At Stanford University, tissue of the human brain grown from stem cells was transplanted into the brains of genetically modified mice. The cells did not just survive: over three months they grew 4.7 times, occupied about 92% of the available cortical space, and formed connections with the animal’s nervous system.
What is especially interesting is that the transplant contained rare types of human neurons that almost never arise in laboratory organoids. The scientists also recorded electrical activity in the tissue and its connection to the mice’s behavior. After artificially induced oxygen deprivation, the human tissue responded with stress and inflammation, and the animals’ gait changed.
The new method may help study brain diseases on human cells in a living organism. And if cells from a specific patient are used, researchers will be able to observe individual features of the disease and look for personalized treatments.
