Microglia is a type of glial cell that is found in the brain and spinal cord. They act as a form of defense for the central nervous system by recognizing and destroying foreign bodies such as plaques, infections, and damaged neurons. Microglia small changes to the brain tissue,  and are able to neutralize DNA fragments, neural tangles, dead or damaged cells, and foreign materials.  

Microglia is also important in neurodegeneration, or the progressive loss of neurons from the brain, by helping to delay the progression of neurodegenerative diseases.