Mild sensory stimulation results in a redirection of blood flow into the ischemic region. Illustration of middle cerebral artery (MCA) blood flow before manipulation, during pMCAO, and following whisker stimulation treatment. MCA is pictured as the large, red, central vessel in each panel. The distal portions of MCA are indicated by the smaller branches extending from MCA. The direction of blood flow is indicated by the arrows. Neuron icons represent the underlying cortical tissue. (1) Prior to manipulation, blood flows up through MCA, into the anterior and posterior branches of the vessel, and into the most distal segments, supplying a large area of the cortex with blood. (2) Following permanent MCA occlusion (pMCAO), blood flow through MCA is interrupted, resulting in ischemia of the surrounding cortical tissue. (3) In response to whisker stimulation treatment, collateral vessels (pictured top left in each panel) form a new supply route, allowing blood to flow in reverse back into the ischemic territory.