Mice with millions of human neurons in their brains
12 hours ago
- Researchers implanted human cortical organoids into mice without their own cerebral cortex, creating integrated human-mouse brains with millions of human neurons.
- The model allows study of human neurons at molecular and cellular levels in a living organism, enabling research into autism, schizophrenia, cerebral palsy, and dementia.
- Human neurons comprise over 90% of the cortex in these mice, and the organoids are implanted two days after birth during a critical window of plasticity.
- Proof-of-concept experiments showed oxygen deprivation caused lesions similar to human cerebral palsy, offering a new platform for studying irreversible brain injuries.
- The mice spontaneously developed rare Von Economo neurons, linked to social behavior and frontotemporal dementia, which had never been isolated in a living organism before.
- Ethical oversight was provided by an independent panel; researchers caution against implanting human organoids into monkeys without strong justification.
- Limitations include slower growth of human neurons (equivalent to a two-year-old child at maximum mouse lifespan) and no significant behavioral changes in the mice.