Behavioral Tasks for Examining Identity Recognition In Mice

Social animals, like rodents, are able to recognize and differentiate between the identity of familiar individuals. Recognizing the identity of familiar individuals is important for developing social structures such as hierarchy, kinship, and family. However, mechanisms underlying the recognition of social identity remain unclear. Most rodent studies of social recognition are based on the propensity of rodents to interact with a novel social target, a phenomenon known as social novelty. However, behavioral tasks for examining social novelty cannot reveal the recognition of familiar conspecifics based on their identities. Presented here are behavioral tasks allowing for the examination of identity recognition in C57BL/6 mice by associating two familiar mice with or without a valenced experience. Subjects had interactions with two mice either without (neutral) or with a valenced experience (negative or positive) and became familiar with these mice. The negatively valenced mouse was associated with shocks, while the positively valenced mouse was associated with a food reward. Following training, the recognition of the identity of these familiar mice can be revealed in a social discrimination test, which is represented as the preference for the positively valenced mouse and avoidance of the negatively valenced mouse compared to the neutral mouse. Behavioral tasks for identity recognition could be useful in probing social memory mechanisms and the pathophysiology of disorders with impaired social cognition, such as autism spectrum disorder or schizophrenia.