Microglia is a brain cell capable of organizing a potent inflammatory response. This picture shows microglia (green) derived from a Parkinson’s disease patient growing in the mouse brain 1 month after transplantation. They were labeled with the microglia markers (blue and red). We took this picture to evaluate how many transplanted human cells were microglia. We are studying the effects of a familial Parkinson’s disease mutation on human microglia grown into the mouse brain, in presence or absence of inflammatory challenge.