Viewing pictures of a romantic partner reduces experimental pain: involvement of neural reward systems

The effect of cognitive behavioral techniques using virtual reality on birth pain: a randomized controlled trial

OBJECTIVE

This study was conducted to investigate the effects of cognitive behavioral techniques using virtual reality on birth pain.

DESING

This study was planned as a double blind randomized controlled experimental study.

SETTING AND PARTICIPANTS

It was conducted with 273 pregnant women who were randomized between July 2016 and June 2019 at maternity hospital located in eastern Anatolia, Turkey.

METHODS

The study included 5 groups. (A: videos of newborn photographs with classical music, B: the video of the newborn photograph album, C: an introductory film of Turkey, D: only classical music, E: routine hospital care). The data were collected by using the "Personal Information Form", "Visual Analogue Scale", "Verbal Rating Scale" and "Virtual Reality".

FINDINGS

Groups show homogeneity in terms of demographic and obstetric variables. It was found that mean Visual Analogue Scale posttest mean score of the group A was 4.98 ± 1.69; group B 4.96 ± 1.72; group C 5.96 ± 2.05; group D 5.60 ± 1.63 and group E 6.38 ± 1.86. Mean Verbal Rating Scale posttest score was found that group A was 2.64 ± 0.73, group B 2.70 ± 0.87, group C 3.18 ± 1.14, group D was 2.80 ± 0.86 and group E was 3.96 ± 1.01. It was obtained that the groups' mean Visual Analogue Scale and Verbal Rating Scale posttest mean scores was statistically significant (p<0.05).

CONCLUSION

In this study, all cognitive techniques applied with virtual reality reduced labor pain during the active phase of labor. Especially the video of newborn photographs with classical music and newborn photograph album have been found more effective than other interventions evaluated in reducing labor pain.

IMPLICATIONS FOR PRACTICE

Midwives can use these techniques to reduce birth pain.

Two sides on the fibromyalgia coin: physical pain and social pain (invalidation)

Although fibromyalgia (FM) has been traditionally defined by the extent of physical pain sites alongside other non-pain symptoms, recent evidence has highlighted the importance of social dimension in definition of pain perception. Social pain or invalidation, which denotes painful feeling following social conflicts or misunderstanding about illness legitimacy, is an important but ignored issue in the FM lexicon. While physical and social pain seem to be different and separate entities, we hypothesize that they are completely intertwined with indistinct borders in FM. Accumulating emergent neuroscience and behavioral evidence highlights the overlapping of physical and social pain in different painful conditions. However, this overlapping seems to reach its maximum in FM. This review sheds more light on the tight interconnectivity between physical and social pain in FM from the perspective of intuitional commonalities, clinical aspects, and shared neural pathways. The conceptualization of FM as an integrative physical-social pain paradigm will move us closer to necessitating the incorporation of social pain in future models of FM diagnosis and management. Key Points • Considering of social pain as one key concept is relatively mute in FM literature. • Overlapping of physical and social pain seems to be unique in FM due to its nature. • Acknowledging social pain in the FM lexicon could shift the paradigm of diagnosis and management of FM patients.

Your presence soothes me: a neural process model of aversive emotion regulation via social buffering

The reduction of aversive emotions by a conspecific's presence-called social buffering-is a universal phenomenon in the mammalian world and a powerful form of human social emotion regulation. Animal and human studies on neural pathways underlying social buffering typically examined physiological reactions or regional brain activations. However, direct links between emotional and social stimuli, distinct neural processes and behavioural outcomes are still missing. Using data of 27 female participants, the current study delineated a large-scale process model of social buffering's neural underpinnings, connecting changes in neural activity to emotional behaviour by means of voxel-wise multilevel mediation analysis. Our results confirmed that three processes underlie human social buffering: (i) social support-related reduction of activity in the orbitofrontal cortex, ventromedial and dorsolateral prefrontal cortices, anterior and mid-cingulate; (ii) downregulation of aversive emotion-induced brain activity in the superficial cortex-like amygdala and mediodorsal thalamus; and (iii) downregulation of reported aversive feelings. Results of the current study provide evidence for a distinct neural process model of aversive emotion regulation in humans by social buffering.

Medial Orbitofrontal De-Activation During Tonic Cold Pain Stimulation: A fMRI Study Examining the Opponent-Process Theory

BACKGROUND

While the concomitant administration of painful and rewarding stimuli tends to reduce the perception of one another, recent evidence shows that pleasant pain relief is experience after the interruption of noxious stimuli. On neurobiological grounds, these opponent processes should translate into decreased activity in brain reward regions during nociceptive stimulation and increased activity in these regions after its interruption. While growing evidence supports the latter assumption, evidence is lacking in humans in support of the former.

METHODS

Twenty-six healthy individuals underwent a functional magnetic resonance imaging (fMRI) session during which they were administered a cold pain stimulation, using a novel paradigm which consisted in a cold gel applied on the right foot of participants.

RESULTS

After the interruption of noxious stimulation, participants experienced significant levels of pleasant pain relief. During cold pain stimulation, brain activations were observed in key regions of the pain matrix (eg, thalamus, primary somatosensory cortex and insula). Conversely, the medial orbitofrontal cortex was found to be de-activated. Medial orbitofrontal de-activations were negatively correlated with subclinical pain symptoms.

DISCUSSION

Our results show that a key brain reward region (eg, medial orbitofrontal cortex) is de-activated during cold pain stimulation, a result which is consistent with one of the central assumptions of the opponent-process theory. On methodological grounds, our results show that the cold gel applied to the foot can be used to trigger activations in the pain matrix, and that the interruption of the cold pressor test elicits significant levels of pleasant pain relief. fMRI studies on pain-reward interactions in chronic pain patients are warranted.

