The neurobiology of pair bonding: Insights from a socially monogamous rodent

The formation of enduring relationships between adult mates (i.e., pair bonds) is an integral aspect of human social behavior and has been implicated in both physical and psychological health. However, due to the inherent complexity of these bonds and the relative rarity with which they are formed in other mammalian species, we know surprisingly little about their underlying neurobiology. Over the past few decades, the prairie vole (Microtus ochrogaster) has emerged as an animal model of pair bonding. Research in this socially monogamous rodent has provided valuable insight into the neurobiological mechanisms that regulate pair bonding behaviors. Here, we review these studies and discuss the neural regulation of three behaviors inherent to pair bonding: the formation of partner preferences, the subsequent development of selective aggression toward unfamiliar conspecifics, and the bi-parental care of young. We focus on the role of vasopressin, oxytocin, and dopamine in the regulation of these behaviors, but also discuss the involvement of other neuropeptides, neurotransmitters, and hormones. These studies may not only contribute to the understanding of pair bonding in our own species, but may also offer insight into the underlying causes of social deficits noted in several mental health disorders.     

Perceptions of partner support among pregnant plurisexual women: A qualitative study

ABSTRACT

Although partner support is an established determinant of mental health, we know little about bisexual and other plurisexual people's experiences of support from their partners. Furthermore, very limited research has examined how bisexual or plurisexual people experience partner support during pregnancy, a significant life stage for many couples. This paper draws from semi-structured interviews with 29 plurisexual women partnered with different-gender (i.e. cisgender male or transgender) partners to examine women's perceptions of partner support during pregnancy. While participants reported many of the same partner support issues and dynamics that have been described in research with monosexual childbearing women, their experiences as plurisexual women were unique in two regards: (a) unconditional acceptance from partners was connected to the partner's support for their plurisexual identities/histories; and (b) social integration support often included shared integration into social networks related to their plurisexual experiences, including sexual networks. These findings offer important implications for sexual and relationship therapists, who can play an important role in helping to foster these plurisexual-specific forms of partner support, and in so doing, improve outcomes for women during this significant life stage.     

Lesions of the vomeronasal organ disrupt mating-induced pair bonding in female prairie voles (Microtus ochrogaster)

The prairie vole (Microtus ochrogaster) is a highly social, monogamous species and displays pair bonding that can be assessed by the presence of selective affiliation with the familiar partner versus a conspecific stranger. In female prairie voles, exposure to a male or to male sensory cues is essential for estrus induction, and the subsequent mating facilitates pair bond formation. In the present study, we examined the role of the vomeronasal organ (VNO) in estrus induction and pair bonding in female prairie voles. VNO lesions did not alter olfaction mediated by the main olfactory system, but did prevent male-induced estrus induction. We by-passed the necessity of the VNO for estrus induction by estrogen priming the females. Despite the fact that all subjects displayed similar levels of mating, social contact and locomotor activities, VNO lesioned females failed to show mating-induced pair bonding whereas intact and sham-lesioned females displayed a robust preference for the familiar partner. Our data not only support previous findings that the VNO is important for estrus induction but also indicate that this structure is crucial for mating-induced pair bonding, suggesting an important role for the VNO in reproductive success in prairie voles.     

The Role of Partner Support Among Women with Depressive Symptoms

Scarce research has explored how sex partners and their provision of social support impact depression among women. The purpose of this study is to examine the role of social support (overall and specific types of support) provided by a sex partner on depressive symptoms among a sample of women (n?=?295). We assessed depression using the Centers for Epidemiological Studies Depression Scale and used a social network inventory to evaluate partner characteristics and types of support provided. Overall 76% (n?=?225) of the sample experienced depressive symptoms in the past 90 days. Approximately one-third of the sample had a partner who provided emotional support (33.9%), financial support (36.6%), or socialization support (40.0%). About 41% of women said their partner offered no support while 16.3% had a partner who gave all three types of support. These findings demonstrate that partners and the level and types of support provided should not be discounted in mental health assessments.     

