Morris Water Maze

The Morris water maze (MWM) is one of most common behavioral tests of spatial learning for rodents (Vorhees and Williams, 2006). The MWM was performed based on a previously published method with some modifications (Xu et al., 2018). Briefly, each mouse was placed in a round plastic tub with a diameter of 108 cm filled with white-painted water at the temperature of 22–23°C to locate and escape onto a submerged platform. Four visible cues were placed at different points around the tub. Each animal was placed at random locations distal to the platform and allowed to swim to find the hidden platform. If the animal failed to locate the platform within 1 min, it would be gently guided to and remained on the platform for 10 s. Each animal was then placed in a warm cage with a heating pad underneath. There were approximately 5 min in between trials. Each mouse was given four daily trials for five consecutive days. Animal movements were recorded and analyzed using EthoVision XT 8.0 video tracking software (Noldus Information Technology, Leesburg, VA, United States).