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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 (CoCl 2 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., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Silveira, Tavares, Baptista-de-Souza, Carmona, Carneiro de Oliveira, Nunes-de-Souza and Canto-de-Souza.)

Recognizing and sharing emotions are essential for species survival, but in some cases, living with a conspecific in distress condition may induce negative emotional states through empathy-like processes. Studies have reported that stressors promote psychiatric disorders in both, those who suffer directly and who witness these aversive episodes, principally whether social proximity is involved. However, the mechanisms underlying the harmful outcomes of emotional contagion need more studies, mainly in the drug addiction-related behaviors. Here, we investigated the relevance of familiarity and the effects of cohabitation with a partner submitted to chronic stress in the anxiety-like, locomotor sensitization, and consolation behaviors. Male Swiss mice were housed in pairs during different periods to test the establishment of familiarity and the stress-induced anxiety behavior in the elevated plus maze. Another cohort was housed with a conspecific subjected to repeated restraint stress (1 h/day) for 14 days. During chronic restraint the allogrooming was measured and after the stress period mice were tested in the open field for evaluation of anxiety and locomotor cross-sensitization induced by methamphetamine. We found that familiarity was established after 14 days of cohabitation and the anxiogenic behavior appeared after 14 days of stress. Repeated restraint stress also increased anxiety in the open field test and induced locomotor cross-sensitization in the stressed mice and their cagemates. Cagemates also exhibited an increase in the consolation behavior after stress sessions when compared to control mice. These results indicate that changes in drug abuse-related, consolation, and affective behaviors may be precipitated through emotional contagion in familiar conspecifics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Carneiro de Oliveira, Carmona, Casarotto, Silveira, Oliveira and Canto-de-Souza.)

Mice cohabiting with a conspecific in chronic pain display anxiogenesis in the elevated plus-maze (EPM). Given that the anterior cingulate (ACC) and insular (InC) cortices play a role in the modulation of anxiety, pain, and emotional contagion, we investigated (a) the FosB activation in both brain areas and (b) the effects of intra-ACC or -InC injection of cobalt chloride (CoCl 2 , a synaptic blocker), on the anxiety of mice cohabiting with a cagemate suffering pain. Twenty-one days after birth, male Swiss mice were housed in pairs for 14 days to establish familiarity. On the 14th day, mice were divided into two groups: cagemate sciatic nerve constriction (CNC; i.e., one animal of each pair was subjected to sciatic nerve constriction), and cagemate sham (CS; i.e., a similar procedure but without suffering nerve constriction). After that, both groups were housed again with the same pairs for the other 14 days. On the 28th day, mice had their brains removed for the immunoassays analyses (Exp. 1). For experiments 2 and 3, on the 23rd day, the cagemates received guide cannula implantation bilaterally in the ACC or InC and, on the 28th day, they received local injections of saline or CoCl 2 , and then were exposed to the EPM. Results showed that cohabitation with a conspecific with chronic pain decreases and increases neuronal activation (FosB) within the ACC and InC, respectively. Intra-ACC or InC injection of CoCl 2 reversed the anxiogenic effect in those animals that cohabited with a conspecific in chronic pain. ACC and InC seem to modulate anxiety induced by emotional contagion in animals cohabitating with a conspecific suffering pain., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The capacity of rodents to recognize and respond to emotional signs from a conspecific is a valuable adaptive behavior, which provides essential skills for species survival. However, repeated exposure to aversive situations may elicit maladaptive behavioral responses in subjects that experience noxious episodes and their colony members. Previous findings by our group demonstrated that living with a subject in neuropathic pain induces anxiogenic-like behaviors and hypernociception in mice. Whereas chronic pain may be considered a stressful stimulus, we extended our findings on stress-induced emotional transfer. For this purpose, we investigated whether cohabitation with a partner subjected to chronic restraint stress was able to promote alterations in anxiety-like behaviors, pain sensibility and defensive responses. Male Swiss mice were housed in pairs for 14days and then separated into control, stress, and cagemate groups. The stress group was subjected to 14days of restraint stress (1h/day) in the presence of the cagemates, while the pair-housed control group was left undisturbed. A day after last stress session control, stress, and cagemate groups were evaluated using elevated plus maze test, writhing test, and rat exposure test. Results demonstrated that chronic stress attenuated weight gain in the stress group. Moreover, cohabitation with mice subjected to chronic restraint stress induced anxiogenic-like behaviors, pain hypernociception, and alterations in defensive responses in both cagemate and stress groups. These preliminary findings suggest that chronic exposure to aversive stimulus may induce behavioral alterations even in observers., (Copyright © 2017. Published by Elsevier B.V.)

Background and Objective: Fibromyalgia is considered as a combination of physical, psychological and social disabilities. The purpose of the present study was to determine the benefits of aerobic exercise program and progressive relaxation techniques on anxiety, quality of sleep, depression and quality of life in patients with fibromyalgia., Patients and Method: An experimental study was performed with a placebo control group. Fifty-six fibromyalgia patients were randomly assigned to intervention (aerobic exercises+progressive relaxation techniques) and placebo (sham treatment with disconnected magnet therapy device) groups. Outcome measures were anxiety (STAI- State Trait Anxiety Inventory), quality of sleep (Pittsburgh sleep quality index), depression (Beck depression inventory) and quality of life (questionnaire SF-36). Measures were performed at baseline and after 10-weeks treatment., Results: After 10 weeks of treatment, the intervention group showed significant reduction (p<0.05) in sleep duration, trait anxiety and quality of life., Conclusions: The combination of aerobic exercise program and progressive relaxation techniques contribute to improve night rest, trait anxiety and quality of life in patients with fibromyalgia., (Copyright © 2010 Elsevier España, S.L. All rights reserved.)