Fig. 1: Alteration of the microcirculation in the adult mouse brain.

a Schematic showing injection of dextran-FITC into the bloodstream via the tail vein and live imaging of functional brain microcirculation through a cranial window. b Time-lapse imaging of the microcirculation of a cortical region in a mouse from its postnatal day (P)80 to P244. The same region was imaged once every week for 6 months. Two different vessels (white arrows and red arrowheads) became occluded, and blood flow was not restored after 102 and 137 days (i.e., which were 142 and 107 days after occlusion, respectively). Blood flow in one occluded blood vessel was restored (yellow arrows). From day 144, each image has a larger field than prior images. c One example of images of all occluded vessels in the field imaged. The lengths of these occluded vessels (white dashed lines, 1 to 4) were used to normalize all vessels in the field. The percentages of occluded blood vessels, which were normalized to all blood vessels in terms of length, are shown in the pie chart in the right panel. 5 wks, time-lapse imaging of the region shown in c over 5 weeks. d Blood-flow occlusion precedes vessel regression. DsRed, pericytes in the brain of NG2DsRedBAC transgenic mice; green, FITC-dextran signal in blood vessels. Arrows indicate a regressing blood vessel. e Summary of results for blood vessels with or without blood-flow restoration (i.e., reperfusion) within a week after detecting occlusion. n = 21: number of occluded blood vessels imaged.