Hippocampus: Difference between revisions

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'''Hippocampus''' is a major component of the [[brain]] in humans and other vertebrates. It belongs to the [[limbic system]] and plays important roles in the consolidation of information from [[short-term memory]] to [[long-term memory]], and in spatial memory that enables navigation.
{{short description|Part of the brain involved in memory and navigation}}
{{Use dmy dates|date=October 2023}}


== Anatomy ==
==Hippocampus==
The hippocampus is located in the [[medial temporal lobe]] of the brain, underneath the cortical surface. It contains two main interlocking parts: Ammon's horn and the [[dentate gyrus]].
The '''hippocampus''' is a major component of the [[brain]] of humans and other [[vertebrates]]. It belongs to the [[limbic system]] and plays important roles in the consolidation of information from [[short-term memory]] to [[long-term memory]], and in [[spatial memory]] that enables navigation.


=== Ammon's Horn ===
[[File:Gray739-emphasizing-hippocampus.png|thumb|right|Diagram of the human brain with the hippocampus highlighted.]]
Ammon's horn, also known as the [[cornu ammonis]], is divided into four fields: CA1, CA2, CA3, and CA4. Each field has different properties and connections, which contribute to the functional diversity of the hippocampus.


=== Dentate Gyrus ===
==Anatomy==
The dentate gyrus is a part of the hippocampal formation. It is thought to contribute to the formation of new episodic memories, the spontaneous exploration of novel environments, and other functions.
The hippocampus is located in the [[medial temporal lobe]] of the brain, underneath the cortical surface. It has a distinctive curved shape that has been likened to a [[seahorse]], which is reflected in its name derived from the Greek words "hippos" (horse) and "kampos" (sea monster).


== Function ==
[[File:Hippocampus_and_seahorse_cropped.JPG|thumb|left|The hippocampus is named for its resemblance to a seahorse.]]
The hippocampus has several functions in the brain, including:


* '''Memory Formation:''' The hippocampus is critical for the formation of new memories. Damage to the hippocampus can result in severe memory impairment.
The hippocampus consists of two main interlocking parts: the [[Ammon's horn]] and the [[dentate gyrus]]. The Ammon's horn is further divided into subfields CA1, CA2, CA3, and CA4, each with distinct cellular compositions and functions.


* '''Spatial Navigation:''' The hippocampus contains "place cells" that fire when an individual is in a specific location. This is thought to contribute to an individual's ability to navigate through space.
==Function==
The primary function of the hippocampus is in the formation of new memories and is also associated with learning and emotions. It is particularly important for [[declarative memory]], which involves facts and events, and [[spatial memory]], which involves the ability to navigate and remember locations.


* '''Stress Regulation:''' The hippocampus is involved in the regulation of the body's response to stress. It is particularly sensitive to stress hormones like cortisol.
[[File:Blausen_0614_LimbicSystem.png|thumb|right|The hippocampus is part of the limbic system, shown here in a diagram of the human brain.]]


== Clinical Significance ==
===Memory===
Damage to the hippocampus can result in memory loss and difficulties with spatial navigation. Conditions such as [[Alzheimer's disease]] and [[epilepsy]] often involve hippocampal damage and dysfunction.
The hippocampus is crucial for the formation of new memories. Damage to the hippocampus can result in [[anterograde amnesia]], where the ability to form new memories is impaired, while older memories remain intact.


== See Also ==
===Spatial Navigation===
* [[Neuroanatomy]]
The hippocampus is involved in spatial navigation and memory. It helps in the formation of [[cognitive maps]], which are mental representations of physical locations.
 
[[File:Rats_and_cognitive_maps_and_maze.png|thumb|left|Rats use their hippocampus to navigate mazes, forming cognitive maps.]]
 
==Pathology==
Damage to the hippocampus can result from various conditions, including [[Alzheimer's disease]], [[hypoxia]], [[encephalitis]], or [[temporal lobe epilepsy]]. Such damage can lead to memory deficits and difficulties in spatial navigation.
 
==Research==
Research on the hippocampus has been extensive, with studies ranging from its role in memory and learning to its involvement in [[neurogenesis]] and [[plasticity]]. The hippocampus is one of the few regions of the brain where new neurons are generated throughout life.
 
[[File:Sobo_1909_639.png|thumb|right|Early anatomical drawing of the hippocampus.]]
 
==Comparative Anatomy==
The structure and function of the hippocampus are conserved across many species, including [[mammals]], [[birds]], and [[reptiles]]. In [[macaques]], the hippocampus is similarly involved in memory and spatial navigation.
 
[[File:Brainmaps-macaque-hippocampus.jpg|thumb|left|Hippocampus in a macaque brain.]]
 
