News Neuroscience

Rat cells grew in mice brains, and helped sniff out cookies

Chimeric mice are helping to reveal the biology of flexible brain development

A photograph of two mice looking in the direction of the camera, one brown mouse on the left and one brown and white mouse on the right.

A mouse (right) was genetically tweaked to have no forebrain, usually a lethal condition. But rat cells helped populate its brain, a new study shows. Rat cells were less likely to integrate into the mouse on the left, which didn’t have the genetic tweak.

J. Huang et al/Cell 2024

By Laura Sanders

What does it feel like to be a rat? We will never know, but some very unusual mice may now have an inkling.