Separate neural representations for physical pain and social rejection

Large-scale Meta-analysis Suggests Low Regional Modularity in Lateral Frontal Cortex

Extensive fMRI study of human lateral frontal cortex (LFC) has yet to yield a consensus mapping between discrete anatomy and psychological states, partly due to the difficulty of inferring mental states from brain activity. Despite this, there have been few large-scale efforts to map the full range of psychological states across the entirety of LFC. Here, we used a data-driven approach to generate a comprehensive functional-anatomical mapping of LFC from 11 406 neuroimaging studies. We identified putatively separable LFC regions on the basis of whole-brain co-activation, revealing 14 clusters organized into 3 whole-brain networks. Next, we generated functional preference profiles by using multivariate classification to identify the psychological states that best predicted activity within each cluster. We observed large functional differences between networks, suggesting brain networks support distinct modes of processing. Within each network, however, we observed relatively low functional specificity, suggesting discrete psychological states are not strongly localized to individual regions; instead, our results are consistent with the view that individual LFC regions work as part of distributed networks to give rise to flexible behavior. Collectively, our results provide a comprehensive synthesis of a diverse neuroimaging literature using relatively unbiased data-driven methods.

A Guide to Representational Similarity Analysis for Social Neuroscience

Representational similarity analysis (RSA) is a computational technique that uses pairwise comparisons of stimuli to reveal their representation in higher-order space. In the context of neuroimaging, mass-univariate analyses and other multivariate analyses can provide information on what and where information is represented but have limitations in their ability to address how information is represented. Social neuroscience is a field that can particularly benefit from incorporating RSA techniques to explore hypotheses regarding the representation of multidimensional data, how representations can predict behavior, how representations differ between groups and how multimodal data can be compared to inform theories. The goal of this paper is to provide a practical as well as theoretical guide to implementing RSA in social neuroscience studies.

Out of the dark, into the light: The impact of social exclusion on judgments of darkness and brightness

Based on theories of grounded cognition, we assumed that the experience of social exclusion is grounded in a concept of darkness. Specifically, we hypothesized that social exclusion causes perceptual judgments of darkness and a preference for brightness as a compensatory response. To investigate these hypotheses, we conducted four studies using different manipulations and measurements. In Studies 1a and 1b, excluded participants judged a picturized room as darker and drew more attention to its brightest part than included participants. In Study 2, excluded participants judged a surface as darker and decided for brighter clothing than included participants. In Study 3, excluded participants judged their lab room as darker and expressed a higher preference for brightness than included participants. Providing consistent support for our hypotheses, these findings confirm the idea that the experience of social exclusion is grounded in multiple ways that share a common representational system.

The role of hedonics in the Human Affectome

Experiencing pleasure and displeasure is a fundamental part of life. Hedonics guide behavior, affect decision-making, induce learning, and much more. As the positive and negative valence of feelings, hedonics are core processes that accompany emotion, motivation, and bodily states. Here, the affective neuroscience of pleasure and displeasure that has largely focused on the investigation of reward and pain processing, is reviewed. We describe the neurobiological systems of hedonics and factors that modulate hedonic experiences (e.g., cognition, learning, sensory input). Further, we review maladaptive and adaptive pleasure and displeasure functions in mental disorders and well-being, as well as the experience of aesthetics. As a centerpiece of the Human Affectome Project, language used to express pleasure and displeasure was also analyzed, and showed that most of these analyzed words overlap with expressions of emotions, actions, and bodily states. Our review shows that hedonics are typically investigated as processes that accompany other functions, but the mechanisms of hedonics (as core processes) have not been fully elucidated.

Neuroimaging-based biomarkers for pain: state of the field and current directions

Chronic pain is an endemic problem involving both peripheral and brain pathophysiology. Although biomarkers have revolutionized many areas of medicine, biomarkers for pain have remained controversial and relatively underdeveloped. With the realization that biomarkers can reveal pain-causing mechanisms of disease in brain circuits and in the periphery, this situation is poised to change. In particular, brain pathophysiology may be diagnosable with human brain imaging, particularly when imaging is combined with machine learning techniques designed to identify predictive measures embedded in complex data sets. In this review, we explicate the need for brain-based biomarkers for pain, some of their potential uses, and some of the most popular machine learning approaches that have been brought to bear. Then, we evaluate the current state of pain biomarkers developed with several commonly used methods, including structural magnetic resonance imaging, functional magnetic resonance imaging and electroencephalography. The field is in the early stages of biomarker development, but these complementary methodologies have already produced some encouraging predictive models that must be tested more extensively across laboratories and clinical populations.