==Historical Perspective==
The study of the hippocampus has a rich history, with significant contributions from scientists such as [[Santiago Ramón y Cajal]], who provided detailed drawings of its structure.
 
[[File:CajalHippocampus_(modified).png|thumb|right|Drawing of the hippocampus by Santiago Ramón y Cajal.]]
 
==Neuroanatomy==
The hippocampus is part of the [[archicortex]], one of the oldest parts of the brain in evolutionary terms. It is connected to other parts of the brain through the [[fornix]] and receives input from the [[entorhinal cortex]].
 
[[File:Hippocampus_coronal_section176157.fig.004.jpg|thumb|left|Coronal section of the hippocampus.]]
 
==Related pages==
* [[Limbic system]]
* [[Memory]]
* [[Memory]]
* [[Alzheimer's disease]]
* [[Spatial memory]]
* [[Epilepsy]]
* [[Neurogenesis]]
* [[Cognitive map]]


== References ==
[[Category:Brain]]
<references />
 
[[Category:Neuroanatomy]]
[[Category:Memory]]
[[Category:Memory]]
[[Category:Brain]]
[[Category:Limbic system]]
 
{{stub}}
{{dictionary-stub1}}
<gallery>
File:Hippocampus_and_seahorse_cropped.JPG|Hippocampus
File:Blausen_0614_LimbicSystem.png|Hippocampus
File:Sobo_1909_639.png|Hippocampus
File:Brainmaps-macaque-hippocampus.jpg|Hippocampus
File:Hippocampus_coronal_section176157.fig.004.jpg|Hippocampus
File:Rats_and_cognitive_maps_and_maze.png|Hippocampus
File:Place_Cell_Spiking_Activity_Example.png|Hippocampus
File:Rat-hippocampal-activity-modes.png|Hippocampus
File:eeg_theta.svg|Hippocampus
File:Epilepsy-_right_hippocampal_seizure_onset.png|Hippocampus
File:Epilepsy-left_hippocampal_seizure_onset.png|Hippocampus
File:Golgi_Hippocampus.jpg|Hippocampus
</gallery>

Latest revision as of 14:15, 21 February 2025

Part of the brain involved in memory and navigation



Hippocampus[edit]

The hippocampus is a major component of the brain of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation.

Diagram of the human brain with the hippocampus highlighted.

Anatomy[edit]

The hippocampus is located in the medial temporal lobe of the brain, underneath the cortical surface. It has a distinctive curved shape that has been likened to a seahorse, which is reflected in its name derived from the Greek words "hippos" (horse) and "kampos" (sea monster).

The hippocampus is named for its resemblance to a seahorse.

The hippocampus consists of two main interlocking parts: the Ammon's horn and the dentate gyrus. The Ammon's horn is further divided into subfields CA1, CA2, CA3, and CA4, each with distinct cellular compositions and functions.

Function[edit]

The primary function of the hippocampus is in the formation of new memories and is also associated with learning and emotions. It is particularly important for declarative memory, which involves facts and events, and spatial memory, which involves the ability to navigate and remember locations.

The hippocampus is part of the limbic system, shown here in a diagram of the human brain.

Memory[edit]

The hippocampus is crucial for the formation of new memories. Damage to the hippocampus can result in anterograde amnesia, where the ability to form new memories is impaired, while older memories remain intact.

Spatial Navigation[edit]

The hippocampus is involved in spatial navigation and memory. It helps in the formation of cognitive maps, which are mental representations of physical locations.

Rats use their hippocampus to navigate mazes, forming cognitive maps.

Pathology[edit]

Damage to the hippocampus can result from various conditions, including Alzheimer's disease, hypoxia, encephalitis, or temporal lobe epilepsy. Such damage can lead to memory deficits and difficulties in spatial navigation.

Research[edit]

Research on the hippocampus has been extensive, with studies ranging from its role in memory and learning to its involvement in neurogenesis and plasticity. The hippocampus is one of the few regions of the brain where new neurons are generated throughout life.

Early anatomical drawing of the hippocampus.

Comparative Anatomy[edit]

The structure and function of the hippocampus are conserved across many species, including mammals, birds, and reptiles. In macaques, the hippocampus is similarly involved in memory and spatial navigation.

Hippocampus in a macaque brain.

Historical Perspective[edit]

The study of the hippocampus has a rich history, with significant contributions from scientists such as Santiago Ramón y Cajal, who provided detailed drawings of its structure.

Drawing of the hippocampus by Santiago Ramón y Cajal.

Neuroanatomy[edit]

The hippocampus is part of the archicortex, one of the oldest parts of the brain in evolutionary terms. It is connected to other parts of the brain through the fornix and receives input from the entorhinal cortex.

Coronal section of the hippocampus.

Related pages[edit]