What causes a Transient Ischemic Attack (TIA)?

A Transient Ischemic Attack (TIA) is caused by temporary disruptions in blood flow to the brain, which leads to a short-lived reduction in oxygen supply and nutrients to brain tissue. This deprivation is often due to vascular changes, such as the narrowing of blood vessels or the presence of a clot that briefly blocks blood flow. As the blockage resolves, normal blood flow is restored, and the symptoms resolve, often within minutes to hours.

In contrast, a permanent blockage of blood vessels would lead to a fully-fledged stroke rather than a TIA. Similarly, infection of brain tissue or severe dehydration may cause various neurological symptoms but do not specifically result in the transient nature of symptoms characteristic of a TIA. Therefore, the correct answer highlights the critical relationship between vascular changes and the temporary nature of the resulting ischemic event.