Carl Zimmer in The New York Times:
Scientists have successfully transplanted clusters of human neurons into the brains of newborn rats, a striking feat of biological engineering that may provide more realistic models for neurological conditions such as autism and serve as a way to restore injured brains.
In a study published on Wednesday, researchers from Stanford reported that the clumps of human cells, known as “organoids,” grew into millions of new neurons and wired themselves into their new nervous systems. Once the organoids had plugged into the brains of the rats, the animals could receive sensory signals from their whiskers and help generate command signals to guide their movements. Dr. Sergiu Pasca, the neuroscientist who led the research, said that he and his colleagues were now using the transplanted neurons to learn about the biology underlying autism, schizophrenia and other developmental disorders.
More here.