A transient ischemic attack has the same origins as that of an ischemic stroke, the most common type of stroke. In an ischemic stroke, a clot blocks the blood supply to part of your brain. In a transient ischemic attack, unlike a stroke, the blockage is brief, and there is no permanent damage.

The underlying cause of a TIA often is a buildup of cholesterol-containing fatty deposits called plaques (atherosclerosis) in an artery or one of its branches that supplies oxygen and nutrients to your brain. Plaques can decrease the blood flow through an artery or lead to the development of a clot. Other causes include a blood clot moving to your brain from another part of your body, most commonly from your heart.

Mar. 03, 2011