Hippocampus: anatomy and functions (2023)

Author:Roberto Grujicic MDCritical:Dimitrios Mytilinaios MD, PhD
Last consultation: December 5, 2022
Reading time: 18 minutes

Hippocampus: anatomy and functions (1)



Synonym:formation of the hippocampus, hippocampus proper,Show more...

HeHippocampusit is a paired structure present in each temporal lobe of the brain. It takes its name from the Greek word forSeahorse, because it looks like this little fish swimming upright.

The hippocampus is part of a larger temporal lobe structure called the temporal lobe.formation of the hippocampus. The formation of the hippocampus extends from the amygdala forward to the splenium of the corpus callosum behind. The formation of the hippocampus is an important part of thelimbic systemand consists of three main parts:

  • HeHippocampus(also known asright hippocampus or horn of amun),
  • Hea cogwheel,
  • Hea small room.

The elongated structures of the hippocampus lie along the longitudinal axis of the hippocampus.Brainand form the floor and part of the medial wall of the inferior horns of thelateral ventricle. The hippocampus has many functions, but is best known for its roleLearnYStore.

Key facts about the hippocampus
To herMolecular, pyramidal and polymorphic layers
FelderCA1, CA2, CA3, CA4
afferent pathwaysEntorhinal cortex, septal region, prefrontal cortex, anterior cingulate gyrus, premammary region, reticular formation
efferent pathwaysSeptal area (precommissural fornix), anterior thalamic nucleus, hypothalamic mammillary bodies (postcommissural fornix), entorhinal cortex, cingulate cortex, prefrontal cortex, contralateral hippocampus
functionsLearning, memory, aggression, anger, hormone regulation.


  1. Anatomy
  2. Internal structure
  3. a cogwheel
  4. subicular cortex
  5. Hippocampal connections: pros and cons!
    1. hippocampus input
    2. hippocampus output
  6. functions
  7. Clinical Relations
    1. Apenepilepsia temporal
    2. rabies encephalitis
    3. isquemia cerebral global
    4. alzheimer's dementia
    5. Korsakoff's Syndrome
  8. Fuentes

+ show all




(Video) 2-Minute Neuroscience: The Hippocampus

Synonym:formation of the hippocampus, hippocampus proper,Show more...

HeHippocampusIt is an elongated convex structure that projects from the floor and medial wall of theTemporary Hornof the lateral ventricle. It is about 5 cm long and widest in its anterior extent, where it flexes towards the medial aspect of the brain.correct hippocampusAlso calling 'a warning horn', meaning the horn of the ancient Egyptian god Amun.

The hippocampus extends anteriorly from the amygdala and then narrows as it runs posteriorly. Some authors divide its surface into three parts: head, body and tail.Kopfthe hippocampus contains several grooves that resemble a foot and is therefore known as thepes hippocampus(L. pes, "hit").

The ventricular surface of the hippocampus is calledreservoir. The alveolus is a thin layer of white matter formed by the axons of the pyramidal cells of the hippocampus. It is covered by the ependymal cell layer. Alveolar fibers converge at the medial border of the hippocampus to formRand des Hippocampuswhich in turn gives rise to the fornix.

area CA1


Synonym:Horn of Ammons, Horn of Ammons Area 1,Show more...

When viewed in cross-section (coronal) section, the hippocampus is divided into four designated zonesCA1-CA3(CA - Cornu ammonis). The initial division also included the fieldCA4, but today this field is considered part of the dentate gyrus.

HeCA1field, also known asSommers Sector, contains the pyramidal cells closest to the subiculum, while the other two fields CA2 and CA3 are closest to the surface. A special feature ofCA3Of note, the collaterals of the axonal processes that extend from the CA3 pyramidal cells are known as recurrent orSchaffer collateral, and these fibers actually project back into the CA1 field.

