Biology 202
2002 First Paper
On Serendip

"Darling, what did you say was Sue's number?"
"I don't remember stripping at Dan's birthday party last year!"
"No officer, I don't know what happened after the accident. I can't even remember my name."

Amnesia is the partial or complete loss of memory, most commonly is temporary and for only a short period of time. (1). There are various degrees of amnesia with the most commonly occurrence being either retrograde or anterograde amnesia. Prior to my research into this subject I did not know much about amnesia besides what is portrayed in the Disney movie Anesthesia in which Anesthesia cannot remember her traumatic childhood. While I recognize that there is a huge difference between forgetting what to pick up at the grocery store and not remembering the past ten years of ones life, what exactly is the difference between the later and the former?

While there are several classified types of amnesia I choose to focus on retrograde and anterograde amnesia, because these are most common. Retrograde amnesia refers to the inability to remember events before the brain damage occurs, and anterograde is the inability to remember events after the brain damage. (2). Okay, so now I know the difference. One you cannot remember your past. The other you cannot remember your present. Now, the question to be posed is how exactly do these two degrees differ in relation to the way the brain operates when confronted with the trauma?

Making and storing memories is a complex process involving many regions of the brain. (3). Most experts agree that we have two stages of memories - short-term memory and long-term memory. Short-term memory is the immediate memory we have when we first hear or perceive something, however, it holds a definite limited amount of information. (2).

"What did you say the number was again? 555-2695. Okay, 555-2695. 555-2596, 555-2965. Wait, what did you say the number was again?

This is an example of short-term memory.

Long-term memory is the information we retain after a day, two weeks, or ten years. (4).

"In 1492 Columbus sailed the ocean blue."

This is an example of long-term memory as almost every child is asked to commit this fact to memory.

So, what does all this have to do with amnesia? Well, I'm glad you asked. Information flows in through the middle of our brain and branches out like a tree. Before that information goes to different areas, it goes through a channeling/filter system. In this regard, the brain is like a mailroom - this information goes into this box, and that letter goes into that box. (4). In order for short-term memory to become long-term memory, it must go through a process know as consolidation. During consolidation, short-term memory is repeatedly activated - so much that certain chemical and physical changes occur in the brain, permanently "embedding" the memory for long- term access. It is believed that consolidation takes place in the hippocampi, located in the temporal-lobe regions of the brain. Medical research indicates that it is the frontal and temporal lobes that most often damaged during head injury. (3).

As the amnesiac recovers, he or she usually recalls older memories first, and then more recent memories. (3). However, memories tend to return like pieces of a jigsaw puzzle; these bits and pieces return in random order. In general, the smaller the degree of retrograde amnesia, the less significant the head injury. Anterograde amnesia is caused as a result of the complex systems in the brain being damaged. The chemical balance in the brain is upset. As brain systems begin working, memory also starts to work. (4).

I am intrigued by the fact that short-term memory can work independently of long-term memory. While long-term memory can be achieved through the repetition of a fact that is in the short-term memory, it appears that in amnesiac patients their long-term memory tends to return faster than their short-term memory. They can remember their favorite childhood food, but cannot remember why they are in the hospital. In essence, the people who suffer from aterograde amnesia have the memory capacity similar to that of a goldfish.

So while I may not comprehend the complexity to which the brain controls our thought process, I can grasp the concept of retrograde and anterograde amnesia. What I do not understand is where is the memory contained prior to the amnesiac patient being able to retrieve the information? Does it just sit their collecting dust until the mailman comes back from his lunch break?

WWW Sources
1)Mental Health, definition of amnesia.
2)Amnesia, description of retrograde and anterograde amnesia.
3)Question of The Day, lists types of amnesia and explains retrograde and anterograde amnesia.
4)Memory,explanation of memory.

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