2.2.5. Morris Water Maze Task

Morris water maze tasks were performed as previously described [18]. Briefly, the mice were tested in a black circular pool with a diameter of 180 cm and a height of 60 cm that was theoretically divided into four equal quadrants. The 13 cm diameter escape platform, which was submersed 1 cm below the water surface, was put in the center of one quadrant. In each training trial, the mice explored freely in the maze for up to 90 s. Those who did not reach the escape platform within 90 s were gently led to it by the experimenter. After each trial, the mouse was left on the escape platform for another 20 s. The training was conducted 4 times a day for 4 consecutive days. Between each trial, the interval was more than 30 min. Twenty-four hours after the last training, a probe trial was conducted for 90 s without the escape platform. The swimming speed, the first latency to the platform (target) zone, and the distance traveled until the first entry into the target zone were measured to evaluate spatial memory.