The human brain is both delicate and demanding. If its blood supply is disrupted, even a little, the result can be catastrophic. Such disruption, often a burst blood vessel in the brain, is called a stroke, and can cause severe paralysis or even death.
Strokes throw light on the organisation of the brain. Each hemisphere has differing ranges of functions and it is now possible to actually visualise the inside of the working brain and to locate movement, speech, vision and even the ability to perceive spatial relationships.
Even more remarkable is the brain's own ability to combat the damage. A few stroke victims make an almost miraculous recovery and a whole range of explanations has been put forward. Could it be regeneration of dead nerve tissue, or the transfer of abilities from one part of the brain to another? The fight is now on to understand and to maximise this recovery and to increase the hope for stroke victims and their families.