Physical Pain as Pleasure: A Theoretical Perspective

Physical pain represents a common feature of Bondage and Discipline/Dominance and Submission/Sadism and Machochism (BDSM) activity. This article explores the literature accounting for how painful stimuli may be experienced as pleasurable among practitioners of BDSM, and contrasting this with how it is experienced as painful among non-BDSM individuals. We reviewed the available literature on pain and on BDSM, and used the findings to postulate a theory accounting for how painful stimuli are experienced as pleasurable. Our theory was then checked with BDSM practitioners. The emotional, physiological, and psychological elements of pain interact to facilitate the experience of pain as pleasure in BDSM. A multitude of interconnected factors was theorized to alter the experience of BDSM pain, including: neural networks, neurotransmitters, endogenous opioids and endocannabinoids, visual stimuli, environmental context, emotional state, volition and control, interpersonal connection, sexual arousal, and memories. The experience of pain in this context can bring about altered states of consciousness that may be similar to what occurs during mindfulness meditation. Through understanding the mechanisms by which pain may be experienced as pleasure, the role of pain in BDSM is demystified and, it is hoped, destigmatized.

Pain and satisfaction: healthcare providers' facial appearance matters

Trait inferences based solely on facial appearance affect many social decisions. Here we tested whether the effects of such inferences extend to the perception of physical sensations. In an actual clinical setting, we show that healthcare providers' facial appearance is a strong predictor of pain experienced by patients during a medical procedure. The effect was specific to familiarity: facial features of healthcare providers that convey feelings of familiarity were associated with a decrease in patients' perception of pain. In addition, caring appearance of the healthcare providers was significantly related to patients' satisfaction with the care they received. Besides indicating that rapid, unreflective trait inferences from facial appearance may affect important healthcare outcomes, these findings contribute to the understanding of the mechanisms underlying social modulation of pain perception.

The Scent of a Good Night's Sleep: Olfactory Cues of a Romantic Partner Improve Sleep Efficiency

Almost nothing is known about whether exposure to the scent of loved ones influences sleep. In the current study, 155 participants spent 2 nights with their partner's scent and 2 nights with a control scent (in random order). Sleep was measured in two ways: sleep efficiency (via actigraphy) and perceived sleep quality (via self-report). Sleep efficiency was higher when participants were exposed to their partner's scent. This increase occurred regardless of participants' beliefs about the origin of the scent. Perceived sleep quality was higher when participants believed that they were smelling their partner's scent. Exposure to a partner's scent led sleep efficiency to increase by more than 2% on average, an improvement similar in magnitude to the effect of melatonin on sleep. The current work speaks to the critical role of olfaction in communication and reveals that social scents can impact sleep.

The effect of perceived social support on chemotherapy-related symptoms in patients with breast cancer: A prospective observational study

OBJECTIVE

Few studies have examined the effect of perceived social support (PSS) on chemotherapy-related symptoms (CRS). This study examined the effect of PSS on CRS in 184 patients with breast cancer.

METHODS

Participants were consecutively enrolled from a tertiary general hospital in Seoul, South Korea. CRS were assessed eight times, from before the first neoadjuvant chemotherapy to six months after the end of neoadjuvant chemotherapy, with the MD Anderson Symptom Inventory. PSS was evaluated once, before the first neoadjuvant chemotherapy session, using the Multidimensional Scale of Perceived Social Support (MSPSS). Two groups were formed based on MSPSS scores: the low PSS group (n = 62) and the moderate-to-high PSS group (n = 122). Linear mixed model analyses were used to compare the change in CRS severity between the two groups during chemotherapy.

RESULTS

Results indicated a significant group-by-time (low PSS or moderate-to-high PSS; 8 periods of chemotherapy) interaction for pain (p = .005), nausea (p = .033), insomnia (p < .001), distress (p = .003), dyspnea (p = .014), memory loss (p = .021), vomiting (p = .016), and numbness (p = .008) in which the moderate-to-high PSS group showed significantly lower levels of increase in those symptoms during chemotherapy. Moreover, the effect of PSS on CRS differed depending on the sources of PSS.

CONCLUSION

Patients with moderate-to-high PSS experience less severe CRS compared with patients with low PSS during chemotherapy. The current findings indicate the potential benefits of providing social support in the management of CRS.

A novel theory on the predictive value of variation in the β-endorphin system on the risk and severity of PTSD

Despite growing interest in genetic and psychosocial indicators of heightened susceptibility to posttraumatic stress disorder (PTSD), a predictive model, which explains why some individuals develop PTSD in response to life-threatening traumatic events, while others, when faced with the same or similar experiences, do not, has thus far remained out of reach. In this paper, we review the literature on gene-environment interactions in β-endorphin system functioning with regard to PTSD and suggest that variation, both genetic and with regard to environmental stimuli, in systems which, like the β-endorphin system, distort human perception of life-threatening traumatic experiences may account for some of the variance in resilience to the disorder. Given the role of β-endorphin in both social connections and physical exercise, this becomes especially relevant with regard to military selection, training, and leadership processes.

Resilience and the brain: a key role for regulatory circuits linked to social stress and support

Given the high prevalence and burden of mental disorders, fostering the understanding of protective factors is an urgent issue for translational medicine in psychiatry. The concept of resilience describes individual and environmental protective factors against the backdrop of established adversities linked to mental illness. There is convergent evidence for a crucial role of direct as well as indirect adversity impacting the developing brain, with persisting effects until adulthood. Direct adversity may include childhood maltreatment and family adversity, while indirect social adversity can include factors such as urban living or ethnic minority status. Recently, research has begun to examine protective factors which may be able to buffer against or even reverse these influences. First evidence indicates that supportive social environments as well as trait-like individual protective characteristics might impact on similar neural substrates, thus strengthening the capacity to actively cope with stress exposure in order to counteract the detrimental effects evoked by social adversity. Here, we provide an overview of the current literature investigating the neural mechanisms of resilience with a putative social background, including studies on individual traits and genetic variation linked to resilience. We argue that the regulatory perigenual anterior cingulate cortex and limbic regions, including the amygdala and the ventral striatum, play a key role as crucial convergence sites of protective factors. Further, we discuss possible prevention and early intervention approaches targeting both the individual and the social environment to reduce the risk of psychiatric disorders and foster resilience.