Lesions of the vomeronasal organ disrupt mating-induced pair bonding in female prairie voles (Microtus ochrogaster)

The prairie vole (Microtus ochrogaster) is a highly social, monogamous species and displays pair bonding that can be assessed by the presence of selective affiliation with the familiar partner versus a conspecific stranger. In female prairie voles, exposure to a male or to male sensory cues is essential for estrus induction, and the subsequent mating facilitates pair bond formation. In the present study, we examined the role of the vomeronasal organ (VNO) in estrus induction and pair bonding in female prairie voles. VNO lesions did not alter olfaction mediated by the main olfactory system, but did prevent male-induced estrus induction. We by-passed the necessity of the VNO for estrus induction by estrogen priming the females. Despite the fact that all subjects displayed similar levels of mating, social contact and locomotor activities, VNO lesioned females failed to show mating-induced pair bonding whereas intact and sham-lesioned females displayed a robust preference for the familiar partner. Our data not only support previous findings that the VNO is important for estrus induction but also indicate that this structure is crucial for mating-induced pair bonding, suggesting an important role for the VNO in reproductive success in prairie voles.     

Human Symbiosis

Abstract

Posttraumatic stress disorder (PTSD) is one of the most common psychiatric disorders among veterans returning tfrom Iraq and Afghanistan. Little research has examined variables that may mediate the relation between PTSD and aspects of social functioning, such as relationship satisfaction and family functioning. In this cross-sectional study, a total of 164 veterans who were seeking VA primary care or mental health care within one year after returning from Iraq and/or Afghanistan were screened for PTSD and completed a series of questionnaires that assessed social functioning, coping, and life satisfaction. Results showed that the 86 (52%) veterans who screened positive for PTSD reported greater difficulties in their relationships with romantic partners, less cohesion in their families, less social support, poorer social functioning, and lower life satisfaction compared to other treatment-seeking veterans. Less social support from the community, excessive worry, decreased acceptance of change, and lower availability of secure relationships mediated the association between PTSD and poor social functioning. The relation between PTSD and lower partner satisfaction was mediated by greater cognitive social avoidance and lower availability of secure relationships. These results suggest that psychotherapeutic interventions that address these mediating variables may help improve social functioning in treatment-seeking veterans with PTSD.     

Neuroendocrine contributions to sexual partner preference in birds

A majority of birds are socially monogamous, providing exceptional opportunities to discover neuroendocrine mechanisms underlying preferences for opposite-sex partners where the sexes form extended affiliative relationships. Zebra finches have been the focus of the most systematic program of research to date in any socially monogamous animal. In this species, sexual partner preference can be partially or largely sex reversed with hormone manipulations during early development, suggesting a role for organizational hormone actions. This same conclusion emerges from research with Japanese quail, which do not form long-term pairs. In zebra finches, social experience manipulations during juvenile development also can sex reverse partner preference, either alone or in combination with an early hormone manipulation. Although there are several candidate brain regions where neural mechanisms could underlie these effects of hormones or social experience, the necessary research has not yet been done to determine their involvement. The neuroendocrinology of avian sexual partner preference is still frontier territory.     

The neuroendocrine basis of social recognition

All social relationships are dependent on an organism's ability to remember conspecifics. Social memory may be a unique form of memory, critical for reproduction, territorial defense, and the establishment of dominance hierarchies in a natural context. In the laboratory, social memory can be assessed reliably by measuring the reduction in investigation of a familiar partner relative to novel conspecifics. The neurohypophyseal neuropeptides oxytocin and vasopressin have been shown to influence a number of forms of social behavior, including affiliation, aggression, and reproduction. This article reviews vasopressin and oxytocin effects on social cognition, particularly the acquisition and retention of social recognition in rats and mice. Studies in rats have demonstrated that vasopressin in specific neural pathways, such as the lateral septum, is necessary for social recognition. As vasopressin facilitates recall when given after an initial encounter, the peptide appears important for the consolidation not the acquisition of a social memory. Although oxytocin has complex effects on social memory in rats, mice with a null mutation of the oxytocin gene are completely socially amnestic without other cognitive deficits evident. As oxytocin given centrally before but not after the initial encounter restores social recognition in these mutant mice, the neuropeptide appears critical for the acquisition rather than the consolidation phase of memory. Oxytocin's effects on social memory are mediated via a discrete cell population in the medial amygdala. These findings support the hypothesis that vasopressin and oxytocin are essential for social memory, although they appear to influence different cognitive processes and may modulate different neural systems. (c) Elsevier Science.     

