Amnesia

Amnesia is a loss of memory caused by brain damage or a very serious emotional trauma. There are many different types of amnesia, such as anterograde amnesia, retrograde amnesia, and post-traumatic amnesia (PTA). Anterograde amnesia is a loss or disturbance of memory for events that occur after a trauma, disease, or traumatic emotional event that caused the memory disturbance. This is typically referred to as short-term memory loss. Retrograde amnesia is a loss or disturbance of memory for events that occurred before a trauma, disease, or a traumatic emotional event that caused the memory disturbance. Long-term memories can be affected by retrograde amnesia. A person with retrograde amnesia may have a partial or total inability to recall past experiences.

PTA is an inability to form consistent day-to-day memories due to traumaitc brain injury. PTA can also refer to distrubance or loss of memory after a psychological trauma. The area of the brain that plays the most important part in memory formation is the hippocampus, a seahorse-shaped structure located in the each temporal lobe (an area of brain tissue located on the side of the head, behind the ear). Amnesia comes from the Greek word "a" meaning "without," and the Greek word "mnemonic" meaning "memory." Put the two words together and you have, "without memory."