What is a "mini-stroke" or tia?

Short lived symptoms: A TIA or transient ischemic attack is what happens when the brain experiences a brief episode of ischemia, or when blood flow to an area of the brain is temporarily reduced or impeded. This results in neurological changes that typically, but not always resolve within 24 hours. Unlike a true "stroke", a TIA has no lasting cell death or permanent neurological symptoms. Risk factor for stroke. C doc.

<24 hours: It is the sudden development of focal neurologic symptoms/signs which resolve in less than 24 hours. It is usually due to debris (like broken plaque), platelets and/or thrombus that lodge in a brain vessel, obstructing circulation, but dissolving in < 1 day. Vascular spasm is often a component and it's resolution contributes to rapid improvement.