Aneurysmal SAH is a devastating form of stroke that that affects roughly 30,000 people in the United States every year. DCI is the leading treatable cause of poor outcome after aneurysmal SAH, resulting in death or disability in 30% of all SAH patients. Capillary pericytes are contractile cells that line brain capillaries, and their aberrant contraction can lead to impairment of capillary perfusion and overall cerebral blood flow in conditions such as acute, ischemic stroke, and have been implicated in the pathophysiology of DCI.