Internal structure

Hippocampal Schicht polymorph


The inner hippocampus consists ofArchikortex.Note that the archcortex has fewer cortical layers than bothNeokortex(which has six layers) and thepaleocorteza(who has four or five).

(Video) Functions and Structure of Hippocampus

The archcortex of the hippocampus consists mainly ofpyramidal cells. Pyramidal cells, like all cells, have afferent processes (dendrites) and efferent processes (axon). It should be noted that the dendrites of a pyramidal cell extend from both the apex and the base. The basicdendritesthey extend toward the surface of the lateral ventricles; while the apical dendrites extend away from the lateral ventricles and towards the dentate gyrus.

Heaxonpyramidal cells take information received from the hippocampus and send it to other brain structures; These efferent processes extend from the pyramidal cell body and travel through a structure called the Elreservoirfibrous cape adjacent to the inferior horn of the lateral ventricle and then enters the entorhinal cortex or theborder area-fornix.

The hippocampal archcortex consists of four main layers:

  • Helacunar molecular layerIt is the deepest layer of the hippocampus archcortex. This layer is mainly composed of interneurons.
  • Heradiate layerIt is formed mainly by the dendrites of pyramidal cells and stellate cells.
  • Hepyramid layerIt is the thickest and most important layer of the hippocampus. It consists of densely packed pyramidal neurons. The pyramidal layer merges with the inner pyramidal layer of the neocortex.
  • Heeast headIt is the most superficial layer of the hippocampus, located just below the alveolus. It consists primarily of basket cell interneurons and shares many structural features with the deeper layer of the neocortex.

Note that some anatomy textbooks use an older classification of the hippocampus layer, which divides the structure of the hippocampus into three layers: molecular, pyramidal, and polymorphic.

a cogwheel

a cogwheel

A change


Hea cogwheelIt is a band of cortex located between the superior aspect of the parahippocampal gyrus and
the hippocampus fimbria. The dentate gyrus gets its name from its tooth-like configuration. This configuration is created by numerous blood vessels piercing the ventricular surface of the hippocampus and the dentate gyrus.

Like the hippocampus, theirregular giroit also has several layers; but unlike the hippocampus, whose main cell is the pyramidal cell, the main cell of the dentate gyrus is thegranule she was whole. The axons of granule cells are calledjelly fibras, and synapse with pyramidal cells in theCA3hippocampal field.

The three layers that make up the dentate gyrus are (superficial to deep):

  • Hemolecular layerConsists mainly of nerve cell bodies and granules
    cellular dendrites;
  • Hegranular middle layercomposed of granular cells, the main cells of the dentate gyrus;
  • Hemultifaceted layerconsists mainly of interneurons.

subicular cortex


Hesubicular Kortexor just thea small roomIt is a transitional area between the hippocampus and the entorhinal cortex. The main distinguishing feature between the hippocampus and the subicular cortex is that thepyramidal she was whole capain the subicular cortex it is significantly thicker than in the hippocampus.

(Video) Memory and the Hippocampus

The most importantFunctionof the subiculum is to transmit information from the pyramidal cells of the hippocampus to the amylary nuclei of the hypothalamus and the anterior nuclei of the thalamus.

Do you feel a little confused? Why don't you try testing your understanding with a few?exam questions?You can use them to learn hippocampus anatomy from scratch or to identify gaps in your knowledge.

Hippocampal connections: pros and cons!

hippocampus input

Heentorrinal Kortexit is an important source of two distinct sets of afferent fibers that provide information for the formation of the hippocampus. Hesideways cross distantIt arises from the lateral entorhinal cortex and extends to the molecular layer of the hippocampus. Hehalf cross distantIt arises from the medial entorhinal cortex, extends through the white matter from the subicular cortex, and enters the alveoli of the hippocampus. Many of these fibers carry olfactory, visual, and auditory information to the hippocampus.

