Scientists have for the first time discovered evidence that microglia -- brain's immune cells -- may play roles in a variety of neurodegenerative diseases like Alzheimer's Parkinson's and psychiatric illnesses such as schizophrenia. Microglia are a type of macrophage white blood cells found throughout the body that can destroy pathogens or other foreign materials. They are known to be highly responsive to their surroundings and respond to changes in the brain by releasing pro-inflammatory or anti-inflammatory signals. The study reported in the journal Science has showed that microglia have hundreds of genes that are more highly expressed than other types