cerebral stroke definitionmiddle cerebral artery ischemic strokemiddle cerebral artery symptomscerebral stroke syndromemiddle cerebral artery infarctmiddle cerebral artery thrombosismedial cerebral artery strokemiddle cerebral artery occlusionmiddle cerebral artery syndromemiddle cerebral artery stroke symptomscerebral artery infarctioncerebral artery occlusion