Bisexual inclusive couples therapy: assessment and treatment with bisexuals in mixed orientation relationships

ABSTRACT

This paper aims to improve understanding of why mixed orientation couples may seek treatment, as well as to support sex and relationship therapists in providing affirmative and respectful services. Mixed orientation relationships, relationships in which partners have different sexual orientation identities, can include a variety of combinations. This paper focuses on mixed orientation relationships in which one partner identifies as bisexual and the other partner does not. A bisexual identity and a mixed orientation relationship are not inherent problems; however, they can create interpersonal and intrapersonal conflicts that may lead to treatment. Therefore, sex and relationship therapists should be aware of special considerations that could improve treatment with bisexuals in mixed orientation relationships with gay, lesbian, and heterosexual partners. It is important for sex and relationship therapists to take additional care in assessing the meaning of sexual orientation to the bisexual partner, what it means to their non-bisexual partner, and what having a mixed orientation relationship means to the couple seeking treatment. The delicate issue of commitment is respectfully explored, and societal myths related to bisexuality are addressed. Affirmative therapy is proposed as an effective theoretical approach, along with the Ex-PLISSIT Model to guide treatment.     

Partner accommodation in posttraumatic stress disorder: Initial testing of the Significant Others’ Responses to Trauma Scale (SORTS)

Posttraumatic stress disorder (PTSD) is associated with myriad relationship problems and psychological distress in partners of individuals with PTSD. This study sought to develop a self-report measure of partner accommodation to PTSD (i.e., ways in which partners alter their behavior in response to patient PTSD symptoms), the Significant Others’ Responses to Trauma Scale (SORTS), and to investigate its reliability and construct validity in 46 treatment-seeking couples. The SORTS demonstrated strong internal consistency and associations with individual and relationship distress. Accommodation was positively correlated with partners’ ratings of patients’ PTSD symptoms, patient self-reported depressive and trait anger severity, and partner self-reported depressive and state anger severity. Accommodation was negatively correlated with patient and partner relationship satisfaction and partners’ perceived social support received from patients. Findings suggest that accommodation may be an attempt to adapt to living with a partner with PTSD but may have negative implications for patient and partner well-being.     

Individual differences in cardiovascular response to social challenge

An important determinant of cardiovascular stress reactivity and morbidity is the individual behavioral strategy of coping with social challenge. This review summarizes the results of a number of studies that we performed in rats, aimed at investigating the relationship between aggression and cardiovascular responsivity under social stress conditions. We show that rats belonging to the 'aggressive tail' of a population are characterized by a higher sympathetic-adrenomedullary activation during social and non-social stress episodes. Wild-type rats are characterized by a larger sympathetic dominance and a higher susceptibility to cardiac arrhythmias during defeat as compared to Wistars. Cardiovascular habituation takes place when social challenge is an intermittent victory experience, whereas no habituation is observed across repeated defeat episodes. Dominant rats whose social dominance is challenged by the aggression of another subject display long-term alterations of heart rate circadian rhythmicity. Such changes are linked to individual proness to defend social dominance: the more the animal counterattacks the aggressor, the smaller the subsequent rhythm disturbance. These data underline how important it is to carefully consider individual differences in aggression and the context in which aggression is expressed, when studying cardiovascular effects of social interactions.     

The role of coping, resilience, and social support in mediating the relation between PTSD and social functioning in veterans returning from Iraq and Afghanistan

Posttraumatic stress disorder (PTSD) is one of the most common psychiatric disorders among veterans returning from Iraq and Afghanistan. Little research has examined variables that may mediate the relation between PTSD and aspects of social functioning, such as relationship satisfaction and family functioning. In this cross-sectional study, a total of 164 veterans who were seeking VA primary care or mental health care within one year after returning from Iraq and/or Afghanistan were screened for PTSD and completed a series of questionnaires that assessed social functioning, coping, and life satisfaction. Results showed that the 86 (52%) veterans who screened positive for PTSD reported greater difficulties in their relationships with romantic partners, less cohesion in their families, less social support, poorer social functioning, and lower life satisfaction compared to other treatment-seeking veterans. Less social support from the community, excessive worry, decreased acceptance of change, and lower availability of secure relationships mediated the association between PTSD and poor social functioning. The relation between PTSD and lower partner satisfaction was mediated by greater cognitive social avoidance and lower availability of secure relationships. These results suggest that psychotherapeutic interventions that address these mediating variables may help improve social functioning in treatment-seeking veterans with PTSD.     

