dimensional blobs called organoids ares derived from stem cells, and they develop their own rudimentary neural networks. One of them played Pong in 2022. That should have been a warning.

Now researchers are connecting multiple organoids together into larger structures called assembloids, and linking, say, a cortex region to a brainstem region to model how different parts of the brain communicate. One lab recently built a multi-region assembloid about the size of a small blueberry that researchers described as a rudimentary model of a fetal brain.

And here's where things get genuinely strange: serious scientists, ethicists, and legal scholars are now publishing peer-reviewed papers asking whether these things could be conscious. Conscious like experiencing something. Feeling something. The debate is real enough that a 2025 policy forum in Science called for a global oversight body to watch the field. No oversight exists yet.

Nobody agrees on what consciousness is, which makes testing for it in a blueberry-sized blob of lab-grown neurons somewhat difficult. What researchers do agree on is that the structures are getting more complex fast, the ethical questions are outpacing the guidelines, and the institutions that regulate animal research don't clearly cover organoids on their own.

The cells are human. The tissue is real. What it experiences, if anything, is unknown.

Read the full story at Popular Mechanics, April 10, 2026 (paywalled)

Hot Take: Medicine has a long history of asking the ethical questions five years after it needed to. A blueberry-sized brain cluster that already learned a video game suggests the clock started a while ago.