Hippocampus

The hippocampus is a section of the brain located below the cerebral cortex. It is a part of the limbic system and plays a part in memory.

The name derives from the fact that its curved shape resembles that of a sea horse (Greek: hippocampus).

There is substantial evidence (from animal studies and from patients with brain injury) that the hippocampus is crucial in the conversion of short term memory into long memory, though it is not yet clear how this occurs. Individuals whose hippocampus becomes damaged (for instance, those with Korsakoff's syndrome), whilst retaining the ability to access long-term memories from before their injury, become unable to form new ones. They can, however, learn new skills (such as playing a musical instrument) but will be totally unable to remember how they gained those skills.

There is also evidence, that the hippocampus is involved in storing unique information, as for example locations. Without a fully functional hippocampus a person may no more be able remember the places he/she has been to and how to get there. London's cab drivers on the other hand, who are required to learn a large number of places and locations, are well known for developing a big hippocampus. The hippocampus seems to grow when storing more information, as many regions of the brain do. (Although nobody knows whether these cab drivers have trained their hippocampus to this extent, or just a person with large well-developed dorsal hippocampus have more chances to become a taxi-driver.)

It is because it attacks the hippocampus first that Alzheimer's disease is first discovered by the patient's memory loss.

See also: LTP, LTD, subiculum, dentate gyrus

In Greek mythology, the hippocampus (horse-like sea monster") was a mythical monster, half-horse, half-sea-monster. One of them pulled Poseidon's chariot. It looked like a horse with the rear part resembling a fish or dolphin.

In biology, hippocampus is a genus of fish, the sea-horses, that swim upright with a gripping tail and a horse-like head. See hippocampus (fish)

---

Hippocampus (fish)

(From Wikipedia, the free Encyclopedia)

photo by NOAA

A hippocampus (or seahorse) is a genus of fish (family Syngnathidae) found in temperate and tropical waters all over the world.

Seahorses range in size from 16 mm (the recently discovered species [1]) to 35 cm. They are notable for being one of only a few species where the males get pregnant. A seahorse pregnancy lasts approximately two to three weeks. Seahorses are also unusual among fishes for being monogamous.

There are approximately 35 known species of seahorse including:

• H. abdominalis (pot-bellied seahorse) which is found off the coast of New Zealand, and south and east Australia
• H. algiricus (West African Seahorse)
• H. angustus (Narrow Bellied Seahorse)
• H. barbouri (Barbour's seahorse or Zebra-snout seahorse)
• H. bargibanti (Pygmy Seahorse) which is found in the area of New Caledonia
• H. borboniensis (Réunion Seahorse)
• H. breviceps (Short Snouted Seahorse) which is found off the coast of south and east Australia
• H. camelopardalis (Giraffe Seahorse)
• H. capensis (Knysna Seahorse)
• H. comes (Tiger Tail Seahorse) which is found in the Far East
• H. coronatus (Crowned Seahorse)
• H. erectus (Lined Seahorse) which is found off the east coast of the Americas, between Nova Scotia and Uruguay
• H. fisheri (Fisher's Seahorse)
• H. fuscus (Sea Pony) which is found in the Indian Ocean
• H. guttulatus (Speckled Seahorse)
• H. hippocampus (European Seahorse) which is found in the Mediterranean Sea and Atlantic Sea
• H. histrix (Thorny Seahorse) which is found in the Indian Ocean, Persian Gulf, Red Sea, and the Far East
• H. ingens (Pacific Seahorse) which is found off the Pacific coast coast of North, Central and South America)
• H. jayakari (Jayakar's Seahorse)
• H. kelloggi (Great Seahorse)
• H. kuda (Spotted Seahorse)
• H. lichtensteinii (Lichtenstein's Seahorse)
• H. minotaur (Bullneck Seahorse)
• H. mohnikei (Japanese Seahorse)
• H. procerus (Hippocampus procerus)
• H. reidi (Brazilian Seahorse) which is found in the Caribbean in coral reefs
• H. sindonis (Shiho's seahorse)
• H. spinosissimus (Hedgehog Seahorse)
• H. subelongatus (Tigersnout Seahorse or West Australian Seahorse)
• H. trimaculatus (Three-Spot Seahorse)
• H. tuberculatus (Knobby Seahorse)
• H. whitei (White's Seahorse)which is found off the coast of east Australia
• H. zebra (Zebra Seahorse)
• H. zosterae (Dwarf Seahorse) which is found in the Gulf of Mexico and the Caribbean)

Seahorse populations have been endangered in recent years by overfishing. The seahorse is used in traditional Chinese medicine. As many as 20 million seahorses a year may be caught and sold for this purpose. [1]

External Links

• seahorse.org - Keeping and Breeding Seahorses in the home aquarium.
• Shedd Aquarium: Seahorse Symphony Citat: "...Seahorses, pipefishes and seadragons also share another unusual trait. The male becomes pregnant!..."
• Shedd Aquarium: Dwarf Seahorse (Sea Pony), Lined Seahorse, Potbelly Seahorse, Speckled Seahorse, Spiny Seahorse
• Mulhuse, France, by Thierry Schmidt, About Seahorses
• Seahorses Citat: "...Both large seahorses and the pygmies can be a bit difficult to keep alive but not impossible...don't give them turbulent water!...". From this main page Welcome to Jeff Pfohl's Reef Page > Marine and Reef Aquaria.
• Aquariumsite.org: Saltwater aquarium / Seahorses
• Les liens des Hippocampes / Hippocampus links French page with english links
• Yahooligans: Seahorses, Short-snouted Seahorse
• Project Seahorse