The brain requires a large amount of energy and oxygen for survival. In order to meet these requirements, the blood supply to the brain is tightly controlled to ensure that active areas receive more blood. Recently, cells known as pericytes, which are found on small blood vessels, were shown to play a role in the control of brain blood flow. However, very little is known about these cells. Our recent work suggests that two different types of pericytes exist and each type may play a different role in the control of blood flow. We will study these pericytes to better understand how they are different, how they communicate with other nearby cells and how they influence blood flow. This work will shed new light on pericytes and their role in the brain.