Understanding the Hippocampus: Functions, Anatomy, and Health
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD | Last reviewed: October 7, 2026
Quick Answer: What is the hippocampus?
The hippocampus is a paired brain structure deep in the temporal lobe that regulates learning and memory. It converts short-term memories into long-term ones, manages spatial awareness and processes facts, and works with the amygdala to link memories to emotions. [1] Healthy sleep, nutrition and mental exercise help protect it and maintain cognitive function and independence.
What the research says
Hippocampal shrinkage is already measurable in mild cognitive impairment and is roughly twice as large in Alzheimer’s disease. A meta-analysis of MRI studies (14 studies including 365 people with mild cognitive impairment and 382 controls) found the hippocampus was on average 12.9% smaller on the left and 11.1% smaller on the right in mild cognitive impairment, versus 24.2% and 23.1% in Alzheimer’s disease, compared with aging controls (Shi et al., Hippocampus, 2009) [2].
Aerobic exercise may help hold on to hippocampal volume rather than make it grow. A systematic review and meta-analysis of 14 controlled trials (737 participants) found no significant effect of aerobic exercise on total hippocampal volume, but a significant positive effect on left hippocampal volume, driven by exercise preventing the volume losses that normally occur over time (Firth et al., NeuroImage, 2018) [3].
Exercise alone has not been shown to enlarge the hippocampus in older adults at high risk of atrophy. A 2025 meta-analysis of 12 studies (774 older adults with or at risk of hippocampal atrophy) found no statistically significant effect of exercise on hippocampal volume (SMD 0.09, 95% CI −0.05 to 0.22, P = .20), and concluded that current evidence does not support exercise as a stand-alone way to increase it (Zhang et al., Medicine, 2025) [4].
What is the role and function of the hippocampus?
The hippocampus is a critical component of the brain’s limbic system, a group of structures that regulate emotions, memories, and autonomic behaviors such as heart rate and breathing. [1] Named for its resemblance to a seahorse, this S-shaped structure is approximately five centimeters long and is composed of layered cells. [1] Humans possess two hippocampi, one located deep within each temporal lobe near the temples and ears. [1]
Its primary responsibility is the management of cognitive functions, specifically the transition of information from short-term to long-term memory. This process involves organizing, storing, and eventually retrieving memories. [1] Beyond basic recollection, the hippocampus enables spatial memory, which allows individuals to understand their body’s position relative to their environment, and verbal memory, which helps in recalling the correct words during communication. [1]
Function Type | Description and Impact |
Declarative Memory | The conscious recollection of specific facts, dates, and life experiences. |
Spatial Memory | Awareness of the physical environment and the ability to navigate familiar places. |
Verbal Memory | The ability to remember and utilize the appropriate vocabulary in conversation. |
Emotional Integration | Working with the amygdala to attach emotional significance to stored memories. |
What is the anatomy of the hippocampal formation?
The hippocampus does not function in isolation but is part of a larger group of structures known as the hippocampal formation. These interconnected regions work together to process and transmit information throughout the brain. The entorhinal cortex serves as the primary gateway, allowing information to flow both to and from the hippocampus. [1]
Within the formation, the dentate gyrus plays a specialized role in processing spatial memories and assisting in decision-making. The hippocampus proper, also called the cornu ammonis, is divided into four distinct regions (CA1 through CA4) that focus on forming and organizing memories. Finally, the subiculum collects the processed information and sends messages to other brain regions to facilitate the retrieval of stored data. [1]
Region | Primary Anatomical Role |
Dentate Gyrus | Processes spatial information and supports complex decision-making. |
Cornu Ammonis (CA1-CA4) | The core area for the formation, organization, and storage of memories. |
Subiculum | Acts as an exit point, sending memory signals to other parts of the brain. |
Entorhinal Cortex | The main communication pathway for data entering or leaving the system. |
What conditions affect the health of the hippocampus?
Because the hippocampus is constantly active, it is susceptible to damage from various injuries and underlying medical conditions. Alzheimer’s disease and other forms of dementia are among the most common conditions that target this region, often leading to a significant decline in the ability to form new memories. [1] While long-term memories are stored elsewhere in the brain, damage to the hippocampus primarily disrupts short-term retention. [1]
Other factors such as brain trauma, epilepsy, and encephalitis can also impair function. [1] Even natural aging leads to a gradual decline in the size and activity of the hippocampus, which explains why minor memory lapses become more frequent as individuals grow older. [1] In severe cases, such as those involving hypoxia (oxygen deprivation) or severe PTSD, the resulting memory loss can make living independently difficult and dangerous. [1]
How can you proactively support hippocampus and brain health?
Maintaining the health of the hippocampus is closely tied to overall neurological well-being. Since this structure is highly sensitive to the body’s internal environment, managing chronic health conditions and reducing stress are fundamental steps. [1] Regular physical activity and a balanced diet provide the necessary nutrients and oxygen flow required for optimal brain function.