Social support modulates the neural correlates underlying social exclusion

Ostracism threatens the human need for social interactions, with negative consequences on cognition, affect and behavior. Understanding the mechanisms that can alleviate these consequences has therefore become an important research agenda. In this study, we used behavioral and fMRI measures to advance our understanding how social support can buffer the negative effects of social exclusion. We focused on two different types of support from a friend: emotional support, conveyed by gentle touch and appraisal support, implemented as informative text messages. Seventy-one female participants underwent fMRI scanning while playing a virtual ball-tossing game in the course of which they were excluded. Two consecutive runs of the game were separated according to the participant’s experimental condition (appraisal support, emotional support and no support). Results showed that the experience of social exclusion is modulated by the type of support received. Specifically, emotional support decreased negative emotions and anterior insula activity, while appraisal support increased negative emotions, with concomitant increase of subgenual anterior cingulate cortex and decrease of temporal-parietal junction activity. These divergent effects of social support point to the necessity to characterize whether and under which conditions it represents an effective and positive resource to alleviate the negative consequences of social exclusion.

Toxic Nightlife Relationships, Substance Abuse, and Mental Health: Is There a Link? A Qualitative Case Study of Two Patients

Introduction and Aims: This article explores the role of toxic close relationships in night life on substance use disorders and mental health conditions. We also contrast the quality and effects of social relationships when doing drugs with those produced by a mental health program that fosters quality relationships between patients. Design and Methods: This qualitative case study was carried out at a mental health day care center of a hospital in Malaga (Spain). The cases of two patients with severe mental disorders and a history of drug addiction were analyzed. Data were collected through in-depth interviews with every patient, semi-structured interviews about each patient with the psychologist of the medical team of the program, and medical documentation. The analysis involved a combination of inductive and deductive approaches. Results: The analysis of the data revealed, on the one hand, the influence of toxic relationships in nightlife, including violent sporadic sexual relationships, in the initiation and persistence of substance use that took part of the mental health disorder in these patients. On the other hand, the findings show that these participants' current involvement in a mental health program, which fosters quality relationships between patients, has brought emotional benefits to both of them. Discussion and Conclusion: This paper points out the relevance of considering quality of social relationships when examining substance use disorders and related mental health problems. Additionally, the findings indicate the importance of fostering quality peer relationships in mental health rehabilitation programs addressed to patients with histories of drug addiction to improve treatment outcome.

Socioneuroscience and its contributions to conscious versus unconscious volition and control. The case of gender violence prevention

Research in neuroscience is being very fruitful in providing evidence about the influence of social experience in the architecture and functioning of the brain. In so doing, neuroscience is posing new and fascinating research questions to examine in depth the social processes that produce those neural changes. To undertake the task of tackling such research questions, evidence from the social sciences are necessary to better understand how different types of social experiences produce different types of synaptic changes and even modify subcortical brain structures differently. It will be the dialogue between neuroscience, other natural sciences and the social sciences which will advance the scientific understanding of plastic changes in the brain which result from complex social experiences that have been traditionally studied by the social sciences. Socioneuroscience constitutes the arena for such interdisciplinary dialogue and research that can both advance the scientific understanding of the human brain and provide evidence-based solutions to most urgent social problems. Socioneuroscience studies the relations between the human brain and social interactions taking into account knowledge from all social sciences and the natural sciences. Processes of conscious versus unconscious social volition and control is one central area of inquiry in socioneuroscience. In this article, we discuss the dominant coercive discourse in society -which presents males with aggressive attitudes and behaviors as more attractive- as an example of social control of human volition which imprisons many individuals' sexual freedom. However, due to brain plasticity, certain experiences that question such dominant discourse and empty violence from attractiveness open up the possibility for the individual and the society to break free from the neural wiring imposed by the dominant coercive discourse and, in the words of Santiago Ramón y Cajal, be ourselves “the architects of our brain”, contributing to overcome violence against women.

Neuroimaging of Pain: Human Evidence and Clinical Relevance of Central Nervous System Processes and Modulation

Neuroimaging research has demonstrated definitive involvement of the central nervous system in the development, maintenance, and experience of chronic pain. Structural and functional neuroimaging has helped elucidate central nervous system contributors to chronic pain in humans. Neuroimaging of pain has provided a tool for increasing our understanding of how pharmacologic and psychologic therapies improve chronic pain. To date, findings from neuroimaging pain research have benefitted clinical practice by providing clinicians with an educational framework to discuss the biopsychosocial nature of pain with patients. Future advances in neuroimaging-based therapeutics (e.g., transcranial magnetic stimulation, real-time functional magnetic resonance imaging neurofeedback) may provide additional benefits for clinical practice. In the future, with standardization and validation, brain imaging could provide objective biomarkers of chronic pain, and guide treatment for personalized pain management. Similarly, brain-based biomarkers may provide an additional predictor of perioperative prognoses.

Cultural Attachment: From Behavior to Computational Neuroscience

Cultural attachment (CA) refers to processes that allow culture and its symbols to provide psychological security when facing threat. Epistemologically, whereas we currently have an adequate predictivist model of CA, it is necessary to prepare for a mechanistic approach that will not only predict, but also explain CA phenomena. Toward that direction, we here first examine the concepts and mechanisms that are the building blocks of both the prototypical maternal attachment as well as CA. Based on existing robust neuroscience models we associate these concepts and mechanisms with bona fide neurobiological functions to advance an integrative neurobiological model of CA. We further discuss the unresolved relationship of CA to other similar socio-cognitive concepts such as familiarity. Overall aim of the paper is to highlight the importance of integrating CA theory to computational approaches to culture and evolution (such as predictive processing computations explaining niche construction), as this will allow a dynamic interpretation of cultural processes.

Implications for Reward Processing in Differential Responses to Loss: Impacts on Attachment Hierarchy Reorganization

When an attachment relationship is severed, so is homeostatic maintenance, leading to dysregulation of multiple physiological systems. Expanding upon Sbarra and Hazan's original model, we suggest that the degree to which an individual's physiological systems remain dysregulated depends on the state of one's attachment hierarchy-namely, whether an individual continues to seek a lost partner for support as their primary attachment figure. To recover from the loss of a romantic partner, an individual's attachment hierarchy must be reorganized. Our model proposes that an individual will go through a series of physiological changes before their attachment hierarchy is reorganized, which can either help or hinder their recovery. We consider the role of reward processing, including endogenous opioids, in this recovery process. Along the way, we identify mechanisms for continued dysregulation of biological systems among those who take longer to recover from a loss.

