​​What is the hippocampus?

The hippocampus (named after its resemblance to the seahorse, from the Greekἱππόκαμπος, "seahorse" from ἵππος hippos, "horse" and κάμπος kampos, "sea-monster") is a major component of the brains of humans and other vertebrates. It's the elongated ridges on the floor of each lateral ventricle of the brain, thought to be the centre of emotion, memory, and the autonomic nervous system.
Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation.