Photographs showing similarity in cerebral vasculature in non-Tg littermates (left) and SOD1 Tg rats (right). The major blood vessels involved in the circle of Willis were almost the same in both animals (A, B). The plasticity of the posterior communicating artery (arrows) that influences the outcome of hippocampal injury after global ischemia was similar between the two animals (C, D). ACA, Anterior cerebral artery; MCA, middle cerebral artery; PCA, posterior cerebral artery; SCA, superior cerebellar artery; BA, basilar artery.