Study reveals a driver of brain cell damage in neurodegeneration

Scientists have long known that the complement cascade, a set of immune system proteins, protects against infection in the body. But in recent years, researchers have uncovered new roles for the system in the brain, including helping to whittle down connections between brain cells, or synapses, to help shape the nervous system early in life. They've also found that the pathway can become dysregulated in the adult brain, leading to cell damage and cell death seen in conditions such as Alzheimer's disease and schizophrenia. But researchers didn't know how exactly that happens.