Responses to nicotine among mice in a micro-society can be predicted by their individualistic reward seeking strategy, according to a study published October 24 in the open access journal PLOS Biology by Philippe Faure, from PSL Research University, France, and colleagues.
Nicotine use is quite variable; and personality traits have been associated with nicotine use. Relative to the relationship between these relationships, there is relatively little known regarding the neurological mechanisms through which they give rise to discrete behavioural profiles, and the relationship between such profiles and susceptibility to nicotine.
To answer this question, Faure and colleagues have carried out a study of individual male mice in a semi-natural social environment called Souris-City to learn about their long-term behaviour.
Some of these studies were carried out within a communal living area and others in a separate test area where mice performed a reward seeking task in the isolation of their peers, while in Souris City.
Mice were given individual access to water in a T maze in which they were tasked with completing a specific task, with social, circadian and cognitive behaviours continuously monitored over time with multiple sensors in this environment.
In the test compartment, the mice chose between water and sucrose in individualistic ways that then predicted how they would adapt to the introduction of nicotine as a reward. In addition, the profile that mice developed while isolated in the test area matched the mice’s behaviour in the social environment.
Variations in personality and in dopamine system activity were related to inter-individual differences in decision making strategies. Taken together, the findings indicate that environmental adaptations are acting on dopaminergic activity in response to nicotine exposure to influence behavioural traits and sensitivity to nicotine in an additive manner and may play a role in the aetiology of susceptibility to addiction.
The researchers note these results imply that animals choose different foraging strategies in the context of complex social others. The strategies are characteristic of certain specific animal traits or of the state of the animal’s neural circuits and can also show which responses follow drug challenges.
Overall, the study shows that, rather than one size fits all, exploiting inter-individual variability in behaviour and the neural substrates supporting its dimensional underpinnings is an effective strategy to dissect more complex and fine-grained relationships between neural circuits and behaviour than economics assuming identical responses to task in all mice.
Authors of the study conclude that the use of large naturalistic environments with automated data capture offers a valuable means to study susceptibility to substance abuse.
“Our study demonstrates how social environments determine the way in which individual differences in reward seeking behaviour shape each person’s sensitivity to nicotine,” the authors add.
Reference:
Fayad SL, Reynolds LM, Torquet N, Tolu S, Mondoloni S, Nguyen C, et al. Individualistic reward-seeking strategies that predict response to nicotine emerge among isogenic male mice living in a micro-society. PLOS Biology