Feeling Hurt: Revisiting the Relationship Between Social and Physical Pain

Pain overlap theory has generated decades of controversy and still receives considerable research attention. A major advance has been the revelation that social and physical pain activate similar neural regions, providing suggestive evidence of a “piggybacked” alarm system that coevolved to detect social exclusion. Recent developments, however, have brought neural evidence for pain overlap into question. We analyze these developments from a social psychological perspective and identify the need for a reformulated approach. To meet this need, we provide a framework that a priori predicts generalized overlap and specific divergence across a range of biopsychosocial domains. The framework points to a functional pattern for similarities and differences, which can be utilized to generate testable hypotheses so that the field can move forward. To demonstrate the utility and promise of the framework, we identify key hypotheses relating to attention, motivation, and responses to pain, and review research relevant to these hypotheses.

Variation in the μ-Opioid Receptor Gene (OPRM1) Does Not Moderate Social-Rejection Sensitivity in Humans

Given previous findings from animal studies and small-scale studies in humans, variation in the μ-opioid receptor gene ( OPRM1) has been proposed as a strong biological candidate for moderating sensitivity to social rejection. Using a substantially larger sample ( N = 490) than previous studies, a prospective genotyping strategy, and preregistered analysis plans, we tested the hypotheses that OPRM1 variation measured by the functional A118G polymorphism (rs1799971) moderates (a) dispositional sensitivity to rejection and feelings of distress following social exclusion and (b) decision making involving social cognition. In three experimental tasks commonly used to assess altruism, reciprocity, and trust in humans, we found no evidence in favor of the hypotheses; nine main tests were preregistered, and all of them yielded small and statistically insignificant estimates. In secondary analyses, we used Bayesian inference and estimation to quantify support for our findings. Taken together, our results strongly suggest that the link between OPRM1 A118G variation and social-rejection sensitivity is weaker than previously thought.

Age-Normative Pathways of Striatal Connectivity Related to Clinical Symptoms in the General Population

BACKGROUND

Altered striatal development contributes to core deficits in motor and inhibitory control, impulsivity, and inattention associated with attention-deficit/hyperactivity disorder and may likewise play a role in deficient reward processing and emotion regulation in psychosis and depression. The maturation of striatal connectivity has not been well characterized, particularly as it relates to clinical symptomatology.

METHODS

Resting-state functional connectivity with striatal subdivisions was examined for 926 participants (8-22 years of age, 44% male) from the general population who had participated in two large cross-sectional studies. Developing circuits were identified and growth charting of age-related connections was performed to obtain individual scores reflecting relative neurodevelopmental attainment. Associations of clinical symptom scales (attention-deficit/hyperactivity disorder, psychosis, depression, and general psychopathology) with the resulting striatal connectivity age-deviation scores were then tested using elastic net regression.

RESULTS

Linear and nonlinear developmental patterns occurred across 231 striatal age-related connections. Both unique and overlapping striatal age-related connections were associated with the four symptom domains. Attention-deficit/hyperactivity disorder severity was related to age-advanced connectivity across several insula subregions, but to age-delayed connectivity with the nearby inferior frontal gyrus. Psychosis was associated with advanced connectivity with the medial prefrontal cortex and superior temporal gyrus, while aberrant limbic connectivity predicted depression. The dorsal posterior insula, a region involved in pain processing, emerged as a strong contributor to general psychopathology as well as to each individual symptom domain.

CONCLUSIONS

Developmental striatal pathophysiology in the general population is consistent with dysfunctional circuitry commonly found in clinical populations. Atypical age-normative connectivity may thereby reflect aberrant neurodevelopmental processes that contribute to clinical risk.

Spatial Patterns of Brain Activity Preferentially Reflecting Transient Pain and Stimulus Intensity

How pain emerges in the human brain remains an unresolved question. Neuroimaging studies have suggested that several brain areas subserve pain perception because their activation correlates with perceived pain intensity. However, painful stimuli are often intense and highly salient; therefore, using both intensity- and saliency-matched control stimuli is crucial to isolate pain-selective brain responses. Here, we used these intensity/saliency-matched painful and non-painful stimuli to test whether pain-selective information can be isolated in the functional magnetic resonance imaging responses elicited by painful stimuli. Using two independent datasets, multivariate pattern analysis was able to isolate features distinguishing the responses triggered by (1) intensity/saliency-matched painful versus non-painful stimuli, and (2) high versus low-intensity/saliency stimuli regardless of whether they elicit pain. This indicates that neural activity in the so-called "pain matrix" is functionally heterogeneous, and part of it carries information related to both painfulness and intensity/saliency. The response features distinguishing these aspects are spatially distributed and cannot be ascribed to specific brain structures.

