ZH-KJ Scene Scene fear fear experimental system Experimental System (FCS) for small rodents (rats and mice) environment-related conditions Experimental Study on fear. When fear rodents exhibit unique stationary state (immobility), in which case the animals tend to remain stationary defensive posture. Antidepressants and anti-central stimulant drugs can significantly shorten the duration of a stationary state. During the experiment, subjects were given a voice signal (conditioned stimulus), then give an electric shock (unconditioned) stimulus. The training is called conditional training, after training the experimental animals or environmental sound signal contact experiments. Rodents for the same signal will sound at the appropriate environment and make different environmental conditions generally obvious fear reaction, such as stationary. This test can be immediately or after a few days of training can provide information after short-term and long-term memory in the signal under influence.