Pain-related nucleus accumbens function: modulation by reward and sleep disruption

The nucleus accumbens (NAc) has been implicated in sleep, reward, and pain modulation, but the relationship between these functional roles is unclear. This study aimed to determine whether NAc function at the onset and offset of a noxious thermal stimulus is enhanced by rewarding music, and whether that effect is reversed by experimental sleep disruption. Twenty-one healthy subjects underwent functional magnetic resonance imaging scans on 2 separate days after both uninterrupted sleep and experimental sleep disruption. During functional magnetic resonance imaging scans, participants experienced noxious stimulation while listening to individualized rewarding or neutral music. Behavioral results revealed that rewarding music significantly reduced pain intensity compared with neutral music, and disrupted sleep was associated with decreased pain intensity in the context of listening to music. In whole-brain family-wise error cluster-corrected analysis, the NAc was activated at pain onset, but not during tonic pain or at pain offset. Sleep disruption attenuated NAc activation at pain onset and during tonic pain. Rewarding music altered NAc connectivity with key nodes of the corticostriatal circuits during pain onset. Sleep disruption increased reward-related connectivity between the NAc and the anterior midcingulate cortex at pain onset. This study thus indicates that experimental sleep disruption modulates NAc function during the onset of pain in a manner that may be conditional on the presence of competing reward-related stimuli. These findings point to potential mechanisms for the interaction between sleep, reward, and pain, and suggest that sleep disruption affects both the detection and processing of aversive stimuli that may have important implications for chronic pain.

Brain activity sustaining the modulation of pain by empathetic comments

Empathetic verbal feedback from others has been shown to alleviate the intensity of experimental pain. To investigate the brain changes associated with this effect, we conducted 3T-fMRI measurements in 30 healthy subjects who received painful thermal stimuli on their left hand while overhearing empathetic, neutral or unempathetic comments, supposedly made by experimenters, via headsets. Only the empathetic comments significantly reduced pain intensity ratings. A whole-brain BOLD analysis revealed that both Empathetic and Unempathetic conditions significantly increased the activation of the right anterior insular and posterior parietal cortices to pain stimuli, while activations in the posterior cingulate cortex and precuneus (PCC/Prec) were significantly stronger during Empathetic compared to Unempathetic condition. BOLD activity increased in the DLPFC in the Empathetic condition and decreased in the PCC/Prec and vmPFC in the Unempathetic condition. In the Empathetic condition only, functional connectivity increased significantly between the vmPFC and the insular cortex. These results suggest that modulation of pain perception by empathetic feedback involves a set of high-order brain regions associated with autobiographical memories and self-awareness, and relies on interactions between such supra-modal structures and key nodes of the pain system.

Attenuation of Pain Perception Induced by the Rubber Hand Illusion

Adaptive behavior usually requires accurate representations of body positions and ownership, which rely on integration of multiple sources of sensory information. The rubber hand illusion (RHI) presents a compelling example demonstrating that the combination of visual and tactile signals strongly influences the subjective experience of body ownership. However, it still remains unclear how the perception of body ownership in turn alters other aspects of sensory processing, such as pain perception. In the present study, we examined whether the RHI could modulate the subjective experience of pain. We set three conditions corresponding to different levels of ownership of the rubber hand: the synchronous condition in which the rubber and the real hand were simultaneously stroked; the asynchronous condition in which the two hands were asynchronously stroked; the own-hand-only condition in which only the real hand was stroked. Results from the screening experiment indicated that subjects experienced the stronger RHI in the synchronous condition, compared with the strength of RHI in the other two conditions. In the main experiment, subjects were requested to report the intensity and unpleasantness of pain evoked by laser stimuli under the three stroking conditions. Results showed that pain ratings were significantly lower under the synchronous condition than those under the other two conditions, suggesting the RHI could induce a significant analgesic effect. Furthermore, the correlation analysis showed that the degree of the analgesic effect was positively correlated with the RHI strength across individuals. Taken together, these results suggest an analgesic effect of the RHI and support the potential usage of visual illusions in future translational research on pain.

An attachment theoretical perspective for the neural representation of close others

Recent investigations in neuroscience elucidate the neural basis of close other cognitive representations, which serve functions central to our health and happiness. Yet, there are persistent barriers to this research, including disparate research methods and the absence of a common theoretical background. The present review connects neuroimaging and attachment theory within a novel social, cognitive and affective framework. We apply attachment theory to understand why we would expect cognitive representations of close others to be different from other social neural representations. Developing reliable markers of attachment is a critical step in mapping close other neural representations. We then examine existing neuroimaging literature on close other representations, highlighting the recruitment of neural systems supporting reward, motivation and distress alleviation, in addition to the mirror neuron system, default network and salience network. We then review the methodologies of past studies, revealing a diverse array of self-report measures assessing `closeness' and social cognitive tasks that, taken together, preclude meaningful synthesis of findings. Lastly, we discuss specific behavioral measures of attachment and closeness with recommendations for the field. This attachment framework integrates brain and behavioral sciences and unites theoretical principles with empirical methods to further our understanding of how the brain represents close others.

Cingulate-mediated approaches to treating chronic pain

Anterior midcingulate cortex (aMCC) has been shown to be involved in most of the functional imaging studies investigating acute pain. For 10-15 years, it has even been a main focus of interest for pain studies, considering that neurons in the aMCC could encode for pain intensity. This latter function is now presumed to occur in secondary somatosensory (SII) area and/or insular cortices, while anterior cingulate cortex (ACC) is supposed to sustain other functions such as pain-related attention, arousal, motor withdrawal reflex, pain modulations, and engagement of endogenous pain control system. The quantitative imaging studies have shown a rich density of opioid receptors in the ACC. Thus, the perigenual subdivision has been suggested to participate in top-down controls of pain, (including the placebo effects known to be opioid mediated), mainly (but not exclusively) through the connection between the orbitofrontal/subgenual ACC and the periaqueductal gray (PAG). From this rationale, this area may lead to neurosurgical targeting including electrical stimulation for intractable pain in the future. A number of imaging studies have also reported activity changes in the posterior cingulate cortex during pain and proposed its speculative involvement to modulate the conscious experience of pain according to elements from the context and awareness of the self and others.

