Cardelia is visits the national aquarium in Washington D.C., and watches the seahorses swim with various fish. She begins thinking about the human brain, and remembers that one major structure, which is important in the formation of new memories, gets its name because it is shaped like a sea horse. The brain structure is a. Hippocampus. Long term memory formation gets crippled when hippocampus gets damaged. The movie 'Memento' is based on this fact.