Sociability and Social Novelty Preference Tests Using a U-shaped Two-choice Field.

We developed sociability tests based on use of a U-shaped two-choice field to read out behavioral states of sociability in rodents. The U-shaped two-choice field is a modified open field that is partially partitioned with a wall projecting to the central point, resulting in two symmetrical rectangular fields, each containing closed and open square zones that together form a 'U-shaped field'. The U-shaped two-choice field can be used to measure animal's behavioral responses to two contrasting or similar options, such as (i) a social target versus an inanimate object, (ii) a new stranger versus an earlier stranger, and (iii) a novel animal (a non-mate) versus a cage-mate (a familiar animal). We describe detailed procedures for sociability tests for the above three behavioral test paradigms based on the U-shaped two-choice field.