False-positive neuroimaging: Undisclosed flexibility in testing spatial hypotheses allows presenting anything as a replicated finding

Hypothesis testing in neuroimaging studies relies heavily on treating named anatomical regions (e.g., "the amygdala") as unitary entities. Though data collection and analyses are conducted at the voxel level, inferences are often based on anatomical regions. The discrepancy between the unit of analysis and the unit of inference leads to ambiguity and flexibility in analyses that can create a false sense of reproducibility. For example, hypothesizing effects on "amygdala activity" does not provide a falsifiable and reproducible definition of precisely which voxels or which patterns of activation should be observed. Rather, it comprises a large number of unspecified sub-hypotheses, leaving room for flexible interpretation of findings, which we refer to as "model degrees of freedom." From a survey of 135 functional Magnetic Resonance Imaging studies in which researchers claimed replications of previous findings, we found that 42.2% of the studies did not report any quantitative evidence for replication such as activation peaks. Only 14.1% of the papers used exact coordinate-based or a priori pattern-based models. Of the studies that reported peak information, 42.9% of the 'replicated' findings had peak coordinates more than 15 mm away from the 'original' findings, suggesting that different brain locations were activated, even when studies claimed to replicate prior results. To reduce the flexible and qualitative region-level tests in neuroimaging studies, we recommend adopting quantitative spatial models and tests to assess the spatial reproducibility of findings. Techniques reviewed here include permutation tests on peak distance, Bayesian MANOVA, and a priori multivariate pattern-based models. These practices will help researchers to establish precise and falsifiable spatial hypotheses, promoting a cumulative science of neuroimaging.

Composite Pain Biomarker Signatures for Objective Assessment and Effective Treatment

Pain is a subjective sensory experience that can, mostly, be reported but cannot be directly measured or quantified. Nevertheless, a suite of biomarkers related to mechanisms, neural activity, and susceptibility offer the possibility-especially when used in combination-to produce objective pain-related indicators with the specificity and sensitivity required for diagnosis and for evaluation of risk of developing pain and of analgesic efficacy. Such composite biomarkers will also provide improved understanding of pain pathophysiology.

Psychological Manifestations and Chronic Pain in Whiplash-Associated Disorder Mechanisms: The Whole Pie, Please

In the last decade, as the biopsychosocial model of patient health care has expanded, there has been an increased focus on the influence of psychological manifestations on patient symptoms and health-related outcomes. This Viewpoint explores the scientific underpinnings of psychological manifestations in chronic whiplash-associated disorders (WADs)-where opinions vary widely concerning the reason for persistent symptoms and nonrecovery. It also provides an epidemiological and scientific foundation for the management of chronic WAD, incorporating the spectrum of the biopsychosocial model. J Orthop Sports Phys Ther 2019;49(3):118-121. doi:10.2519/jospt.2019.0603.

The gut-brain axis in health neuroscience: implications for functional gastrointestinal disorders and appetite regulation

Over the past few years, scientific interest in the gut-brain axis (i.e., the bidirectional communication system between the gastrointestinal tract and the brain) has exploded, mostly due to the identification of the gut microbiota as a novel key player in this communication. However, important progress has also been made in other aspects of gut-brain axis research, which has been relatively underemphasized in the review literature. Therefore, in this review, we provide a comprehensive, although not exhaustive, overview of recent research on the functional neuroanatomy of the gut-brain axis and its relevance toward the multidisciplinary field of health neuroscience, excluding studies on the role of the gut microbiota. More specifically, we first focus on irritable bowel syndrome, after which we outline recent findings on the role of the gut-brain axis in appetite and feeding regulation, primarily focusing on the impact of subliminal nutrient-related gut-brain signals. We conclude by providing future perspectives to facilitate translation of the findings from gut-brain axis neuroscientific research to clinical applications in these domains.

