Social Involvement Modulates the Response to Novel and Adverse Life Events in Mice.

Luca Colnaghi,Shira Weiss,Mariana Lopez-Rosas,Anna M Snyder,Kelly Clemenza,Amir A Levine,Sarah E Groleau,David A Slattery

doi:10.1371/journal.pone.0163077

Abstract

Epidemiological findings suggest that social involvement plays a major role in establishing resilience to adversity, however, the neurobiology by which social involvement confers protection is not well understood. Hypothesizing that social involvement confers resilience by changing the way adverse life events are encoded, we designed a series of behavioral tests in mice that utilize the presence or absence of conspecific cage mates in measuring response to novel and adverse events. We found that the presence of cage mates increased movement after exposure to a novel environment, increased time spent in the open arms of the elevated plus maze, and decreased freezing time after a foot shock as well as expedited fear extinction, therefore significantly changing the response to adversity. This is a first description of a mouse model for the effects of social involvement on adverse life events. Understanding how social involvement provides resilience to adversity may contribute to the future treatment and prevention of mental and physical illness.

Highlights

In life, we tend to experience situations differently in the presence or absence of social involvement
We found that social involvement is associated with increased exploration as measured in increased movement when mice are exposed to a new environment, increased time spent in the open arms of the elevated plus maze (EPM) after an obligatory exposure to the EPM open arm, and decreased fear memory as measured in a reduction in freezing time in response to a foot shock as well as faster fear extinction
Mice were split into two cohorts and placed on either open arm of the elevated plus maze apparatus, placed either alone (“Singles” Cohort) or in groups of three cage mates (“Groups” Cohort)

Summary

Introduction

We tend to experience situations differently in the presence or absence of social involvement. This is especially important in relation to how we perceive adverse life events, since negative experiences play a determining role in the pathophysiology and time of onset of mental illness [1, 2],. Among the various genetics and environmental factors that could mitigate the potential negative outcomes of exposure to adverse events is social involvement. Moak and Agrawal [4] found that increased perceived interpersonal social support ameliorated the pathogenic influence of exposure to traumatic life events on psychopathology, enhancing individuals' general mental and physical well-being, both in daily life and upon exposure to negative life events

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