HeDiagonal banda Von Brocaoriginates in the septal area and functions as part of a feedback loop to the hippocampus from the septal area. The other part of this feedback loop is thepräcomissuralfornix, which allows the septal area to receive feedback from the hippocampus.

The hippocampus also receives afferent information from theprefrontal cortex,anterior cingulate gyrus, Ypre-mamillaryRegionof the brain, as well as neuronal projections of monoamine from thenetwork structure militarybrainstem(particularly the locus coeruleus, raphe nucleus and ventral tegmental area). The monoamine pathway, in particular, plays an essential role in mood regulation.

Due to these connections, the formation of the hippocampus can respond to changes in activity in the cortex and brainstem and transmit this information to the brain.hypothalamus, adding an emotional or visceral quality to these changes in brain activity.

hippocampus output

Efferent fibers from the hippocampal formation, which send signals from the hippocampus to other parts of the brain, come from thepyramidal cellshippocampus and subicular cortex. fibers of theAmygdala, located in front of the hippocampus, also move largely along with hippocampal fibers. These fiber bundles, originating in the hippocampus and amygdala, run posterodorsally along the body of the lateral ventricle around the posterior part of the ventricle.thalamus, and then anteriorly along the inferior horn of the lateral ventricle.

stria terminalis

terminal strip

The bundle of fibers coming from the hippocampus is called thefornix; is simply less thannumb body. The bundle of fibers arising from the amygdala is called the matrix.Groovenot end device, and runs parallel and ventromedially to the tail of the caudate nucleus. The fornix and stria terminalis fiber networks eventually terminate in different parts of the hypothalamus and septum.

Fornix fibers traveling rostrally toanterior commissureare your namespräcomissuralfornix. These originate from both the hippocampus and the subicular cortex and terminate in the septal region. The fibers of the precommissural fornix are organized topographically: this means that fibers near the anterior pole of the hippocampal formation project towards the lateral aspect of the lateral septal nucleus, while fibers near the posterior part of the hippocampal formation project towards the lateral aspect of the hippocampus. more medial parts of the nucleus. lateral septal nucleus.


(Video) Neurology | Limbic System Anatomy & Function

The fornice fibers that travel ventrally behind the anterior commissure are calledpostcomisuralfornix. These fibers originate in the subicular cortex and end in theanterior thalamic nucleusor in the mammary bodies of the hypothalamus. The postcommissural fornix provides parts of themidbrain, including the anterior nucleus of the thalamus, the mamillary bodies, and parts of the medial hypothalamus.

neurons of thea small roomit also sends axons to the entorhinal cortex, cingulate cortex, and regions of the prefrontal cortex. Heentorrinal Kortexsubsequently sends axons to the amygdala and parts of the temporal cortex. These interconnecting networks allow the hippocampus formation to send signals anywhere.cerebral cortex, including regions that receive and process different types of sensory information.

there is one toointerim ComponentsFornix: The purpose of this part of the fornix is ​​to connect the hippocampus to both sides of the brain. The axons that do this predominantly arise from the CA3-CA4 portions of the hippocampus and synapse in the contralateral hippocampus. It is believed that these connecting fibers may provide the pathway for thisseizure propagationfrom its primary epileptogenic focus in one hippocampus to the contralateral hippocampus, eventually allowing a secondary epileptogenic focus to form in the contralateral hippocampus.


Despite being a fairly small structure in the brain, size can be deceiving! The hippocampus performs a number of crucial functions, including the regulation of emotions, motivation, hormonal activity, autonomic activity and memory formation.

The most well-known function of the hippocampus is its role inLearnYStore. Although the exact mechanisms remain somewhat mysterious, it is believed that the hippocampus receives and consolidates information, allowing the formation of long-term memories in a process known asLong term potentiation(LTP). It also plays a role in spatial memory, allowing us to keep track of where things are and how they relate to one another. as such, it is fundamental in the formation of cognitive maps.

