CYBB and Stroke: Chronic hypoperfusion results in myelin and axonal damage that may account for deficits in white matter function.21,30,36 Microglial activation is an important cellular response to reduced CBF in hypoperfusion36 and stroke,48 which may contribute to axonal pathology and white matter damage by sustaining an inflammatory environment.21,30,35, –37 We found an expected pattern of white matter damage in response to hypoperfusion that affected the optic tract, the internal capsule and the corpus callosum, and that was ameliorated by the genetic absence of Nox2.