2.15. Tail suspension test

The tail suspension test, which was developed by Steru et al,³⁷ was performed to assess depression‐related behavior. Each mouse was suspended 30 cm above the floor by the tail in a white plastic chamber (44 cm height × 49 cm length × 32 cm width, inside dimensions; O'Hara & Co.) with a video camera mounted on the wall (O'Hara & Co.). The behavior was recorded for 10 minutes. Images were captured at two frames per second through the video camera. Similar to the Porsolt forced swim test, the immobility of each mouse was judged according to a certain threshold using ImagePS software.