It contains two main interlocking parts: Ammon's horn and the dentate gyrus.

Ammon's horn, a part of the hippocampus (a major component of the human brain)

The CHRNA7 gene is primarily expressed in the posterior amygdalar nucleus and the field CA3 of Ammon's horn in the mouse, and in the mammillary body in humans.

Negri bodies are eosinophilic, sharply outlined, pathognomonic inclusion bodies (2-10 m in diameter) found in the cytoplasm of certain nerve cells containing the virus of rabies, especially in Ammon's horn of the hippocampus.