CA fields - BrainInfo

CA fields (CAF)

The term CA fields refers to a composite substructure of the hippocampal complex of the archicortex defined on the basis of internal structure in the human ( Instausti-2012 ), macaque ( Paxinos-2009a ). rat ( Swanson-2004 ) and mouse ( Hof-2000 ). It has three parts: the CA1 field, CA2 field and CA3 field. The CA stands for Cornu ammonis, Latin for Ammon's horn, presumably so-named because bilateral dissection of the archicortex of the human produces an object shaped like the horns of a sheep, joined at the front and curving laterally, posteriorly, ventrally and back toward the front. Some authors refer to the hilus of the dentate gyrus as a fourth CA4 field ( Carpenter-1983 Paxinos-2009a ). The other two components of the hippocampal complex are the dentate gyrus and the subiculum ( Glasser-2016 ). In the human and macaque the CA fields are located between the dentate gyrus medially and the subiculum medial to the parahippocampal gyrus of the limbic lobe. In the rat and mouse they half-encircle the interbrain of the upper brainstem topologically while histologically bounded dorsally by the very small fasciola cinerea and bounded ventrally by the subiculum. Posteriorly, beyond the brainstem and extending to the caudal pole of cerebral cortex, they topologically encircle the dentate gyrus while continuing to be bounded ventrally by the subiculum ( Swanson-2004 ). Updated 27 May 2024.

Also known as: hippocampus of Carpenter, Hippocampus of Nomina Anatomica, Hippocampus of Szabo, Ammon's horn, Cornu ammonis, hippocampus major, hippocampus proper, ammon horn, CA fields, Hippocampus proprius, hippocampus of Insausti

NeuroNames ID: 182

All Names & Sources

1 of 22

Showing 22 synonym(s) - Use arrows to navigate

Showing 22 synonym(s)

Name:

нога морского коня of Sapin

Language:

Russian

Organism:

human

Source:

Sapin-1998

Citation:

Vol. 3, Moscow: Elista APP "Dzhangar", 1998

Source Title:

Anatomiia Cheloveka

Name:

hippokampus of Carpenter

Language:

Indonesian

Organism:

human

Source:

Noback-1982

Citation:

Jakarta: Penerbit Buku Kedokteran EGC, 1982

Source Title:

Anatomi Susunan Saraf Manusia, Prinsip-Prinsip Dasar Neurobiologi

Name:

аммонов рог

Language:

Russian

Organism:

human

Source:

Savel'ev-1996

Citation:

AREA XVII, Moscow, 1996.

Source Title:

Stereoskopicheskii Atlas Mozga Cheloveka

Name:

Language:

acronym

Organism:

human

Source:

Mai-1997

Citation:

San Diego: Academic Press, 1997

Source Title:

Atlas of the Human Brain

Name:

hippocampus of Carpenter

Language:

English

Organism:

human

Source:

Carpenter-1983

Citation:

Baltimore: Williams and Wilkins Co., 1983

Source Title:

Human Neuroanatomy

Name:

Hippocampus of Nomina Anatomica

Language:

Latin

Organism:

human

Source:

Nomina-1983

Citation:

Fifth Edition, Williams and Wilkins Co., Baltimore, 1983

Source Title:

Nomina Anatomica

Name:

Hippocampus of Szabo

Language:

Latin

Organism:

Macaca fascicularis

Source:

Szabo-1984

Citation:

J Comp Neurol 1984 Jan 10;222(2):265-300

Source Title:

A stereotaxic atlas of the brain of the cynomolgus monkey (Macaca fascicularis)

Name:

Ammon's horn

Language:

English

Organism:

human

Source:

Szikla-1977

Citation:

Springer-Verlag, Berlin, Heidelberg, New York, 1977

Source Title:

Angiography Of The Human Brain Cortex: Atlas of Vascular Patterns and Stereotactic Cortical Localization

Name:

Ammon's horn

Language:

English

Organism:

rat

Source:

Bowden-1997

Citation:

Source Title:

A digital Rosetta stone for primate brain terminology

Name:

Cornu ammonis

Language:

Latin

Organism:

human

Source:

Riley-1943

Citation:

Baltimore: Williams and Wilkins Co., 1943

Source Title:

An Atlas Of The Basal Ganglia, Brain Stem And Spinal Cord (Based On Myelin-Stained Material)

Name:

hippocampus major

Language:

English

Organism:

human

Source:

Crosby-1962

Citation:

New York: MacMillan, 1962

Source Title:

Correlative Anatomy of the Nervous System

Name:

hippocampus proper

Language:

English

Organism:

human

Source:

Crosby-1962

Citation:

New York: MacMillan, 1962

Source Title:

Correlative Anatomy of the Nervous System

Name:

hippocampus of Carpenter

Language:

Indonesian

Organism:

human

Source:

Noback-1982

Citation:

Jakarta: Penerbit Buku Kedokteran EGC, 1982

Source Title:

Anatomi Susunan Saraf Manusia, Prinsip-Prinsip Dasar Neurobiologi

Name:

ammon horn

Language:

English

Organism:

rat

Source:

Swanson-2004

Citation:

Third Edition, Elsevier Academic Press, Oxford, 2004

Source Title:

Brain Maps: Structure of the Rat Brain.