Patterns of interaction in adolescent romantic relationships: Distinct features and links to other close relationships

This study examined the similarities and differences between adolescents’ interactions with romantic partners and those with friends and mothers. Thirty-two adolescents were observed interacting with a romantic partner, a close friend, and their mother. Adolescents and romantic partners engaged in more conflict than adolescents and friends. Adolescents’ affective responsiveness was less positive with romantic partners than with their friends. Additionally, the dyadic positivity was lower in romantic relationships than in friendships. More off-task behavior occurred in romantic relationships than in mother–adolescent relationships. Romantic partners were also less skillful communicators and had lower levels of affective responsiveness than mothers. Adolescents perceived more support and fewer negative interactions in romantic relationships than in relationships with mothers. Consistent with expectations, adolescents’ interactions with romantic partners were associated with those with friends and mothers. Thus, romantic relationships are characterized by distinct patterns of interaction, yet also are associated with other close relationships.     

Transitioning together: a narrative analysis of the support accessed by partners of trans people

Historically trans people have often wrongly been advised that the gender role transition process would result in the breakdown of their relationships, and couples have often been provided with little support through this process. This paper presents an in-depth narrative analysis of the accounts of six cisgender women who have been partnered with trans individuals. It focuses on the support that non-trans partners accessed while their partner progressed through their gender transition. Support was deemed important by all participants in relation to their aim of remaining together with their partners. In terms of whom they accessed support from, participants spoke about interactions with other people in similar situations, with professional therapists, with the Gender Identity Clinics (GICs), and with their partners. In regard to therapy, some reported that their partner's transition was a topic they did not need to discuss. Many reported they had to take an “educator” role in therapy, suggesting that more training for therapists is required. Those who attended GICs with their partner were ambivalent about whether they would have utilised support there if it had been available there, stating that locally situated support was preferable. The paper draws out the clinical implications in relation to these areas.     

Facilitating Other-Awareness in Low-Functioning Children with Autism and Typically-Developing Preschoolers Using Dual-Control Technology

Children with autism are said to lack other-awareness, which restricts their opportunities for peer collaboration. We assessed other-awareness in non-verbal children with autism and typically-developing preschoolers collaborating on a shared computerised picture-sorting task. The studies compared a novel interface, designed to support other-awareness, with a standard interface, with adult and peer partners. The autism group showed no active other-awareness using the standard interface, but revealed clear active other-awareness using the supportive interface. Both groups displayed more other-awareness with the technology than without and also when collaborating with a peer than with an adult partner. We argue that children with autism possess latent abilities to coordinate social interaction that only become evident with appropriate support.     

Dominance and aggression

Dominance is a complex phenomenon mediated by different mechanisms. Various motivations and their mutual correlations determine the tendency to dominate. A subject that is dominant in every situation (i.e., absolutely dominant) is rather an exceptional case. Dominance may be limited to particular situations and exhibited only with some definite partners. One subject may be dominant over one partner and submissive with another. Aggressive behavior is not indispensable to obtain and keep dominance status. It seems that dominance sustained without aggression is more stable than dominance formed on the basis of aggressive display, since experiments on predatory dominance in pairs and groups of cats support such an assumption. Various brain structures were found which are involved in aggressive behavior, but in respect to dominance our experiments point to the role of the dorsal amygdala in predatory dominance.     

Does partner gender influence relationship quality among non-monosexual women?

