Explainers

What xenocortical mice are, and how they were made

The mechanics of the science, written for non-specialists: the animal, the method, and what happens inside the skull.

Gloved hands working with cell culture samples in a laboratory

ExplainersSeptember 17, 20268 min read

How scientists built a mouse with a half-human brain

The method starts with donated skin cells, grows them into human brain organoids, and ends with roughly four million human neurons living inside a mouse skull.

A researcher's gloved hands holding a white laboratory mouse

ExplainersSeptember 16, 20267 min read

What are xenocortical mice? A plain-English guide

In September 2026, researchers at Stanford announced mice whose brains are half human tissue. Here is what the animals actually are, in language that does not need a neuroscience degree.