Behavioral interventions in health neuroscience

Many chronic health concerns (obesity, addiction, stress, chronic pain, and depression) have garnered recent attention for their increasing frequency, intractability, and serious health consequences. Because they are often difficult to treat and there are not always effective pharmacological treatments, many patients are pursuing behavioral interventions for these conditions. Experimental behavioral intervention studies have shown some efficacy for health, but the mechanisms for these treatments are not well understood. Health neuroscience is a burgeoning field that seeks to link neural function and structure with physical and mental health. Through this lens, initial studies have begun to investigate how behavioral interventions modulate neural function in ways that lead to improvements in health markers and outcomes. Here, we provide a review of these studies in terms of how they modulate key neurobiological systems, and how modulation of these systems relates to physical health and disease outcomes. We conclude with discussion of opportunities for future research in this promising area of study.

Oxytocin enhances the pain-relieving effects of social support in romantic couples

Social support plays a vital role in physical and mental well-being. The neuropeptide hormone oxytocin (OXT) has been implicated in modulating pair-bonding and affiliative behaviors, but whether OXT contributes to the analgesic effects of a romantic partner's touch remains elusive. In the present randomized placebo-controlled, between-group, functional magnetic resonance imaging study involving 194 healthy volunteers (97 heterosexual couples), we tested the effects of intranasal OXT (24 IU) on handholding as a common mode of expressing emotional support in romantic couples. We scanned the subjects while brief electric shocks were administered. The subjects assumed that they received social support from either their romantic partner or an unfamiliar person. Unbeknown to the subject, in the partner and stranger support conditions, the same male experimenter always held the subject's left hand. Partner support was most effective in reducing the unpleasantness of electric shocks, and OXT further attenuated the unpleasantness across conditions. On the neural level, OXT significantly augmented the beneficial effects of partner support, as evidenced by a stronger decrease of neural responses to shocks in the anterior insula (AI), a stronger activity increase in the middle frontal gyrus (MFG), and a strengthened functional coupling between the AI and MFG. Our results support the notion that OXT specifically modulates the beneficial effects of social support in romantic couples by concomitantly reducing pain-associated activity and increasing activity linked to cognitive control and pain inhibition. We hypothesize that impaired OXT signaling may contribute to the experience of a lack of partner support.

Sex- and context-dependent effects of oxytocin on social sharing

We interact socially and form bonds with others because such experiences are rewarding. However, an insecure attachment style or social anxiety can reduce these rewarding effects. The neuropeptide oxytocin (OXT) may facilitate social interactions either by increasing their rewarding experience or by attenuating anxiety, although effects can be sex- and attachment-style dependent. In this study, 128 pairs of same-sex friends completed a social sharing paradigm in a double-blind, placebo-controlled, between-subject design with one friend inside an MRI scanner and the other in a remote behavioral testing room. In this way we could examine whether intranasal-OXT differentially modulated the emotional impact of social sharing and associated neural processing. Additionally, we investigated if OXT effects were modulated by sex and attachment style. Results showed that in women, but not men, OXT increased ratings for sharing stimuli with their friend but not with a stranger, particularly in the friend in the scanner. Corresponding neuroimaging results showed that OXT decreased both amygdala and insula activity as well as their functional connectivity in women when they shared with friends but had the opposite effect in men. On the other hand, OXT did not enhance responses in brain reward circuitry. In the PLC treated group amygdala responses in women when they shared pictures with their friend were positively associated with attachment anxiety and OXT uncoupled this. Our findings demonstrate that OXT facilitates the impact of sharing positive experiences with others in women, but not men, and that this is associated with differential effects on the amygdala and insula and their functional connections. Furthermore, OXT particularly reduced increased amygdala responses during sharing in individuals with higher attachment anxiety. Thus, OXT effects in this context may be due more to reduced anxiety when sharing with a friend than to enhanced social reward.

The Oxytocin Receptor: From Intracellular Signaling to Behavior

The many facets of the oxytocin (OXT) system of the brain and periphery elicited nearly 25,000 publications since 1930 (see FIGURE 1 , as listed in PubMed), which revealed central roles for OXT and its receptor (OXTR) in reproduction, and social and emotional behaviors in animal and human studies focusing on mental and physical health and disease. In this review, we discuss the mechanisms of OXT expression and release, expression and binding of the OXTR in brain and periphery, OXTR-coupled signaling cascades, and their involvement in behavioral outcomes to assemble a comprehensive picture of the central and peripheral OXT system. Traditionally known for its role in milk let-down and uterine contraction during labor, OXT also has implications in physiological, and also behavioral, aspects of reproduction, such as sexual and maternal behaviors and pair bonding, but also anxiety, trust, sociability, food intake, or even drug abuse. The many facets of OXT are, on a molecular basis, brought about by a single receptor. The OXTR, a 7-transmembrane G protein-coupled receptor capable of binding to either Gαior Gαqproteins, activates a set of signaling cascades, such as the MAPK, PKC, PLC, or CaMK pathways, which converge on transcription factors like CREB or MEF-2. The cellular response to OXT includes regulation of neurite outgrowth, cellular viability, and increased survival. OXTergic projections in the brain represent anxiety and stress-regulating circuits connecting the paraventricular nucleus of the hypothalamus, amygdala, bed nucleus of the stria terminalis, or the medial prefrontal cortex. Which OXT-induced patterns finally alter the behavior of an animal or a human being is still poorly understood, and studying those OXTR-coupled signaling cascades is one initial step toward a better understanding of the molecular background of those behavioral effects.

