What Is the Hippocampus?

The hippocampus is a seahorse-shaped structure in your brain that is involved in memory and learning. It helps organize and store new memories and connects them to your emotions. This article will explain more about the hippocampus and its function.

Hippocampus in the brain

SEBASTIAN KAULITZKI / SCIENCE PHOTO LIBRARY / Getty Images

Structure

The hippocampus is a small structure that has the shape of a seahorse. It is located inside the brain’s temporal lobe, which is behind your ears. The hippocampus is part of the brain’s limbic system involved in how you behave and respond emotionally.

Function

The main function of the hippocampus is to process and retrieve different types of memories. This includes:

  • Spatial memories: These memories are related to navigation and pathways. You use spatial memory to learn a city map and how to get around.
  • Declarative memories: These memories are related to facts and events. You use declarative memory to learn information for a test.

Other functions that the hippocampus performs include:

  • Consolidating memories while you sleep
  • Turning short-term memories into long-term memories
  • Connecting memories to emotions and sensations

Discovery/History

The hippocampus is considered one of the most studied structures in the human brain. Although the anatomy of the hippocampus was discovered four centuries ago, understanding its function took longer.

In 1587, Giulio Cesare Aranzio (Arantius) described the anatomy of the hippocampus in a book. The first drawing of the hippocampus appeared in 1729. By the 1900s, researchers were starting to understand more of its function. Today, researchers are continuing to learn more about the brain and the full function of the hippocampus.       

Significance

The hippocampus has a significant role in the brain. Damage to this structure can cause learning and memory problems. Historical examples show the importance of the hippocampus and what happens if it is removed.

When Henry Gustav Molaison had his hippocampus removed to treat epilepsy (a condition in which there are electrical disturbances in the brain) in 1953, he was no longer able to make new memories. He had anterograde amnesia, which was the inability of his brain to form new memories after the surgery.

Testing Relevance

Your doctor may check your hippocampus with:

  • Memory screening tests
  • Magnetic resonance imaging (MRI): detailed images taken using magnetic fields
  • Computed tomography (CT) scan: a detailed computerized X-ray scan
  • Positron emission tomography (PET scan): imaging that uses a radioactive tracer to look for cells that are active

Associated Conditions

It is possible for your hippocampus to be damaged and show the following symptoms:

  • Memory loss
  • Confusion
  • Problems forming new memories
  • Problems navigating or remembering directions and locations
  • Problems remembering words
  • Problems memorizing new information

Diseases and injuries can affect the health of your brain. The following conditions can affect the hippocampus:

  • Head trauma
  • Stress
  • Depression
  • Amnesia: Loss of memories
  • Traumatic brain injury (TBI): a blow to the head that causes severe injury
  • Alzheimer’s disease: a brain disorder that affects memory and thinking
  • Epilepsy: brain disorder that causes seizures
  • Bipolar disorder: a mental condition that causes periods of extreme mania and depression
  • Schizophrenia: a mental condition that affects thinking, behavior, and feelings

Summary

The hippocampus is a structure located inside your brain. It helps you process and retrieve memories. It is possible to damage the hippocampus through disease or injuries.

A Word From Verywell 

When you are having problems with memory or learning, it can be tempting to ignore them and think they are temporary. Although some problems may go away on their own, you do not want to wait. Talk to your doctor about any concerns you may have with your brain.

It is also important to pay attention to your loved ones and notice their memory or thinking problems. Encourage them to see a doctor and discuss their concerns. An early diagnosis of a medical condition can lead to faster and better treatments.

Frequently Asked Questions

  • Can the hippocampus change size?

    Yes, the hippocampus can change size because of damage, injury, or disease. For example, Alzheimer’s disease can cause the hippocampus to shrink in size.

  • How much does a brain injury affect the hippocampus?

    The location and size of the brain injury affect how much the hippocampus may be damaged. A small concussion may not do any damage to the hippocampus. On the other hand, a traumatic brain injury can cause the hippocampus to shrink.

  • What can I do to protect my hippocampus?

    Although it is not possible to avoid all injuries or medical conditions, you can take steps to protect your hippocampus. You can:

     

    • Avoid head injuries
    • Lower stress and learn to manage it
    • Get help for depression and other mental health conditions
    • Exercise on a regular basis
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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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