Signicant changes in blood ow or in the integrity of cerebral vessels are believed to cause cerebrovascular disease (CVD) and to contribute to dementias including Alzheimer’s disease.1 Stroke, the most serious form of CVD, is one of the leading causes of death and adult disability worldwide. Acute treatments for stroke, however, are severely limited. Neuroprotective drugs under development show promise at halting the ischemic cascade, but as yet, no such compound has received federal approval in the United States. One of the biggest limitations to this development is the lack of understanding of the mechanisms by which cerebral vessels react to factors such as ischemia, inammation, blood pressure changes, metabolic demands, and trauma.2 In order to address these fundamental questions, functional brain imaging techniques such as fMRI and intrinsic signal optical imaging (ISOI) have emerged as tools to visualize and quantify cerebral hemodynamics.