Mental stimulation is equally important for strengthening the hippocampus. Engaging in social activities, learning new skills, and maintaining hobbies like reading or listening to music [1] can help preserve cognitive reserves. Furthermore, prioritizing adequate sleep is essential [1], as the brain utilizes rest periods to process information and consolidate the memories formed during the day.
Conclusion
The hippocampus is a small but vital structure that serves as the foundation for learning, memory, and spatial awareness. By converting daily experiences into long-term knowledge and connecting facts with emotions, it enables individuals to navigate the world effectively. Recognizing the symptoms of damage and adopting proactive health habits are essential for protecting this “mighty” part of the brain throughout the lifespan.
Taking the Next Step
If you or a loved one are experiencing persistent short-term memory loss, difficulty navigating familiar areas, or frequent confusion, it is important to consult a healthcare professional. Early evaluation through neurological exams and imaging can help identify the underlying cause and determine the best path for cognitive support and rehabilitation.
Frequently Asked Questions
What is the primary job of the hippocampus?
The hippocampus is responsible for learning, spatial awareness, and converting short-term memories into long-term storage.
Where is the hippocampus located?
There are two hippocampi, one located deep within each temporal lobe, near the ears.
Why is it named the hippocampus?
The name comes from Ancient Greek words meaning “sea horse,” due to the structure’s curved shape.
How does the hippocampus help with navigation?
The hippocampus manages spatial memory, helping you remember your body’s position relative to objects and familiar environments.
Does the hippocampus store all memories?
No, it primarily handles short-term memory and the conversion process; long-term memories are stored in other brain regions.
What happens if the hippocampus is damaged?
Damage can lead to short-term memory loss, mood changes, seizures, and difficulty making decisions or following directions.
Can Alzheimer’s disease affect the hippocampus?
Yes, Alzheimer’s is a common condition that damages the hippocampus, often being one of the first areas affected.
Is memory loss a normal part of aging?
Some decline in memory is normal as the hippocampus naturally decreases in size and activity with age.
How do doctors test for hippocampus damage?
Providers use physical and neurological exams, psychological evaluations, and imaging like MRI, CT, or PET scans.
Can stress impact the hippocampus?
Yes, chronic stress can affect the limbic system, which includes the hippocampus, potentially impacting memory.
What is the hippocampal formation?
The hippocampal formation is a group of structures, including the dentate gyrus and subiculum, that work together to process memory.
What is the role of the amygdala in relation to the hippocampus?
The two work together to connect specific memories with emotional responses, such as fear or happiness.
Can the hippocampus be strengthened?
Healthy habits such as regular exercise, balanced nutrition, adequate sleep, and continuous learning or mental stimulation support brain health. Research suggests exercise may help preserve hippocampal volume, but it has not been shown to enlarge it on its own.
What are the symptoms of a hippocampus condition?
Common signs include losing items frequently, forgetting recent conversations, and having trouble navigating familiar places.
What treatments are available for hippocampal issues?
Depending on the cause, treatments may include medications, psychotherapy (CBT), and cognitive rehabilitation exercises.
Related Reading
Temporal Lobe: Anatomy, Essential Functions, and Care covers the brain lobe that houses the hippocampus and its functions.
Alzheimer's Disease: Symptoms, Causes, Treatment & Complete Guide explains the memory-robbing disease that often affects the hippocampus first.
Transient Global Amnesia: Symptoms, Causes, Treatment & Complete Guide describes sudden, temporary memory loss and what to expect afterward.
Temporal Lobe Seizures: Symptoms, Causes, Diagnosis, and Treatment explains seizures that start in the temporal lobe and how they are treated.
Sources
Cleveland Clinic. Hippocampus. Cleveland Clinic. Last updated May 14, 2024. https://my.clevelandclinic.org/health/body/hippocampus
Shi F, Liu B, Zhou Y, et al. Hippocampal volume and asymmetry in mild cognitive impairment and Alzheimer's disease: Meta-analyses of MRI studies. Hippocampus. 2009;19(11):1055-1064. PMID 19309039. https://doi.org/10.1002/hipo.20573
Firth J, Stubbs B, Vancampfort D, et al. Effect of aerobic exercise on hippocampal volume in humans: A systematic review and meta-analysis. Neuroimage. 2018;166:230-238. PMID 29113943. https://doi.org/10.1016/j.neuroimage.2017.11.007
Zhang H, Liu J, Zhang W. The impact of exercise intervention on hippocampal volume in the elderly: A meta-analysis. Medicine (Baltimore). 2025;104(51):e46333. PMID 41431091. https://doi.org/10.1097/MD.0000000000046333
Medical disclaimer
The information provided in this article is for educational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions regarding a medical condition.
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