There are numerous reports linking human tumors, lesions, and epileptogenic activity in the hippocampus with aggressive responses ranging from mild hostility to explosive acts of violence. The role of the hippocampus in mediationAssaultYvayait seems to depend on the region of the stimulated structure: activation of the temporal pole, the region closest to the amygdala, stimulates predatory or fighting behavior; while activation of the region closest to the septal pole suppresses these pulses.

Given the numerous synaptic connections between the hypothalamus and hippocampus, it is not surprising that the hippocampus is also involved.hormones regulationand contributes to severalendocrine functions. The ventral aspects of the hippocampus were found to harbor dense regionsestradiol-Concentration of neurons, as well as high concentrations ofcorticosteronawhich inhibits these estradiol-concentrating neurons.

It has been postulated that the hippocampus may be selectively sensitive to different levels of hormones, which play a role in childbirth.feedback to thehypophysisthrough their hypothalamic connections. This is believed to occur indirectly via a synaptic relay within the septal area, as well as directly via a pathway calledmedial cortico-hypothalamic treatment. The medial corticohypothalamic tract arises near the temporal pole of the hippocampus and projects to the ventromedial hypothalamus; terminates between the suprachiasmatic and arcuate nuclei in a region that contains hypophysiotrophic hormones that mediate anterior pituitary functions.

Clinical Relations

Apenepilepsia temporal

Temporal lobe epilepsy is characterized by recurrent unprovoked seizures originating in the temporal lobe, possibly the most epileptogenic region of the brain. These seizures can beconscious focal seizures(simple partial seizures that occur without loss of consciousness) andfocal impaired consciousness(complex partial seizures with loss of consciousness), although generalized seizures may also occur. HeCA1 campoThe hippocampus, known as the summer sector, is particularly susceptible to the anoxia that can occur during temporal lobe epilepsy; this may be accompanied by excitement or aggression, anger, fear, paranoia and other emotional phenomena.

rabies encephalitis

Rabies is a negative-sense, spherical, single-stranded RNA virus that is transmitted to humans by the bite of an infected animal (usually a dog, bat, or other mammal) and causes fatal encephalitis.brain inflammation). Once the victim has been inoculated with the virus through the bite, the virus ascends to the brain through the peripheral nerves. Initial symptoms are nonspecific and include headache, fever, and general malaise. As the virus progresses, the victim experiences extremescentral nervous systemexcitabilityIt manifests as hypersensitivity to pain, violent motor reactions and convulsions. Make violent contractions of the throat muscles.To swallowdifficult and painful; Because of this, people with symptomatic rabies avoid drinking, even water, and are called "hydrophobic." These spasms in the throat are also the cause of the characteristic foam at the mouth. Eventually meningismus occurs, followed by flaccid paralysis; The alternation between mania and drowsiness leads to coma and eventually death from failure of the brain's respiratory center.

Pathognomonic histopathological findings in rabies are called round or oval eosinophilic cytoplasmic inclusions.Negri Body, which can be seen in theneurona piramidalhippocampus and Purkinje cellscerebellum.

isquemia cerebral global

Global cerebral ischemia (also known asdiffuse hypoxic/ischemic encephalopathy) is the result of a severe hypotensive episode. Among the cells of the central nervous system, neurons are the most susceptible to ischemia, although glial cells are as well. Different regions of the brain are also more vulnerable than others: the pyramidal cells in theCA1 Regionhippocampus, Purkinje cellscerebellum, and pyramidal cells in the cortex are more susceptible to global ischemia and can be damaged even when the ischemic episode is of short duration.

alzheimer's dementia

The hippocampus, along with the entorhinal cortex and amygdala, is involved in the early stages of Alzheimer's dementia and often shows severe atrophy in the later stages of the disease. In particular, the hippocampus is a site of significant formation for bothneurite plates(Collections of dystrophic neurites around a central Aβ amyloid core) andneurofibrilar plots(Intracytoplasmic bundles of filaments containing hyperphosphorylated tau protein that surround or even displace the nucleus of the neuron.)granulovakuolar Degeneration(formation of small clear cytoplasmic vacuoles, each containing an argyrophilic granule) are also seen in abundance in the hippocampus of Alzheimer's patients; ANDhirano Body(eosinophilic inclusion bodies composed primarily of actin filaments) can be seen particularly in the pyramidal cells of the hippocampus.

