Anterograde amnesia is a form of amnesia, in which the individual has a deficit in learning new information. This happens as a result of brain injury, and the learning of information after the injury is disrupted. Memories for events that occurred before the injury may be unaffected, but memories of events that occurred since the injury may be lost. Short-term memory is usually also unaffected. This means that a person may remember his childhood, and the years until the injury vividly (like any other person), and yet have little or no recollection of the years following the injury. In addition, although the person may be able to carry on a conversation, as soon as he is distracted, he cannot carry on the conversation, his short-term memory having been taken up by the distraction.
In addition, is seems that anterograde amnesia only destroys memory used for facts or events. It usually does not affect memory for skills. This is not surprising, as it is known that these two types of memory are not the same. Thus, an individual with amnesia can be taught a new skill, such as how to play a new game. The next day, although having no memory of the having been taught the skill, he can often perform it quite well.
Anterograde amnesia usually occurs after damage to one of three areas:
- The hippocampus, which is known to be at least partially responsible for short-term memory becoming long-term memory.
- The basal forebrain, which produces acetylcholine which is important for learning.
- The diencephalon. It is not known why this should cause anterograde amnesia.