Un ratón con neuronas humanas en su cerebro

Researchers led by Sergiu Pașca at Stanford University have developed mice containing human brain tissue derived from organoids. This study follows a 2022 experiment where human brain organoids transplanted into newborn rats integrated into the animal's nervous system and responded to sensory stimuli.

According to Jaime Millás for Exaudi, the September 2026 research involved genetically modifying mice to prevent the normal development of the cerebral cortex and hippocampus. Scientists then filled these empty spaces with human neuronal tissue from organoids. This method creates an advanced neurological chimera to help researchers study the development and function of the human brain.

The ability to grow human nerve cells from stem cells and incorporate them into animal nervous systems offers new ways to study psychiatric and neurological diseases. However, the research also raises bioethical questions regarding whether human nerve tissue can change the capabilities of the receiving animal.