Within the same species, all animals have their own behavioural characteristics. Some individuals are more aggressive than others or take more risk. This is the definition of individuality. The mechanisms underlying these individual differences are poorly understood.

Researchers from IBPS¹ and the Institute for Longevity have shown that the social environment of mice is an important determinant of an individual's behavioural repertoire and modulates the activity level of neural populations². To reach this conclusion, they developed a complex environment where mice live in groups while performing cognitive tests isolated from their congeners. These experiments have shown the emergence of stable distinctive traits in a group of genetically identical individuals, despite a single environment for all animals. When individuals with the same profile are selected and grouped together in the same environment, differences in behaviour and neural activities reappear.

These results suggest that, far from being fixed, what defines an individual is modified by the social structure in which animals evolve. Social interactions are, therefore, an important factor in adapting individual traits and a driving force for generating diversity.

The next step: the social context, by acting on the nervous circuits involved in decision-making, could also have an impact on the vulnerabilities of each individual to pathologies such as addiction.

These results were published in Nature Communication in August 2018 and were the subject of a press release from the CNRS and Inserm.

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¹ Team Neurophysiology and Behavior (UMR 8246) and Team Brain Developmen, Repair Ageing(UMR 8256)

² Torquet, N., Marti, F., Campart, C., Tolu, S., Nguyen, C., Oberto, V., Benallaoua, M., Naudé, J., Didienne, S., Debray, N., et al. (2018). Social interactions impact on the dopaminergic system and drive individuality. Nat. Commun. doi:10.1038/s41467-018-05526-5.