2. A genus of small fish having a head shaped somewhat like that of a horse; the sea-horse.
3. An area buried deep in the forebrain that helps regulate emotion and memory.
Functionally, the hippocampus is part of the olfactory cortex, that part of the cerebral cortex essential to the sense of smell. Certain antidepressants (such as fluoxetine, or Prozac) influence the birth of new neurons in the hippocampus.
The hippocampus is so-called because its shape suggests that of a seahorse. From the Greek hippos, "horse" plus kampos, "a sea monster".
2. A narrow band of fibrous white matter (myelinated axons), which form the fornix (various arched structures), situated on the medial ventricular surface of the hippocampus (area buried deep in the forebrain that helps regulate emotion and memory).