Microglia are the resident macrophages of the brain, originally described by Pío del Río-Hortega (a student of Santiago Ramon y Cajal) in a series of studies in 1919. Since those pioneering studies, many others have followed to describe microglia as complex and multitasking cells with many diverse roles under physiological (e.g. their key role in synapse pruning during de-velopment) or diseased conditions. Microglia exist as sentinels or surveyors of the environment that surround neurons, be-coming reactive upon a wide array of stimuli and consequently developing an appropriate inflammatory response. In fact, a neuroinflammatory response driven by microglia is found in virtually every disease process that occurs within the central nervous system. Therefore, a better understanding of the mech-anisms goving the microglia response is the key to improv-ing the outcome of neurodegenerative conditions.