Social Determinants of Inter-Individual Variability and Vulnerability: The Role of Dopamine

Abstract

Individuals differ in their traits and preferences, which shape their interactions, their prospects for survival and their susceptibility to diseases. These correlations are well documented, yet the neurophysiological mechanisms underlying the emergence of distinct personalities and their relation to vulnerability to diseases are poorly understood. Social ties, in particular, are thought to be major modulators of personality traits and psychiatric vulnerability, yet the majority of neuroscience studies are performed on rodents in socially impoverished conditions. Rodent micro-society paradigms are therefore key experimental paradigms to understand how social life generates diversity by shaping individual traits. Dopamine circuitry is implicated at the interface between social life experiences, the expression of essential traits, and the emergence of pathologies, thus proving a possible mechanism to link these three concepts at a neuromodulatory level. Evaluating inter-individual variability in automated social testing environments shows great promise for improving our understanding of the link between social life, personality, and precision psychiatry – as well as elucidating the underlying neurophysiological mechanisms.

Individual variations in reward-seeking adaptability emerge among isogenic mice living in a micro-society and predict their response to nicotine

“…It acts as a modulator, influencing the salience and motivational value assigned to stimuli and guiding the selection of appropriate actions in response to environmental cues. This central position of the dopaminergic system, shared by numerous brain regions, allows us to conceptualize a neural basis for the notion of individuality 20 . Thus, in this sense, our results suggest that a dynamic feedback loop exists between environmental encounters and the dopaminergic system which continually defines animal traits and adaptability to future challenges.…”

Combined Effect of Maternal Separation and Early-Life Immune Activation on Brain and Behaviour of Rat Offspring

“…For example, in schizophrenia patients, interindividual variability has been observed across cognitive tests, giving rise to cognitive heterogeneity as a clinical characteristic of the disorder [80]. A rodent study demonstrated inter-individual variability in social testing environments, attributed to the differential expression of dopamine neurons in response to environmental stimuli [81].…”

Of Mice and Men: The Inter-individual Variability of the Brain's Response to Drugs

“…The examples of variation in ASM responsiveness described above are representative of observations in an increasing number of laboratory studies in neuroscience and other disciplines that have found wide variability in outcomes ( Good and Hardin, 2012 ; Bernard, 2023 ; Marder, 2023 ). Laboratory experiments in experimental psychiatry are particularly prone to this phenomenon ( Pitychoutis et al, 2011 ; Armario and Nadal, 2013 ; Aiello et al, 2015 ; Dellu-Hagedorn et al, 2018 ; Neyazi et al, 2018 ; van der Goot et al, 2021 ; Faure et al, 2022 ). As in our experience, it has often been noted that the common practice of averaging data can lead to erroneous conclusions.…”

“…Even before inducing psychopathology or neurological disease, rodents of the same strain, sex, and age may differ in their intrinsic behavioral characteristics, which may affect the subsequent development of experimentally induced pathologies ( Armario and Nadal, 2013 ; Theilmann et al, 2016 ; Faure et al, 2022 ; Strekalova et al, 2022 ; Löscher and White, 2023 ). For instance, inter-individual differences in baseline anxiety-like behavior (ALB) in Wistar rats affected subsequent amygdala kindling in that only rats with increased baseline ALB before kindling exhibited a lasting increase in ALB after kindling ( Adamec and Shallow, 2000 ).…”