What Is Amnesia? What Causes Amnesia?

When people lose their ability to memorize data they have amnesia. Amnesia also refers to an inability to recall information that is stored in memory. In simple terms, amnesia is the loss of memory. The causes of amnesia may be organic or functional.

Organic causes may include brain damage through injury, or the use of specific drugs - usually sedative drugs. Amnesia may be one of the symptoms of some degenerative brain diseases, such as Alzheimer's disease.

Functional causes are psychological factors, such as defense mechanisms.

People with amnesia also find it hard to imagine the future, because our constructions of future scenarios are closely linked to our recollections of past experiences. Researchers from Washington University in St. Louis used advanced brain imaging techniques to show that remembering the past and envisioning the future may go hand-in-hand, with each process sparking strikingly similar patterns of activity within precisely the same broad network of brain regions.

Source and More:
http://www.medicalnewstoday.com/articles/9673.php