Non-medical prescription opioid users exhibit dysfunctional physiological stress responses to social rejection

Non-medical prescription opioid use (NMPOU) recently increased dramatically, especially in the U.S. Although chronic opioid use is commonly accompanied by deficits in social functioning and dysregulation of the hypothalamic-pituitary adrenergic (HPA) stress axis, little is known about the impact of NMPOU on psychosocial stress responses. Therefore, we measured physiological responses of the autonomic nervous system and the HPA axis to social rejection using the Cyberball paradigm. We compared 23 individuals with NMPOU, objectively confirmed by hair and urine analyses, with 29 opioid-naïve, healthy controls. As expected, heart rate variability (HRV), an index of parasympathetic activity, increased significantly during exclusion within controls, while in the NMPOU group only a trend in the same direction was found. However, increased HRV was robustly moderated by opioid craving indicating worse emotion regulation to social exclusion specifically in individuals with high opioid craving. Greater levels of the adrenocorticotropic hormone and cortisol responses to social rejection were found in the NMPOU group indicating hyperreactivity of the HPA axis to social exclusion. Self-ratings suggest that opioid users were aware of rejection, but less emotionally affected by exclusion. Furthermore, controls showed greater negative mood after the Cyberball confirming the task's validity. Moreover, NMPOU individuals reported a smaller social network size compared to controls. Present findings suggest that chronic NMPOU is associated with dysfunctional physiological responses to psychosocial stressors such as social rejection. In sum, NMPOU was associated with poorer regulation of the parasympathetic nervous system, especially under opioid craving highlighting its potential importance in relapse prevention.

Neural substrates for moral judgments of psychological versus physical harm

While we may think about harm as primarily being about physical injury, harm can also take the form of negative psychological impact. Using functional magnetic resonance imaging, we examined the extent to which moral judgments of physical and psychological harms are processed similarly, focusing on brain regions implicated in mental state reasoning or theory of mind, a key cognitive process for moral judgment. First, univariate analyses reveal item-specific features that lead to greater recruitment of theory of mind regions for psychological harm versus physical harm. Second, multivariate pattern analyses reveal sensitivity to the psychological/physical distinction in two regions implicated in theory of mind: the right temporoparietal junction and the precuneus. Third, we find no reliable differences between neurotypical adults and adults with autism spectrum disorder with regard to neural activity related to theory of mind during moral evaluations of psychological and physical harm. Altogether, these results reveal neural sensitivity to the distinction between psychological harm and physical harm.

Default mode network can support the level of detail in experience during active task states

Accounts of the default mode network (DMN) as task negative are partly based on evidence for a role of this system in off-task thought. We revisited the evidence for this assumption in a study combining experience sampling with functional neuroimaging. Whether thoughts were related or unrelated to an ongoing task was associated with patterns of neural activity in regions adjacent to unimodal sensorimotor cortex. In contrast, during periods of working-memory maintenance, activity patterns in the DMN were associated with whether thoughts were detailed. These results demonstrate that activity within the DMN encodes information associated with ongoing cognition that goes beyond whether attention is directed to the task, including detailed experiences during active task states.

Regions of transmodal cortex, in particular the default mode network (DMN), have historically been argued to serve functions unrelated to task performance, in part because of associations with naturally occurring periods of off-task thought. In contrast, contemporary views of the DMN suggest it plays an integrative role in cognition that emerges from its location at the top of a cortical hierarchy and its relative isolation from systems directly involved in perception and action. The combination of these topographical features may allow the DMN to support abstract representations derived from lower levels in the hierarchy and so reflect the broader cognitive landscape. To investigate these contrasting views of DMN function, we sampled experience as participants performed tasks varying in their working-memory load while inside an fMRI scanner. We used self-report data to establish dimensions of thought that describe levels of detail, the relationship to a task, the modality of thought, and its emotional qualities. We used representational similarity analysis to examine correspondences between patterns of neural activity and each dimension of thought. Our results were inconsistent with a task-negative view of DMN function. Distinctions between on- and off-task thought were associated with patterns of consistent neural activity in regions adjacent to unimodal cortex, including motor and premotor cortex. Detail in ongoing thought was associated with patterns of activity within the DMN during periods of working-memory maintenance. These results demonstrate a contribution of the DMN to ongoing cognition extending beyond task-unrelated processing that can include detailed experiences occurring under active task conditions.

