Figure 12. The Morris water maze assesses spatial learning and memory in mice.

Mice are dropped at selected locations (B) in a specific order and must locate the submerged platform on which a visible cue is placed (A). In later trials, the visible cue is removed, and the water is made opaque by a non-toxic, non-abrasive agent such as powdered milk or chalk to hide the platform. For analysis, the pool is divided into four quadrants; for example, (C) is one quadrant. Inset: close-up of the visible platform in the Morris water maze. Here, it is clear that the platform is submerged. In later trials, the platform becomes hidden when the visible cue is removed.