CA fields (CAF)

The term CA fields refers to a composite substructure of the hippocampal complex of the hippocampus 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 hippocampus 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 diencephalon 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

Showing 22 synonym(s)

Language
Name
Source
English
ammon horn
English
Ammon's horn
English
Ammon's horn
English
CA fields
English
hippocampus major
English
hippocampus of Carpenter
English
hippocampus of Insausti
English
hippocampus proper
Species With The Structure
Equivalent By Human Macaque Rat Mouse
Topology Has The Structure Has The Structure Has The Structure Relevant Data Not Located

Showing 8 record(s)

Basis
Has Equivalent
Organism
Their Name
Source
Topology
Yes
Ammon's horn
Topology
Yes
Cornu ammonis
Topology
Yes
hippocampus major
Topology
Yes
hippocampus of Carpenter
Topology
Yes
Hippocampus of Nomina Anatomica
Topology
Yes
hippocampus proper
Topology
Yes
Hippocampus of Szabo
Topology
Yes
Ammon's horn
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.

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.