The Download: mice with part-human brains and climate tech innovators

Scientists at Stanford have created mice with nearly half their brain cortex replaced by human cells.

This experiment builds on previous work where human brain organoids (tiny, lab-grown clusters of brain cells) were injected into baby mice and survived.

The new study genetically modifies mice so their brains do not fully develop, allowing human cells to integrate more effectively.

The goal is to study brain injuries and diseases, but it raises ethical questions about the limits of mixing human and animal tissues.

The mice were observed in a small arena, with their movements tracked by computers to analyze behavior.

This research could provide insights into how human brain cells function in a living organism, though it stops short of creating fully human-like intelligence in animals.