Amnesia

amnesia

Amnesia refers to the loss of long-term memory caused by disease, physical injury, or psychological trauma. Depending on the type of amnesia, a person may lose old memories, fail to form new ones, or both.

One of the most famous clinical cases is K.C., studied extensively by Endel Tulving and colleagues (2002). After a motorcycle accident, K.C. lost all episodic memories from his entire life. He could remember facts, such as the difference between a car and a truck, but he could not recall a single personal event, past or present. This dramatic case helped researchers understand the separation between episodic and semantic memory systems.

There are two major forms of amnesia: anterograde and retrograde.

 

anterograde amnesia

Anterograde amnesia refers to the inability to form new long-term memories after the time of injury. Past memories are typically intact. (Antero- means “in front,” as people ARE able to recall memories from before the injury, but cannot commit new memories to long-term memory.)

It is most often associated with damage to the hippocampus, the brain structure critical for turning short-term experiences into long-term memories (McLeod, 2011). People with anterograde amnesia can hold new information for seconds (in short-term or working memory), but it disappears quickly because it cannot be consolidated into long-term storage.

What can people with anterograde amnesia still do?

Although they cannot form new episodic or semantic memories, they often can learn new procedural skills. This happens because procedural memory depends more on the basal ganglia and cerebellum, not the hippocampus (Bayley & Squire, 2002).

You learned about the classic case of H.M. (Henry Molaison) when learning about the brain. His examples illustrates this:

• He could not recognize people he met after surgery.
• He reread the same magazine as if it were new each time.
• Yet, he improved on puzzles and motor tasks day after day—even though he had no memory of ever attempting them.

This demonstrates that different types of memory rely on different brain systems.

Anterograde Amnesia in the Movies

Dory from Finding Nemo and Finding Dory is a fictional example of anterograde amnesia. She forgets new information almost instantly but retains older memories and personality traits. Although exaggerated for storytelling, Dory’s condition reflects the core idea: difficulty forming new lasting memories.

The character of Lucy from 50 First Dates also has anterograde amnesia.

retrograde amnesia

Retrograde amnesia is loss of memory for events that occurred prior to the trauma. People with retrograde amnesia cannot remember some or even all of their past. They have difficulty remembering episodic memories.

People with retrograde amnesia may forget a few days, months, or even decades of past experiences, depending on the severity of the trauma. Importantly, their ability to form new memories going forward is usually unaffected.

Retrograde amnesia most often affects episodic memories (personal experiences), while semantic knowledge (facts and general information) is more likely to be preserved. For example, someone might forget their wedding but still know what marriage is.

Anterograde: no memories AFTER. Anter looks similar to “after,” as memories AFTER the injury cannot be stored. 

Retrograde: no memories BEFORE. Remember the prefix retro- means”old” (e.g., that lamp from the 70’s is so retro) to help remind you that retrograde amnesia deals with forgetting old memories.

Retrograde Amnesia in Movies

Jason Bourne from The Bourne Identity is a well-known fictional example. After trauma, he cannot recall his past identity but still retains procedural skills like languages and combat training. This distinction reflects real neuroscience: procedural memory is often spared because it relies on different brain circuits.

Paige – The Vow

The character of Paige from The Vow is about a young woman who loses her autobiographical memory after a car accident. She cannot remember her husband or recent years, but remembers her family and upbringing. This examples portrays temporally graded retrograde amnesia, where most recent memories are most vulnerable.

However, for real-life sufferers of retrograde amnesia, like former NFL football player Scott Bolzan, the story is not a Hollywood movie. Bolzan fell, hit his head, and lost memories of 46 years of his life in an instant. He is now living with one of the most extreme cases of retrograde amnesia on record, though he’s been able to create new memories since the accident. 

Watch this video about Jing Wu and her experience with retrograde amnesia. These led her to create the MindReset blog to help others through similar types of experiences or other traumas.

You may recall that of the most extreme examples of amnesia comes from Clive Wearing, a British musician whose brain was severely damaged by a viral infection in the 1980s. The illness destroyed large portions of his hippocampus and surrounding tissue, leaving him unable to recall nearly any events from his past (retrograde amnesia)—including his own wedding, his career as a conductor, or moments with his children. Wearing also experiences profound anterograde amnesia, living in brief windows of awareness that reset every few minutes. Yet his procedural memory remains remarkably intact: he can still play the piano and conduct music with skill, even though he cannot remember learning or performing these abilities. His case is one of the most striking demonstrations of how different types of memory are stored and affected in the brain.