Low Empathy-like Behavior in MICE Associates with Impaired Sociability, Emotional Memory, Physiological Stress Reactivity, and Variations in Neurobiological Regulations

Background: Deficits in empathy, in the form of limited prosociality have been proposed to constitute a hallmark of highly prevalent child and adolescent psychiatric disturbance. Additional indices of conduct disorder are constituted by a limited sensitivity to punishment, shallow or deficient affect and reduced physiological reactivity to environmental stressors.

Objectives: Empathy has been reliably addressed in preclinical models through the evaluation of the social transmission of emotional states (physiological state matching): specifically, mice exposed to a painful stimulus display a higher response if in the presence of familiar individual experiencing a higher degree of discomfort, than in isolation. In the present study, we investigated whether a reduction of empathy can be considered a predictor of reduced sociality, sensitivity to punishment, and physiological stress reactivity.

Methods: To this aim, we first evaluated empathy-like behavior in a large group of Balb/cJ mice and then discretized their values in four quartiles. The first (high empathy) and the last (low empathy) quartile constituted the experimental population.

Results: indicate that low-empathy mice are characterized by reduced sociability, impaired memory of negative events, and dampened hypothalamic-pituitary-adrenocortical reactivity to external stressors. Furthermore, we show that low empathy mice exhibit elevated concentrations of oxytocin and vasopressin as well as reduced density of BDNF receptors in selected brain areas.

Conclusions: Thus, not only do present results translate to the preclinical investigation of psychiatric disturbances, but also they can contribute to the study of empathy in terms of its adaptive significance.