The brain is the body's most vulnerable organ due to the defined roles of neurons within circuits. Neurons are vastly outnumbered by microglia, astrocytes, oligodendrocytes, macrophages, cells of the blood brain barrier and invading immune cells. These cells display different grades of reactivities and interactions. They integrate their responses and not only change phenotypes but can also completely reprogram after damage to protect the neuronal complexity. The interactions of these satellite ...