where in the brain does a stroke occur?
â¢ Thrombotic strokes are caused by a blood clot. (thrombus) in an artery going to the brain. The clot. blocks blood flow to part of the brain. Blood clots. usually form in arteries damaged by plaque. â¢ Embolic strokes are caused by a wandering clot. (embolus) thatâs formed elsewhere (usually in the heart. or neck arteries). Clots are carried in the bloodstream. and block a blood vessel in or leading to the brain.