<P> Since different neuronal cell types are neatly organized into layers in the hippocampus, it has frequently been used as a model system for studying neurophysiology . The form of neural plasticity known as long - term potentiation (LTP) was initially discovered to occur in the hippocampus and has often been studied in this structure . LTP is widely believed to be one of the main neural mechanisms by which memories are stored in the brain . </P> <P> The earliest description of the ridge running along the floor of the temporal horn of the lateral ventricle comes from the Venetian anatomist Julius Caesar Aranzi (1587), who likened it first to a silkworm and then to a seahorse (Latin: hippocampus from Greek: ἵππος, "horse" and κάμπος, "sea monster"). The German anatomist Duvernoy (1729), the first to illustrate the structure, also wavered between "seahorse" and "silkworm ." "Ram's horn" was proposed by the Danish anatomist Jacob Winsløw in 1732; and a decade later his fellow Parisian, the surgeon de Garengeot, used "cornu Ammonis"--horn of (the ancient Egyptian god) Amun, who was often represented as having a ram's head . This has survived in abbreviated form as CA in naming the subfields of the hippocampus . Another reference appeared with the term pes hippocampi, which may date back to Diemerbroeck in 1672, introducing a comparison with the shape of the folded back forelimbs and webbed feet of the mythological hippocampus, a sea monster with a horse's forequarters and a fish's tail . The hippocampus was then described as pes hippocampi major, with an adjacent bulge in the occipital horn, described as the pes hippocampi minor and later renamed as the calcar avis . The renaming of the hippocampus as hippocampus major, and the calcar avis as hippocampus minor, has been attributed to Félix Vicq - d'Azyr systematising nomenclature of parts of the brain in 1786 . Mayer mistakenly used the term hippopotamus in 1779, and was followed by some other authors until Karl Friedrich Burdach resolved this error in 1829 . In 1861 the hippocampus minor became the centre of a dispute over human evolution between Thomas Henry Huxley and Richard Owen, satirised as the Great Hippocampus Question . The term hippocampus minor fell from use in anatomy textbooks, and was officially removed in the Nomina Anatomica of 1895 . Today, the structure is just called the hippocampus, with the term Cornu Ammonis surviving in the names of the hippocampal subfields CA1--CA4 . </P> <P> The term limbic system was introduced in 1952 by Paul MacLean to describe the set of structures that line the edge of the cortex (Latin limbus meaning border): These include the hippocampus, cingulate cortex, olfactory cortex, and amygdala . Paul MacLean later suggested that the limbic structures comprise the neural basis of emotion . The hippocampus is anatomically connected to parts of the brain that are involved with emotional behavior--the septum, the hypothalamic mammillary body, and the anterior nuclear complex in the thalamus, and is generally accepted to be part of the limbic system . </P> <P> The hippocampus can be seen as a ridge of gray matter tissue, elevating from the floor of each lateral ventricle in the region of the inferior or temporal horn . This ridge can also be seen as an inward fold of the archicortex into the medial temporal lobe . The hippocampus can only be seen in dissections as it is concealed by the parahippocampal gyrus . The cortex thins from six layers to the three or four layers that make up the hippocampus . </P>

What does the hippocampus do in your brain