Social domain based modulation of neural responses to threat: The different roles of romantic partners versus friends

The neural circuitry associated with threat regulation in the absence of other people is well established. An examination of threat regulatory processes with people from different domains of an individual's social world is key to understanding social emotion regulation and personality functioning conceptualised as social domain organisation. In this study, 42 healthy female participants completed functional magnetic imaging sessions in which they underwent a scan in the presence of a romantic partner or friend, whilst completing a threat of shock task. In the presence of a romantic partner vs. friend, we found a reduction in amygdala activation to threat vs. safe trials over time. Furthermore, in the presence of a romantic partner vs. friend we observed greater subgenual anterior cingulate cortex and ventromedial prefrontal cortex activation to threat vs. safe trials overall. The results support the hypothesis that recruitment of threat regulation circuitry is modulated by romantic partner relative to another person well-known to the individual. Future work needs to examine neural responses to a wider range of stimuli across more social domains, and implications of failures of this neural organisation for psychopathology.

Role of the Prefrontal Cortex in Pain Processing

The prefrontal cortex (PFC) is not only important in executive functions, but also pain processing. The latter is dependent on its connections to other areas of the cerebral neocortex, hippocampus, periaqueductal gray (PAG), thalamus, amygdala, and basal nuclei. Changes in neurotransmitters, gene expression, glial cells, and neuroinflammation occur in the PFC during acute and chronic pain, that result in alterations to its structure, activity, and connectivity. The medial PFC (mPFC) could serve dual, opposing roles in pain: (1) it mediates antinociceptive effects, due to its connections with other cortical areas, and as the main source of cortical afferents to the PAG for modulation of pain. This is a ‘loop’ where, on one side, a sensory stimulus is transformed into a perceptual signal through high brain processing activity, and perceptual activity is then utilized to control the flow of afferent sensory stimuli at their entrance (dorsal horn) to the CNS. (2) It could induce pain chronification via its corticostriatal projection, possibly depending on the level of dopamine receptor activation (or lack of) in the ventral tegmental area-nucleus accumbens reward pathway. The PFC is involved in biopsychosocial pain management. This includes repetitive transcranial magnetic stimulation, transcranial direct current stimulation, antidepressants, acupuncture, cognitive behavioral therapy, mindfulness, music, exercise, partner support, empathy, meditation, and prayer. Studies demonstrate the role of the PFC during placebo analgesia, and in establishing links between pain and depression, anxiety, and loss of cognition. In particular, losses in PFC grey matter are often reversible after successful treatment of chronic pain.

Pleasant Pain Relief and Inhibitory Conditioned Pain Modulation: A Psychophysical Study

Background

Inhibitory conditioned pain modulation (ICPM) is one of the principal endogenous pain inhibition mechanisms and is triggered by strong nociceptive stimuli. Recently, it has been shown that feelings of pleasantness are experienced after the interruption of noxious stimuli. Given that pleasant stimuli have analgesic effects, it is therefore possible that the ICPM effect is explained by the confounding effect of pleasant pain relief. The current study sought to verify this assumption.

Methods

Twenty-seven healthy volunteers were recruited. Thermal pain thresholds were measured using a Peltier thermode. ICPM was then measured by administering a tonic thermal stimulus before and after a cold-pressor test (CPT). Following the readministration of the CPT, pleasant pain relief was measured for 4 minutes. According to the opponent process theory, pleasant relief should be elicited following the interruption of a noxious stimulus.

Results

The interruption of the CPT induced a mean and peak pleasant pain relief of almost 40% and 70%, respectively. Pleasant pain relief did not correlate with ICPM amplitude but was positively correlated with pain level during the CPT. Finally, a negative correlation was observed between pleasant pain relief and anxiety.

Discussion

Results show that the cessation of a strong nociceptive stimulus elicits potent pleasant pain relief. The lack of correlation between ICPM and pleasant pain relief suggests that the ICPM effect, as measured by sequential paradigms, is unlikely to be fully explained by a pleasant pain relief phenomenon.

Dissociable patterns of brain activity for mentalizing about known others: a role for attachment

The human brain tracks dynamic changes within the social environment, forming and updating representations of individuals in our social milieu. This mechanism of social navigation builds an increasingly complex map of persons with whom we are familiar and form attachments to guide adaptive social behaviors. We examined the neural representation of known others along a continuum of attachment using fMRI. Heterosexual adults (N = 29, 16 females), in romantic relationships for more than 2 years, made trait judgments for a romantic partner, parent, close friend, familiar acquaintance and self-during scanning. Multivariate analysis, partial least squares, was used to identify whole-brain patterns of brain activation associated with trait judgments of known others across a continuum of attachment. Across conditions, trait judgments engaged the default network and lateral prefrontal cortex. Judgments about oneself and a partner were associated with a common activation pattern encompassing anterior and middle cingulate, posterior superior temporal sulcus, as well as anterior insula. Parent and close friend judgments engaged medial and anterior temporal lobe regions. These results provide novel evidence that mentalizing about known familiar others results in differential brain activity. We provide initial evidence that the representation of adult attachment is a distinguishing feature of these differences.

Social Monogamy in Nonhuman Primates: Phylogeny, Phenotype, and Physiology

Monogamy as a social system has been both a scientific puzzle and a sociocultural issue for decades. In this review, we examine social monogamy from a comparative perspective with a focus on primates, our closest genetic relatives. We break down monogamy into component elements, including pair-bonding and partner preference, mate guarding or jealousy, social attachment, and biparental care. Our survey of primates shows that not all features are present in species classified as socially monogamous, in the same way that human monogamous relationships may not include all elements-a perspective we refer to as "monogamy à la carte." Our review includes a survey of the neurobiological correlates of social monogamy in primates, exploring unique or common pathways for the elemental components of monogamy. This compilation reveals that the components of monogamy are modulated by a suite of androgenic steroids, glucocorticoid hormones, the nonapeptide hormones oxytocin and vasopressin, and other neurotransmitter systems (e.g., dopamine and opioids). We propose that efforts to understand the biological underpinnings of complex human and animal sociosexual relationships will be well served by exploring individual phenotypic traits, as opposed to pursuing these questions with the assumption that monogamy is a unitary trait or a species-specific characteristic.

