Loss of cerebral cortex and macrophage infiltration at the infarct center. Microscopic images of the unaffected brain (A, B, C) and affected brain (D, E, F) at the level of the infarct center. Box in A and D surrounds approximate area shown in B-F. A and D: Loss of cerebral cortex (CC) and underlying white matter (W) on the infarcted side is marked and much of the area is filled with foamy macrophages (M). Inset in D is a higher magnification of foamy macrophages. Note that the ventricle (V) is larger on the infarcted side and such structures as the caudate nucleus (N) and internal capsule (IC) are atrophied when compared to the contralateral side. B and E are higher magnification of the areas in the boxes from A and D. Loss of cerebral cortex (CC) and white matter (W) on the infarcted side is more evident and macrophages (M) can be seen filling the defect. C and F: The reactive zone (R) around the area of tissue loss showed increased GFAP staining due to astrocytosis and astrogliosis indicating glial scar formation. Inset in F: Macrophages (M) contained abundant myelin when stained for MBP seen as globular red staining. A, D: bar = 1 cm; B, C, E, F: bar = 2 mm. A, D Hematoxylin and eosin; bar = 1 cm. B, E Luxol fast blue/PASH, bar = 2 mm and E, F GFAP immunohistochemistry. Bar = 2 mm. Inset in D: Hemoxylin and eosin. Inset in F: MBP immunohistochemistry.