The sucrose preference test (SPT) is a test commonly used to evaluate the emotional state and pleasure of mice or rats. In the experiment, animals were provided with two drinking water options, one was water containing sucrose and the other was ordinary water. The animal's response to pleasurable stimuli can be assessed by recording its intake of sucrose-containing water. Reduced preference for sucrose water may suggest changes in the animal's emotional state, such as depression. SPT is widely used to study antidepressant drug effects, chronic stress models, and affective behavioral assessment.