Subjective General Health and the Social Regulation of Hypothalamic Activity

OBJECTIVE

Social support is associated with better health. This association may be partly mediated through the social regulation of adrenomedullary activity related to poor cardiovascular health and glucocorticoid activity known to inhibit immune functioning. These physiological cascades originate in the hypothalamic areas that are involved in the neural response to threat. The aim of the study investigated whether the down regulation, by social support, of hypothalamic responses to threat is associated with better subjective health.

METHODS

A diverse community sample of seventy-five individuals, aged 23 to 26 years, were recruited from an ongoing longitudinal study. Participants completed the Short Form Health Survey, a well-validated self-report measure used to assess subjective general health. They were scanned, using functional magnetic resonance imaging, during a threat of shock paradigm involving various levels of social support, which was manipulated using handholding from a close relational partner, a stranger, and an alone condition. We focused on a hypothalamic region of interest derived from an independent sample to examine the association between hypothalamic activity and subjective general health.

RESULTS

Results revealed a significant interaction between handholding condition and self-reported general health (F(2,72) = 3.53, p = .032, partial η = 0.05). Down regulation of the hypothalamic region of interest during partner handholding corresponded with higher self-ratings of general health (ß = -0.31, p = .007).

CONCLUSIONS

Higher self-ratings of general health correspond with decreased hypothalamic activity during a task that blends threat with supportive handholding. These results suggest that associations between social support and health are partly mediated through the social regulation of hypothalamic sensitivity to threat.

Heart rate variability is associated with psychosocial stress in distinct social domains

OBJECTIVE

Psychosocial stress is associated with substantial morbidity and mortality. Accordingly, there is a growing interest in biomarkers that indicate whether individuals show adaptive (i.e., stress-buffering and health-promoting) or maladaptive (i.e., stress-escalating and health-impairing) stress reactions in social contexts. As heart rate variability (HRV) has been suggested to be a biomarker of adaptive behavior during social encounters, it may be possible that inter-individual differences in HRV are associated with inter-individual differences regarding stress in distinct social domains.

METHODS

To test this hypothesis, resting state HRV and psychosocial stress was assessed in 83 healthy community-dwelling individuals (age: 18-35years). HRV was derived from heart rate recordings during spontaneous and instructed breathing to assess the robustness of possible associations between inter-individual differences in HRV and inter-individual differences in psychosocial stress. Psychosocial stress was determined with a self-report questionnaire assessing stress in distinct social domains.

RESULTS

A series of categorical and dimensional analyses revealed an association between inter-individual differences in HRV and inter-individual differences in psychosocial stress: Individuals with high HRV reported less stress in social life, but not in family life, work life or everyday life, than individuals with low HRV.

CONCLUSIONS

On basis of these findings, it may be assumed that individuals with high HRV experience less psychosocial stress than individuals with low HRV. Although such an assumption needs to be corroborated by further findings, it seems to be consistent with previous findings showing that individuals with high HRV suffer less from stress and stress-related disorders than individuals with low HRV.

Brain-to-brain coupling during handholding is associated with pain reduction

The mechanisms underlying analgesia related to social touch are not clear. While recent research highlights the role of the empathy of the observer to pain relief in the target, the contribution of social interaction to analgesia is unknown. The current study examines brain-to-brain coupling during pain with interpersonal touch and tests the involvement of interbrain synchrony in pain alleviation. Romantic partners were assigned the roles of target (pain receiver) and observer (pain observer) under pain-no-pain and touch-no-touch conditions concurrent with EEG recording. Brain-to-brain coupling in alpha-mu band (8-12 Hz) was estimated by a three-step multilevel analysis procedure based on running window circular correlation coefficient and post hoc power of the findings was calculated using simulations. Our findings indicate that hand-holding during pain administration increases brain-to-brain coupling in a network that mainly involves the central regions of the pain target and the right hemisphere of the pain observer. Moreover, brain-to-brain coupling in this network was found to correlate with analgesia magnitude and observer's empathic accuracy. These findings indicate that brain-to-brain coupling may be involved in touch-related analgesia.

Cognition, emotion and reward networks associated with sex differences for romantic appraisals

Romantic love is a cross-culturally universal phenomenon that serves as a commitment device for motivating pair bonding in human beings. Women and men may experience different feelings when viewing the same warm, romantic scenes. To determine which brain systems may be involved in romance perception and examine possible sex differences, we scanned 16 women and 16 men who were intensely in love, using functional MRI. Participants were required to rate the romance level of 60 pictures showing romantic events that may frequently occur during romantic relationship formation. The results showed that greater brain activation was found for men in the insula, PCC (posterior cingulate cortex), and prefrontal gyrus compared with women, primarily under the High-romance condition. In addition, enhanced functional connectivity between the brain regions involved in the High-romance condition in contrast to the Low-romance condition was only found for men. These data suggest that men and women differ in the processing of romantic information and that it may be  more effortful for men to perceive and evaluate romance degree.

Orbitofrontal cortex mediates pain inhibition by monetary reward

Pleasurable stimuli, including reward, inhibit pain, but the level of the neuraxis at which they do so and the cerebral processes involved are unknown. Here, we characterized a brain circuitry mediating pain inhibition by reward. Twenty-four healthy participants underwent functional magnetic resonance imaging while playing a wheel of fortune game with simultaneous thermal pain stimuli and monetary wins or losses. As expected, winning decreased pain perception compared to losing. Inter-individual differences in pain modulation by monetary wins relative to losses correlated with activation in the medial orbitofrontal cortex (mOFC). When pain and reward occured simultaneously, mOFCs functional connectivity changed: the signal time course in the mOFC condition-dependent correlated negatively with the signal time courses in the rostral anterior insula, anterior-dorsal cingulate cortex and primary somatosensory cortex, which might signify moment-to-moment down-regulation of these regions by the mOFC. Monetary wins and losses did not change the magnitude of pain-related activation, including in regions that code perceived pain intensity when nociceptive input varies and/or receive direct nociceptive input. Pain inhibition by reward appears to involve brain regions not typically involved in nociceptive intensity coding but likely mediate changes in the significance and/or value of pain.

