Human cells replace half a mouse's brain cortex

researchers at stanford university, led by neuroscientist sergiu pašca, have created mice with human brain cells, demonstrating the power of organoid technologies. the mice were genetically modified to lack most cells in their cortex and hippocampus, then injected with human brain organoids. the human cells grew, divided, and took over most of the brain space within weeks to months. surprisingly, the mice with human cells performed better on maze tests, suggesting the human tissue plays a role in their cognition. pašca believes this tech could be useful for studying brain injuries, but also cautions against using it in higher species, like primates, due to potential cognitive boundary blurring.