Stanford scientists transplanted human brain tissue into mice missing most of their cortex; within months, it grew to occupy more than 90% of the space

Key Points:

• Stanford scientists have developed a novel model for studying human brain development by transplanting lab-grown human cortical organoids into genetically engineered mice lacking most of their cerebral cortex, allowing the human tissue to occupy over 90% of the cortical space and integrate with the mouse brain and spinal cord.
• This breakthrough enables observation of human neuron maturation, interaction, and response to injury within a living animal, providing new opportunities to research neurological conditions such as autism, epilepsy, schizophrenia, and cerebral palsy.
• The model allows for the use of patient-specific cells, facilitating the study of disease-associated changes in human brain circuitry and testing potential therapies, demonstrated by experiments showing human tissue vulnerability to oxygen deprivation linked to cerebral palsy symptoms.
• Rare von Economo neurons, implicated in social awareness and neurodegenerative diseases, emerged naturally in the transplanted human tissue, offering a unique platform to study these cells in vivo and develop treatments for related disorders.
• Ethical considerations have been addressed through extensive consultation, emphasizing that the model aims to advance understanding of human brain disorders without creating animals with human-like consciousness, with Stanford holding patents to enable further research by other laboratories.