Anterior cingulate cortex, but not amygdala, modulates the anxiogenesis induced by living with conspecifics subjected to chronic restraint stress in male mice

Abstract

Cohabitation with a partner undergoing chronic restraint stress (CRE) induces anxiogenic-like behaviors through emotional contagion. We hypothesized that the anterior cingulate cortex (ACC) and the amygdala would be involved in the modulation of this emotional process. This study investigated the role of the ACC and amygdala in empathy-like behavior (e.g., anxiety-like responses) induced by living with a mouse subjected to CRE. Male Swiss mice were housed in pairs for 14 days and then allocated into two groups: cagemate stress (one animal of the pair was subjected to 14 days of restraint stress) and cagemate control (no animal experienced stress). Twenty-four hours after the last stress session, cagemates had their brains removed for recording FosB labeling in the ACC and amygdala (Exp.1). In experiments 2 and 3, 24 h after the last stress session, the cagemates received 0.1 μL of saline or cobalt chloride (CoCl2 1 mM) into the ACC or amygdala, and then exposed to the elevated plus-maze (EPM) for recording anxiety. Results showed a decrease of FosB labeling in the ACC without changing immunofluorescence in the amygdala of stress cagemate mice. Cohabitation with mice subjected to CRE provoked anxiogenic-like behaviors. Local inactivation of ACC (but not the amygdala) reversed the anxiogenic-like effects induced by cohabitation with a partner undergoing CRE. These results suggest the involvement of ACC, but not the amygdala, in anxiety induced by emotional contagion.

Effects of stress contagion on anxiogenic‐ and orofacial inflammatory pain‐like behaviors with brain activation in mice

“…Stress contagion has been demonstrated in mammals using various animal models [11]. For example, cohabitation with a partner undergoing chronic restraint stress [37], unpredictable stress [38], and social defeat stress [32] induced psychological stress conditions indicated by anxietyand depression-like behaviors in the bystanders. Further, theoretically, given that stress contagion occurs in the bystanders, it is reasonable to speculate that masseter muscle nociception could also increase in the bystanders since various psychological stresses, such as repeated social defeat stress and forced swim stress, could increase deep craniofacial nociception [6,10].…”

Psychobiology and Treatment of Personality Disorders and Related Prominent Traits

“…The limbic system is composed of different subsystems including the amygdala, orbitofrontal cortex, insula, hippocampus and cingulate cortex. It has been proposed that the anterior cingulate cortex, but not the amygdala, is involved in anxiety induced by emotional contagion [19]. This may be because this cortex receives information from the orbitofrontal cortex and connects rewards with actions, thus participating in co-existing emotions [20].…”