Bahareh Ajami studies the cellular and molecular mechanisms underlying inflammation in neurodegenerative diseases. As a cellular immunologist, she has focused primarily on the unique aspects of the role of innate immune cells in neurological disease, as these afford an opportunity to study an immunologically protected system such as the brain. Over the past 16 years, she has published three first-author papers in Nature Neuroscience that have 1) defined the origin and maintenance of microglia in adulthood and the conditions that allow monocytes to enter the brain and generate microglia-like cells, 2) established monocyte-derived macrophages as disease promoters in Multiple Sclerosis and 3) identified distinct blood-forming cell populations with different functions in neuroinflammatory and neurodegenerative disease models. Currently, she is using a system immunological approach to explore the nature of immune responses in different neurodegenerative conditions, highlighting the importance of characterizing the immune response at single-cell resolution to design targeted therapies.