Old infarct cavity showing marginal glial scar: An infarct several months old consists primarily of a cavity with scattered remaining macrophages and a few strands of collagen at the periphery of the cavity. (Note that fibroblasts do not play a significant role in the organization of an infarct in the brain, but do respond to a slight degree.) The astrocytic glial scar is formed at the margin of the infarct which, in this slide, lies in the intact tissue in the lower part of the slide. Astrocytic cytoplasm is not as plump as in earlier stages of organization, since the glial scar is nearly completely formed.