Retrograde & Anterograde Amnesia by Holly Riggs

Why'd I Choose It & What Is It?

I chose this topic because the name Retrograde and Anterograde amnesia was something I had not heard of before. I became interested to find out what it was. Knowing what it is may help me (or anyone really) if I ever have to deal with someone with either retro- or anterograde amnesia.

Retrograde amnesia (retrieval failure) is the name of the phenomenon when an individual loses all memories formed before a traumatic experience. For example, if one was to endure some sort of brain injury, they would forget all or most of their past memories.

However, anterograde amnesia is when an individual endures a traumatic experience or injury that makes them unable to form new memories afterwards (Just think Fifty First Dates).

The Brain Stuff Behind It All

What Parts of the Brain are Affected?

For retrograde, the parts of the brain that are affected are usually the temporal lobe and the prefrontal cortex. Retrograde amnesia happens usually when a part of the brain experiences some sort of injury or trauma, like a blow to the head, stroke, tumours, and even alcoholism. Therefore, long term memories are unable to be retrieved. During retrograde, episodic memory is more affected then semantic memory, while procedural memories are usually not affected at all. This means they remember general info rather than certain events.

Anterograde amnesia usually happens when there is damage to the hippocampus or medial temporal lobe, but can even be drug induced, be a side affect of an emotional disorder, or be caused by lack of oxygen to the brain or seizures. New memories are unable to be saved to where the long term memories are because the connection between the hippocampus and cortex has been damaged. Anterograde patients usually lose their episodic memory and retain their semantic memories.

Research & Psychologist

The experiment that led to the discovery of anterograde amnesia was that of H.M. In 1953, he had his hippocampus removed to help control his epilepsy. However, he was left with serious memory impairments that made him unable to remember any new information that came after his operation, but still was able to recall his longterm memories.

An experiment was done in the 70's observing four amnesiac patients which had shown that those that suffer from retrograde amnesia were more able to recall old, far off memories, rather than memories that were close to their injury/trauma.

Interesting Facts!

  • Retrograde amnesia targets your most recent memories first
  • Former musician Clive Wearing, 76, suffers from both anterograde and retrograde amnesia, causing his memories only to last from 7-30 seconds
  • There's a severe version of anterograde amnesia caused by alcoholism called Korsakoff's Disease
Neurobiology 5. Lec. - The Story about H.M - Retrograde and Anterograde Amnesia [3/14]