Korsakoff's Syndrome

Korsakoff syndrome is a disorder in which damage to the hippocampus triggers new memories (anterograde memory loss) and recover memories made before the damage (retrograde memory loss). usually associated withThiamine deficiency (vitamin B1), often associated with chronic alcohol abuse and its toxic effects on neurons, particularly those of the hippocampal formation and Papez's circuit (mamillary body, cingulate gyrus and anterior thalamic nucleus).


All content published on Kenhub is reviewed by medical and anatomical experts. The information we provide is based on scientific literature and peer-reviewed research.Kenhub does not provide medical advice.You can learn more about our content creation and review standards by reading ourContent quality guidelines.


  • Kumar, V., Abbas, A. K., Fausto, N. e Aster, J. C.:Robbins e Cotran Pathologic Basis of Disease, 8ª ed., Saunders Elsevier (2010), p. 2686, 2710-1, 2730-1
  • ODEN, J.HM, the man without memory. Psychology Today (2012), (accessed March 31, 2018).
  • Anger. Centers for Disease Control and Prevention (2011), (accessed January 6, 2018).
  • Siegel, A. and Sapru, H.N.:Essential Neuroscience, 3. Aufl., Lippincott Williams & Wilkins (2015), pág. 12, 107, 208, 444-9.
  • Sternberg, R. J. e Sternberg, K.:Cognitive Psychology, 6th ed., Wadsworth, Cengage Learning (2012), p. 48-9
  • No, D.K.temporal lobe epilepsy. Medscape (2017), (accessed March 31, 2018).

Hippocampus: Anatomy and functions: Want to know more?

Our engaging videos, interactive quizzes, in-depth articles and HD atlases are here to help you get the best results faster.

What's your favorite way to learn?


(Video) 2-Minute Neuroscience: Limbic System

"I would honestly say that Kenhub has cut my study time in half."-Keep reading.Hippocampus: anatomy and functions (2)Kim Bengochea, Universidad Regis, Denver

© Unless otherwise stated, all content, including illustrations, is the exclusive property of Kenhub GmbH and is protected by German and international copyright laws. All rights reserved.


1. Hippocampus
2. Limbic System Parts, Function and Anatomy (Amygdala, Hippocampus and Cingulate Gyrus)
(USMLE pass)
3. Anatomy of brain: Hippocampus (English)
(Ryosuke Ito)
4. ANATOMY OF THE BRAIN/A Comprehensive Guide/Anatomy and physiology
(Nursing Navigation)
5. The Brain's Hippocampus - its location and function explained by Psychology Professor Bruce Hinrichs
6. Neurosurgery written board crash course - Hippocampus
(Chen Shi)


Top Articles
Latest Posts
Article information

Author: Saturnina Altenwerth DVM

Last Updated: 02/07/2023

Views: 6229

Rating: 4.3 / 5 (44 voted)

Reviews: 83% of readers found this page helpful

Author information

Name: Saturnina Altenwerth DVM

Birthday: 1992-08-21

Address: Apt. 237 662 Haag Mills, East Verenaport, MO 57071-5493

Phone: +331850833384

Job: District Real-Estate Architect

Hobby: Skateboarding, Taxidermy, Air sports, Painting, Knife making, Letterboxing, Inline skating

Introduction: My name is Saturnina Altenwerth DVM, I am a witty, perfect, combative, beautiful, determined, fancy, determined person who loves writing and wants to share my knowledge and understanding with you.