Partner Loss in Monogamous Rodents: Modulation of Pain and Emotional Behavior in Male Prairie Voles

OBJECTIVE

Pain is modulated by psychosocial factors, and social stress-induced hyperalgesia is a common clinical symptom in pain disorders. To provide a new animal model for studying social modulation of pain, we examined pain behaviors in monogamous prairie voles experiencing partner loss.

METHODS

After cohabitation with novel females, males (n = 79) were divided into two groups on the basis of preference test scores. Half of the males of each group were separated from their partner (loss group), whereas the other half remained paired (paired group). Thus, males from both groups experienced social isolation. Open field tests, plantar tests, and formalin tests were then conducted on males to assess anxiety and pain-related behaviors.

RESULTS

Loss males showing partner preferences (n = 20) displayed a significant increase in anxiety-related behavior in the open-field test (central area/total distance: 13.65% [1.58%] for paired versus 6.45% [0.87%] for loss; p < .001), a low threshold of thermal stimulus in the plantar test (withdrawal latencies: 9.69 [0.98] seconds for paired versus 6.15 [0.75] seconds for loss; p = .037), and exacerbated pain behaviors in the formalin test (total number of lifts: 40.33 [4.46] for paired versus 54.42 [1.91] for loss; p = .042) as compared with paired males (n = 20). Thermal thresholds in the plantar test significantly correlated with anxiety-related behavior in the open-field test (r = 0.64). No such differences were observed in the males that did not display partner preferences (r = 0.15).

CONCLUSIONS

Results indicate that social bonds and their disruption, but not social housing without bonding followed by isolation, modulate pain and emotion in male prairie voles. The prairie vole is a useful model for exploring the neural mechanisms by which social relationships contribute to pain and nociceptive processing in humans.

The Social Regulation of Pain: Autonomic and Neurophysiological Changes Associated With Perceived Threat

The analgesic effect of social support is proposed as a function of social support modulating perceived threat of painful stimuli. In the current study, we directly examined the social buffering effect in the context of the threat of pain. Eighteen healthy participants were subjected to the threat of pain while they held the hand of a close other, a stranger, or not at all. Neural and autonomic responses were recorded using electroencephalogram and heart rate, respectively. Close other hand-holding reduced pain perception. This was accompanied by decreased heart rate and frontal theta oscillation (4-8 Hz) during the threat phase preceding painful stimulation. Interestingly, decreased heart rate and frontal theta in the close other hand-holding condition were uniquely associated with greater pain reduction during subsequent nociceptive stimulation. Neural changes were source-localized to the insular cortex and the rostral-ventral portions of anterior cingulate cortex, regions involved in the processing of threat and pain. Together, our data build upon work to date linking social support to pain by showing autonomic and neurophysiological changes associated with pain reduction.

PERSPECTIVE

Social support may reduce pain through buffering the autonomic and neurophysiological response to the threatening quality of noxious stimuli. Results implicate that in clinical settings the caregiver could help people with chronic pain reappraise pain and related conditions as less stressful.

The soothing function of touch: affective touch reduces feelings of social exclusion

The mammalian need for social proximity, attachment and belonging may have an adaptive and evolutionary value in terms of survival and reproductive success. Consequently, ostracism may induce strong negative feelings of social exclusion. Recent studies suggest that slow, affective touch, which is mediated by a separate, specific C tactile neurophysiological system than faster, neutral touch, modulates the perception of physical pain. However, it remains unknown whether slow, affective touch, can also reduce feelings of social exclusion, a form of social pain. Here, we employed a social exclusion paradigm, namely the Cyberball task (N = 84), to examine whether the administration of slow, affective touch may reduce the negative feelings of ostracism induced by the social exclusion manipulations of the Cyberball task. As predicted, the provision of slow-affective, as compared to fast-neutral, touch led to a specific decrease in feelings of social exclusion, beyond general mood effects. These findings point to the soothing function of slow, affective touch, particularly in the context of social separation or rejection, and suggest a specific relation between affective touch and social bonding.

Relationship status and perceived support in the social regulation of neural responses to threat

Strong social ties correspond with better health and well being, but the neural mechanisms linking social contact to health remain speculative. This study extends work on the social regulation of brain activity by supportive handholding in 110 participants (51 female) of diverse racial and socioeconomic origins. In addition to main effects of social regulation by handholding, we assessed the moderating effects of both perceived social support and relationship status (married, cohabiting, dating or platonic friends). Results suggest that, under threat of shock, handholding by familiar relational partners attenuates both subjective distress and activity in a network associated with salience, vigilance and regulatory self-control. Moreover, greater perceived social support corresponded with less brain activity in an extended network associated with similar processes, but only during partner handholding. In contrast, we did not observe any regulatory effects of handholding by strangers, and relationship status did not moderate the regulatory effects of partner handholding. These findings suggest that contact with a familiar relational partner is likely to attenuate subjective distress and a variety of neural responses associated with the presence of threat. This effect is likely enhanced by an individual's expectation of the availability of support from their wider social network.

Uncovering the influence of social skills and psychosociological factors on pain sensitivity using structural equation modeling

Pain is a subjective emotional experience that is influenced by psychosociological factors such as social skills, which are defined as problem-solving abilities in social interactions. This study aimed to reveal the relationships among pain, social skills, and other psychosociological factors by using structural equation modeling. A total of 101 healthy volunteers (41 men and 60 women; mean age: 36.6±12.7 years) participated in this study. To evoke participants’ sense of inner pain, we showed them images of painful scenes on a PC screen and asked them to evaluate the pain intensity by using the visual analog scale (VAS). We examined the correlation between social skills and VAS, constructed a hypothetical model based on results from previous studies and the current correlational analysis results, and verified the model’s fit using structural equation modeling. We found significant positive correlations between VAS and total social skills values, as well as between VAS and the “start of relationships” subscales. Structural equation modeling revealed that the values for “start of relationships” had a direct effect on VAS values (path coefficient =0.32, p<0.01). In addition, the “start of relationships” had both a direct and an indirect effect on psychological factors via social support. The results indicated that extroverted people are more sensitive to inner pain and tend to get more social support and maintain a better psychological condition.