FIGURE 2.

Semi-naturalistic environments allow the study of inter-individual variability with a social context. (A) Souris-City environment includes a large and complex living space, in which mice live together and can express sophisticated social and non-social behaviors, and an individual test zone: a T-maze delivering different drinks on each side (e.g., water or sucrose). In the T-maze, mice (inbred male C57BL/6J strain) can perform a cognitive decision-making task spontaneously and isolated from their conspecifics. The various detectors present in the environment allow to follow each individual’s behavior and estimate spontaneous individual traits. These are derived from both the general behavior expressed within the social group in the main environment, and the behavior and cognitive performance in the individual test zone. (B) Stable and distinctive patterns of choice strategy in the T-maze consistently emerged in independent experiments with, in particular, individuals tracking sucrose (right panel) and individuals constantly choosing the same side independently from the sucrose position (left panel). (C) Strikingly, when modifying the social environment by mixing mice from different Souris-City experiments but with similar behaviors, we observed a fast re-adaptation of individual traits, suggesting a social component to this individuation process (Torquet et al., 2018).