Hippocampus

What is the hippocampus?

Your hippocampus is a small part of your brain with a big job; it helps with your learning and memory.

It converts short-term memories into long-term memories by organizing, storing and retrieving memories within your brain. Your hippocampus also helps you learn more about your environment (spatial memory), so you’re aware of what’s around you, as well as remembering what words to say (verbal memory).

You have a hippocampus on the left and right side of your brain, located within the temporal lobe.

The hippocampus is part of your limbic system. This is a group of brain structures that regulate your smells, emotions, memories and autonomic behaviors (such as heart rate, breathing, sweating, etc.).

What does the hippocampus do?

Your hippocampus is responsible for the following cognitive functions:

• Learning.
• Short- and long-term memory.
• Visual-spatial memory (remembering the position of your body in relation to nearby objects).
• Verbal memory (remembering the right words to say).
• Declarative (or explicit) memory (the recollection of facts or experiences).

How does the hippocampus work with other parts of my brain?

The hippocampus works closely with other areas of your brain that need the information that your hippocampus creates and stores.

For example, your hippocampus and amygdala work together to connect memories to emotions, which generate an emotional response. The hippocampus is a part of your limbic system and is connected to the hypothalamus and amygdala. These structures help regulate various bodily functions, including the “fight-or-flight” response.

Imagine you see a dog for the first time. The dog wags its tail and licks your hand when it sees you. Your amygdala and hippocampus work together to store that memory in your brain, so the next time you see a dog, you remember your past experience and feel calm and happy to see the animal.

This same connection also plays a role in other emotions like fear and anger. Using the same example of seeing a dog for the first time, imagine if that dog acted aggressively toward you or a loved one. Your hippocampus is working with surrounding brain structures, especially those within your limbic system, to tell you to get away from possible danger.

Where is the hippocampus located?

You have two hippocampi (plural for hippocampus) in your brain. One is on the left side and one is on the right side. Each hippocampus sits deep within your temporal lobe. Your temporal lobe is in your skull near your temples and ears.

What does the hippocampus look like?

The hippocampus looks like a seahorse. This S-like structure got its name from the Ancient Greek words meaning “sea horse.” It’s about 5 centimeters long and made up of several cells layered on top of each other.

What is the hippocampus formation?

The hippocampus is a part of a larger group of structures called the hippocampal formation. The structures within the hippocampus work together to complete cognitive functions related to memory and learning.

The parts of the hippocampus formation include:

• Dentate gyrus: It processes spatial memories and helps you make decisions.
• Hippocampus proper (cornu ammonis): This region works to form memories, then organizes and stores your memories. Four regions help the hippocampus properly do its job, including cornu ammonis (CA) 1, 2, 3 and 4.
• Subiculum: This area collects information from the hippocampus to send messages to other parts of your brain to help with memory retrieval.
• Entorhinal cortex: This is a pathway for information to get to and from the hippocampus.

What happens if the hippocampus is damaged?

An injury, brain trauma or an underlying condition can affect hippocampus functioning, including how well you’re able to create memories, remember specific moments or process information like names, dates, places and events.

Common conditions that can damage or affect your hippocampus include:

• Alzheimer’s disease.
• Amnesia.
• Dementia.
• Encephalitis.
• Epilepsy.
• Hypoxia.
• Post-traumatic stress disorder.
• Schizophrenia.

Natural aging also affects hippocampus size and activity. It’s normal to see a decline in your memory with age due to your hippocampus not working as well or as fast as it used to.

What are common symptoms of hippocampus conditions?

If you have a condition that affects your hippocampus, you may experience the following symptoms:

• Memory loss.
• Mood changes.
• Seizures.

Also, you might have trouble:

• Holding a conversation.
• Making decisions.
• Following directions or instructions.
• Navigating familiar places.
• Recalling where you left common items.
• Remembering the answer to a question you just asked.
• Creating new memories.

While your hippocampus affects your memory, damage to it usually only targets your short-term memory. Your long-term memory isn’t stored in your hippocampus. This is why someone with a condition like Alzheimer’s disease might remember things that happened long ago but won’t remember the names of people they just met.

How do you tell if your hippocampus is damaged?

If you have any signs or symptoms of a condition that affects your hippocampus, a healthcare provider may offer the following to diagnose the underlying cause:

• Physical exam.
• Neurological exam.
• Psychological evaluation.
• Magnetic resonance imaging (MRI) scan.
• Positron emission tomography (PET) scan.
• Computed tomography (CT) scan.

Other tests might be necessary to rule out conditions with similar symptoms.

What are common treatments to manage hippocampus conditions?

The type of treatment your provider recommends will vary based on what’s causing your symptoms and what symptoms affect you. Treatment might include:

• Taking medications.
• Participating in psychotherapy (cognitive behavioral therapy).
• Practicing cognitive exercises or rehabilitation (activities to stimulate your brain).

Your provider will evaluate your situation to determine what type of treatment is best for you.

How can I make my hippocampus stronger?

Your hippocampus is part of a larger brain structure. Taking care of your overall health helps you take care of your brain. You can protect your brain and make your hippocampus stronger by:

• Managing any underlying health conditions.
• Eating balanced meals.
• Getting regular physical activity.
• Managing stress.
• Getting enough sleep.
• Learning new things.

You might participate in the following to improve your overall brain health:

• Socializing and spending time with others.
• Starting a new hobby or rekindling an old hobby.
• Reading books.
• Listening to music.

A healthcare provider can help you take care of your general health and give you advice to improve your brain health.