Your brain contains memory centers where millions of old memories are stored away in an orderly manner according to subjects: music you have heard, sights you have seen and tastes and smells you have experienced. Because of this orderly arrangement, it is possible for one section of a person’s brain to be damaged or destroyed without harming the other sections.
For example, someone may suffer a brain injury and “forget” how to use words, but still be able to use numbers. Sometimes people have a memory blindness due to old age or an injury. This memory blindness may take the form of preventing them from recognizing objects they see. They may look at a ball and not know what it is. But if they touch it, they can recognize it as a ball because their storehouse of “touch” memories has not been damaged.
Some people suffer from amnesia, an inability to remember some or all of their past experiences. Amnesia can be caused by a shock, which makes a person forget things he does not want to remember, or by a physical injury to the brain. Doctors can often treat amnesia from a shock by hypnosis or certain drugs. But amnesia caused by physical injury causes permanent damage and cannot be cured.