Credit: BIOPHOTO ASSOCIATES/SCIENCE PHOTO LIBRARY

Caption: Stroke. Light micrograph of a section through the cerebellum of the brain after a stroke. There is a large infarct (dead tissue) at left, with normal tissue at right. The infarct is a result of ischaemia, a lack of blood flow caused by a blood vessel obstruction. This is a haemorrhagic infarct, that is blood has flowed back into the capillaries after the tissue has died.