Interesting Facts About Brain

A key source of information about the function of brain regions is the effects of damage to them. In humans, strokes have long provided a "natural laboratory" for studying the effects of brain damage. Most strokes result from a blood clot lodging in the brain and blocking the local blood supply, causing damage or destruction of nearby brain tissue: the range of possible blockages is very wide, leading to a great diversity of stroke symptoms. Analysis of strokes is limited by the fact that damage often crosses into multiple regions of the brain, not along clear-cut borders, making it difficult to draw firm conclusions.
Transient ischemic attacks (TIAs) are mini-strokes that can cause sudden dimming or loss of vision (including amaurosis fugax), speech impairment ranging from slurring to dysarthria or aphasia, and mental confusion. But unlike a stroke, the symptoms of a TIA can resolve within a few minutes or 24 hours. Brain injury may still occur in a TIA lasting only a few minutes. A silent stroke or silent cerebral infarct (SCI) differs from a TIA in that there are no immediately observable symptoms. An SCI may still cause long lasting neurological dysfunction affecting such areas as mood, personality, and cognition. An SCI often occurs before or after a TIA or major stroke.