Although the hippocampus seems to be related to memory, experiments that destroy the human hippocampus are ethically difficult, so experiments using rats and other animals have flourished. I explain the important experiments: Morris Water Maze.
The Morris Water Maze is an experiment that drops rats in opaque water and makes the rat finds a scaffold. Neuroscientist Richard G. Morris invented it. First, prepare a columnar aquarium. Prepare a scaffold with a diameter of 10 cm in this. Since the scaffold is 1 cm below the surface of the water and the water is opaque, the rat does not know where the scaffold is. (*6)
We drop the rat in this aquarium. The rat does not want to drown, so it swims and find a scaffold. If we drop the same rat into the aquarium many times, the rat learns the place of the scaffold and quickly heads to the scaffold. In contrast, rats with broken the hippocampas failed to learn the location of the scaffold. (*7)
Footnotes:
- *6: The size of the aquarium is 150 to 200 cm in diameter and 50 cm in depth. Around the aquarium, there is a landmark for grasping the place. See Morris water maze for more detail.
- *7: To break hippocampus fanctions, we injected NDMA receptor blocking drug into the hippocampus.