ABSTRACT

Non-monosexual women (i.e. those attracted to more than one gender) may encounter distinct sexual orientation-based challenges depending on the gender of their current relationship partner. Literature suggests that non-monosexual women in relationships with a male partner may often be assumed to be heterosexual by default, and may struggle with invisibility and lack of validation of their sexual minority identity. The aim of the present study was to examine if non-monosexual women in different-sex relationships experienced increased relationship strain relative to those with same-gender partners, and the potential mechanisms through which this effect may occur. A community sample of 169 non-monosexual women currently in a single partner relationship were recruited. Results indicated that although there was no direct link between partner gender and relationship strain, having a male partner was indirectly linked to greater relationship strain via less outness and less LGB community connectedness, and subsequently greater social isolation and depression. Unexpectedly, those with a male partner also reported greater social isolation independent of their level of outness and LGB community connectedness, suggesting the presence of additional pathways by which partner gender impacts one's sense of social isolation. These findings highlight distinct challenges faced by non-monosexual women in different-sex relationships.     

SOCIAL ISOLATION AND CARDIOVASCULAR DISEASE: AN ATHEROSCLEROTIC PATHWAY?

This paper outlines two pathways through which social support can influence the prevention or progression of cardiovascular disease: health behaviors and neuroendocrine mechanisms. Its primary focus is on neuroendocrine pathways, reviewing data which suggest that lack of social support is etiologically related to coronary artery lesion development through two mechanisms: sympathetic-adrenomedullary influences on platelet function, heart rate and blood pressure in the initial endothelial injury; and pituitary-adrenal cortical factors involved in smooth muscle cell proliferation during progression of the lesion after injury has taken place. It hypothesizes that the buffering effect of social support on the cardiovascular system is mediated primarily through mechanisms associated with the release of oxytocin. © 1998 Elsevier Science Ltd. All rights reserved.     

Is domestic violence followed by an increased risk of psychiatric disorders among women but not among men? A longitudinal cohort study

OBJECTIVE: The association between violence between intimate partners and psychiatric disorders is assumed to reflect a causal link. This assumption is now questioned because several longitudinal studies have documented that adolescents with psychiatric disorders grow up to be overrepresented among adults involved in partner violence. METHOD: The study followed a representative birth cohort prospectively. Adolescent mental disorders were diagnosed at age 18 years. Between ages 24 and 26 years, the authors identified individuals involved in nonabusive relationships versus those involved in clinically abusive relationships (i.e., resulting in injury and/or official intervention). At age 26 years, mental disorders were again diagnosed. RESULTS: Male and female adolescents with psychiatric disorders were at greatest risk of becoming involved in abusive adult relationships. After the authors controlled for earlier psychiatric history, women who were involved in abusive relationships, but not men, had an increased risk of adult psychiatric morbidity. CONCLUSIONS: 1) Psychiatric disorders pose risk for involvement in abusive relationships for both sexes; 2) partner abuse is a contributing source of psychiatric disorders among women but not among men.     

Anterior hypothalamic neural activation and neurochemical associations with aggression in pair-bonded male prairie voles

Male prairie voles (Microtus ochrogaster) display mating-induced pair bonding indicated by social affiliation with their female partners and aggression toward unfamiliar conspecifics. In the present study, we characterized their aggression associated with pair bonding and examined the related neuronal activation and neurochemical architecture. Males that were pair-bonded for 2 weeks displayed intense levels of aggression toward a female or male conspecific stranger but maintained a high level of social affiliation with their familiar female partners. These social interactions induced increases in neural activation, indicated by increased density of Fos-immunoreactive staining (Fos-ir) in several brain regions including the bed nucleus of the stria terminalis (BNST), medial preoptic area (MPOA), paraventricular nucleus (PVN), anterior cortical (AcA), and medial nuclei (MeA) of the amygdala. In the anterior hypothalamus (AH), increased density of Fos-ir staining was found specifically to be associated with aggression toward unfamiliar female or male strangers. In addition, higher densities of AH cells that were stained for tyrosine hydroxylase (TH) or vasopressin (AVP) were also labeled with Fos-ir in these males displaying aggression toward a conspecific stranger compared with males displaying social affiliation toward their female partner. Together, our results indicate that dopamine and vasopressin in the AH may be involved in the regulation of enduring aggression associated with pair bonding in male prairie voles.