Morris Water Maze (MWM)
By training mice to find a hidden platform submerged in water, a MWM paradigm was used to evaluate the cognitive abilities of mice. As described previously (Vorhees & Williams, 2006), by adding edible titanium dioxide to opaque water (35 °C) within a circular pool with a diameter of 120 cm and wall height of 50 cm, the mice were allowed to swim in a circular pool. An 8 cm diameter platform was hidden 1 cm below the surface of the water. Mice were trained to find the hidden platform by markers around the pool within 60 s. If the mouse failed to find the platform within 60 s, it was guided to the platform and requested to stay there for 30 s. Three trials were conducted for each mouse, starting at different points in the afternoon each day for six consecutive days in order to locate the platform beneath the water’s surface. A probe test was administered to the mice following a training period of six days. For the probe test, the mice were left to swim without the platform for 60 s. EthoVision video tracking system (Noldus Information Technology, Netherlands) was used to analyze the escape latency, swim speed, distance traveled, time spent within the target quadrant, and crossing times of the platform during the entire test.