Ammon's horn

n. Ammon's horn (also known as cornu ammonis) represents one division of the hippocampal formation with the dentate gyrus and the subiculum. It is a three-layered archicortical structure divided into four different fields, named CA1, CA2, CA3, and CA4. CA4 is also called hilus and indeed is considered part of the dentate gyrus. CA1- CA3 fields are frequently referred to as the hippocampus proper. Ammon’s horns are situated in the medial temporal lobe at the level of the floor of the inferior horn of the lateral ventricles. The hippocampus proper is thought responsible for the acquisition of consciously accessible, declarative memory. Damage in these structures is associated with a severe amnesia without confabulation and confusion. The left hippocampus seems more involved in semantic memory, whereas the right one seems more directly related to spatial memory.  -AA

►See also MEMORY