Name:

corne d'ammon

Language:

French

Organism:

human

Source:

Duvernoy-1992

Citation:

Springer-Verlag, Paris, 1992

Source Title:

Le cerveau humain: Surface, coupes seriees tridimensionnelles et IRM

Name:

CA fields

Language:

English

Organism:

Unspecified

Source:

NeuroNames

Citation:

University of Washington, Seattle, WA

Source Title:

NeuroNames

Name:

Hippocampus proprius

Language:

Latin

Organism:

Unspecified

Source:

NeuroNames

Citation:

University of Washington, Seattle, WA

Source Title:

NeuroNames

Name:

Language:

acronym

Organism:

rat

Source:

Swanson-2004

Citation:

Third Edition, Elsevier Academic Press, Oxford, 2004

Source Title:

Brain Maps: Structure of the Rat Brain.

Name:

Felder des Ammonshorns

Language:

German

Organism:

Unspecified

Source:

Macchi-1997

Citation:

J Neurosurg 1997 Apr;86(4):670-85

Source Title:

Toward an agreement on terminology of nuclear and subnuclear divisions of the motor thalamus

Name:

CAF

Language:

acronym

Organism:

Unspecified

Source:

NeuroNames

Citation:

University of Washington, Seattle, WA

Source Title:

NeuroNames

Name:

CAs

Language:

acronym

Organism:

Unspecified

Source:

NeuroNames

Citation:

University of Washington, Seattle, WA

Source Title:

NeuroNames

Name:

hippocampus of Insausti

Language:

English

Organism:

Unspecified

Source:

Insausti-2012

Citation:

Source Title:

Hippocampal Formation

Illustrations

Showing 5 illustration(s)

myelin stain & diagram of
all aspects in
human

labeled line drawings of
sagittal section in
Macaca fascicularis

multiple views of
3D reconstruction in
Macaca mulatta

movie of
cells in
rat

Nissl stain & diagram of
sagittal section in
mouse

Species With The Structure

Equivalent By	Human	Macaque	Rat	Mouse
Topology	Has The Structure	Has The Structure	Has The Structure	Relevant Data Not Located

1 of 8

Showing 8 record(s) - Use arrows to navigate

Showing 8 record(s)

Basis:

Topology

Has Equivalent:

Yes

Organism:

Homo sapiens (human)

Their Name:

Ammon's horn

Source:

Szikla-1977

Basis:

Topology

Has Equivalent:

Yes

Organism:

Homo sapiens (human)

Their Name:

Cornu ammonis

Source:

Riley-1943

Basis:

Topology

Has Equivalent:

Yes

Organism:

Homo sapiens (human)

Their Name:

hippocampus major

Source:

Crosby-1962

Basis:

Topology

Has Equivalent:

Yes

Organism:

Homo sapiens (human)

Their Name:

hippocampus of Carpenter

Source:

Carpenter-1983

Basis:

Topology

Has Equivalent:

Yes

Organism:

Homo sapiens (human)

Their Name:

Hippocampus of Nomina Anatomica

Source:

Nomina-1983

Basis:

Topology

Has Equivalent:

Yes

Organism:

Homo sapiens (human)

Their Name:

hippocampus proper

Source:

Crosby-1962

Basis:

Topology

Has Equivalent:

Yes

Organism:

Macaca fascicularis (Macaca fascicularis)

Their Name:

Hippocampus of Szabo

Source:

Szabo-1984

Basis:

Topology

Has Equivalent:

Yes

Organism:

Rattus (rat)

Their Name:

Ammon's horn

Source:

Swanson-2004

Models Where It Appears

Structural CNS Model - Macaque

Brain structures of the macaque are illustrated in BrainInfo’s NeuroMaps macaque brain atlas. Structures are grouped by proximity in a hierarchy corresponding to the central nervous system hierarchy of NeuroNames ( Bowden-1995 Martin-2000 ). Structures in the NeuroMaps atlas are based on the segmentation of an MRI of the brain of a 3-year old male rhesus macaque (Macaca mulatta). The atlas is most useful for targeting structures for implantating electrodes and chemtrodes. Updated 29 Oct 2025.

brain

forebrain

endbrain

cerebral white matter

substantia innominata

basal nucleus (basal forebrain nucleus)

islands of Calleja

nucleus accumbens

anterior olfactory nucleus

olfactory tubercle

main olfactory bulb (olfactory bulb)

olfactory peduncle (olfactory tract)

telodiencephalic fissure

midbrain

hindbrain

choroidal fissure

Functional CNS Model - Rat

The Functional CNS Model - Rat (FMrat) ( Swanson-2004) is one of three hierarchical models representing the internal organization of the central nervous system (CNS). The others are the Structural CNS Model - Human (SThmn) and the Functional CNS Model - Human (FMhmn). The FMrat model represents the basic organization of the mouse ( Hof-2000 AMBA-2024 ) and, presumably, other rodents. Functional CNS models differ from structural models in that structures are defined and named by connectivity rather than by proximity to other structures at the same level. Functional models are more useful for representing longitudinal components of are grouped based on information drawn from multiple neuroscientific disciplines. such as connections, neurochemical characteristics, and role in physiogical and behavioral processes. While the Functional Model was developed primarily for an atlas of the rat brain ( Swanson-2004 ), the hierarchical organization of structures is for the most part applicable to the human, macaque, mouse and other mammalian brains as well. Structures at lower levels of the Functional CNS hierarchy are largely the same as in the Classical and Developmental Models, i.e., they were originally identified by stains for gray matter (Nissl substance) and white matter (myelin). At the next higher level they are grouped into basic connectional and functional systems of the CNS, such as the subcortical sensory systems, the brainstem motor system and the behavioral state system. At the highest levels CNS structures are grouped on the basis of dissection and embryologic precursors into cerebrum ( cerebral cortex and cerebral nuclei ), cerebellum, and cerebrospinal trunk.