Coloured magnetic resonance imaging (MRI) scans showing the distribution of lesions in the brain due to strokes. The redder the area, the more frequent lesions are. A stroke, or cerebrovascular accident (CVA), is where the brain is damaged by hypoxia (lack of oxygen) due to an interruption of, or other damage to, the blood supply. The location of the stroke has consequences for survival and recovery rates. Data for this image come from the Anatomical Tracings of Lesion After Stroke (ATLAS) dataset.