2.15 Morris water maze
The Morris water maze (MWM) was performed as described in our previous
study with some modifications (Fan et al., 2019). Briefly, mice at the
age of 10 months old were trained for 2 days and subsequently tested for
5 days using MWM. The mice were trained 3 times a day for 2 days to find
the visible platform (5 cm dia.) above the water, and then were tested 3
trails a day for 5 days to find the hidden platform (1 cm below the
water surface). A total of 1 min was given for the mice to find the
platform. The escape latency and the path length during MWM were
recorded using SMART 3.0 software to evaluate their spatial learning
scores. For the probe trail test, 24 h after the last trail of the
hidden platform test, the platform was removed, and the number of times
that the mice crossed the platform region during 1 min was recorded by
the SMART 3.0 software.