Which part of the brain forms new memories?
General information only. This article explains the basics and is not medical advice. For anything about your own health, talk to a doctor or other qualified professional.
Quick answer
The hippocampus plays a central role in forming new long-term memories, especially memories of facts and events. It’s a curved structure deep inside each temporal lobe of the brain; its name comes from the Greek word for seahorse, because of its shape. It also helps with spatial navigation, like remembering routes.
How memories are made
| Stage | What happens |
|---|---|
| Encoding | New information is taken in |
| Consolidation | The hippocampus helps stabilize the memory, often during sleep |
| Storage | Over time, memories are stored across the cerebral cortex |
| Retrieval | Recalling the memory when needed |
The hippocampus is like a temporary organizer, helping link the pieces of an experience before they’re stored long-term. Sleep’s role is covered in why sleep is important.
Different types of memory
| Type | Example | Main brain areas |
|---|---|---|
| Episodic | Your last birthday | Hippocampus |
| Semantic | Knowing Paris is the capital of France | Hippocampus, then cortex |
| Procedural | Riding a bike | Cerebellum and basal ganglia |
| Emotional | Fear of a dog after being bitten | Amygdala, next to the hippocampus |
Movement and balance are handled elsewhere; see what part of the brain controls balance.
The famous case of H.M.
In 1953, a young man named Henry Molaison, known in research as “H.M.,” had parts of both hippocampi removed in surgery to treat severe epilepsy. Afterward, he could no longer form most new long-term memories, though he could still learn new motor skills without remembering learning them. Studies of H.M. over 50 years showed scientists that memory relies on different systems.
London’s taxi drivers
London cabbies must memorize thousands of streets to pass a test called “The Knowledge.” A study in 2000 found that experienced drivers had a larger rear part of the hippocampus, suggesting the brain can change with training.
When the hippocampus is damaged
The hippocampus can be affected by lack of oxygen, severe stress and conditions such as Alzheimer’s disease, in which it’s one of the first areas to show damage. That’s why short-term memory problems are often an early sign. Anyone with concerns about memory should speak with a doctor.
For a curious memory quirk, see what the Zeigarnik effect is.
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