Glia brain cells from schizophrenia patients were transferred to laboratory mice, causing them to become afraid of strangers, sleep fitfully, and feel intense anxiety. The mice also struggled to remember new things and showed other signs of the mental disorder. This latest advance in “chimeras,” animals created by transplanting cells from one species into another, demonstrates the value of the technique. The study was conducted to explore how brain development is diverted to cause schizophrenia, a disease primarily caused by something going wrong with neurons called glia. The researchers obtained skin cells from five people who had developed schizophrenia as children (the disease more typically strikes young adults) and three healthy volunteers. They then turned the skin cells into stem cells and next into human glia-making cells that were injected into the brains of newborn mice. One of the jobs of these specialized cells is to coat neurons with a fatty molecule called myelin, but the injected cells forgot this task. Myelin enables neurons to carry the electrical signals that constitute thoughts nd feelings, and schizophrenic brains typically have abnormally low myelinaton. The injected cells also largely failed to turn into astrocytes, disrupting synapses’ firing rhythms and resulting in a chaotic network that could be catastrophic for a developing brain. In fact, the research found 118 genes that were on when when they should have been off or off when they should have been on, compared to brain activities of healthy people.