Pole Test

The pole test was performed as previously described with minor modifications (37, 38). The mouse was placed head-upward on a small platform on top of a vertical rough-surfaced pole (diameter 10 mm; height 50 cm) and the time until the mouse descended to the floor (locomotor activity time: T_LA) was recorded with a maximum duration of 120 s. Even if the mouse descended part of the way and fell the rest of the way, the behavior was scored until it reached to the floor. When the mouse did not turn downward and instead dropped from the pole, T_LA was considered as 120 s because of maximal severity. The pole test was performed on 3 different days (day 18, 25, and 32), with 5 consecutive trials per mouse.