Novelty suppressed feeding test (NSFT)

In light of previously described (24), rats were fasting for 24 h before the test. When the experiment start, rats were placed in a test chamber (50 × 50 × 40 cm) covered with a layer of 2 cm thick wood chips from any of four corners. Food pellets were weighted and then were placed in the center of test chamber. The time from rats entering into chamber to pick up food with forelimb was defined as latency, which is a key index to reflect the degree of depression. To eliminate the influence of differences in rat appetite on the latency to feed, the rat was reintroduced to their home cage and total food intake in 10 min was recorded.