Distinguishing neural correlates of context-dependent advantageous- and disadvantageous-inequity aversion

Humans can integrate social contextual information into decision-making processes to adjust their responses toward inequity. This context dependency emerges when individuals receive more (i.e., advantageous inequity) or less (i.e., disadvantageous inequity) than others. However, it is not clear whether context-dependent processing of advantageous and disadvantageous inequity involves differential neurocognitive mechanisms. Here, we used fMRI to address this question by combining an interactive game that modulates social contexts (e.g., interpersonal guilt) with computational models that enable us to characterize individual weights on inequity aversion. In each round, the participant played a dot estimation task with an anonymous coplayer. The coplayer would receive pain stimulation with 50% probability when either of them responded incorrectly. At the end of each round, the participant completed a variant of dictator game, which determined payoffs for him/herself and the coplayer. Computational modeling demonstrated the context dependency of inequity aversion: when causing pain to the coplayer (i.e., guilt context), participants cared more about the advantageous inequity and became more tolerant of the disadvantageous inequity, compared with other conditions. Consistently, neuroimaging results suggested the two types of inequity were associated with differential neurocognitive substrates. While the context-dependent processing of advantageous inequity was associated with social- and mentalizing-related processes, involving left anterior insula, right dorsolateral prefrontal cortex, and dorsomedial prefrontal cortex, the context-dependent processing of disadvantageous inequity was primarily associated with emotion- and conflict-related processes, involving left posterior insula, right amygdala, and dorsal anterior cingulate cortex. These results extend our understanding of decision-making processes related to inequity aversion.

Beyond unpleasantness. Social exclusion affects the experience of pain, but not of equally-unpleasant disgust

Seminal theories posit that social and physical suffering underlie partly-common representational code. It is unclear, however, if this shared information reflects a modality-specific component of pain, or alternatively a supramodal code for properties common to many aversive experiences (unpleasantness, salience, etc.). To address this issue, we engaged participants in a gaming experience in which they were excluded or included by virtual players. After each game session, participants were subjected to comparably-unpleasant painful or disgusting stimuli. Subjective reports and cardiac responses revealed a reduced sensitivity to pain following exclusion relative to inclusion, an effect which was more pronounced in those participants who declared to feel more affected by the gaming manipulation. Such modulation was not observed for disgust. These findings indicate that the relationship between social and physical suffering does not generalize to disgust, thus suggesting a shared representational code at the level of modality-specific components of pain.

Comparing task-induced psychophysiological responses between persons with stress-related complaints and healthy controls: A methodological pilot study

AIMS

Chronic stress is an important factor for a variety of health problems, highlighting the importance of early detection of stress-related problems. This methodological pilot study investigated whether the physiological response to and recovery from a stress task can differentiate healthy participants and persons with stress-related complaints.

METHODS AND RESULTS

Healthy participants (n = 20) and participants with stress-related complaints (n = 12) participated in a laboratory stress test, which included 3 stress tasks. Three physiological signals were recorded: galvanic skin response (GSR), heart rate (HR), and skin temperature (ST). From these signals, 126 features were extracted, including static (eg, mean) and dynamic (eg, recovery time) features. Unsupervised feature selection reduced the set to 26 features. A logistic regression model was developed for 6 feature sets, analysing single-parameter and multiparameter models as well as models using recovery vs response-related features. The highest classification performance (accuracy = 78%) was obtained using the response-related feature set, including all physiological signals and using GSR-related features. A worse performance was obtained using single-signal feature sets based on HR (accuracy = 66%) and ST (accuracy = 59%). Response-related features outperformed recovery-related features (accuracy = 63%).

CONCLUSION

Participants with stress-related complaints may be differentiated from healthy controls by physiological responses to stress tasks. We aimed to bring attention to new exploratory methodologies; further research is needed to validate and replicate the results on larger populations and patients on different areas along the stress continuum.

Presence of an Attachment Figure Is Associated With Greater Sensitivity to Physical Pain Following Mild Social Exclusion

Social exclusion has been shown to influence sensitivity to physical pain. Attachment theory suggests a primary response to rejection should be seeking out the company of a close other. Based on this prediction, we hypothesized that the presence of an attachment figure versus a stranger following rejection would permit acknowledgement of distress and thus stronger reports of physical pain. Healthy participants reported their pain sensitivity before receiving exclusion or inclusion feedback in an online chat. Participants were then randomly assigned to have access to their attachment figure or a stranger and had pain sensitivity measured again. As predicted, excluded participants who had access to their attachment figure evidenced heightened pain sensitivity (lower pain threshold and tolerance), whereas those who sat with a stranger evidenced some degree of a decrease in pain sensitivity (higher pain tolerance). These data may shed light on the impact social ties can have during painful situations.

Neural Population Decoding Reveals the Intrinsic Positivity of the Self

People are motivated to hold favorable views of themselves, which manifests as a positivity bias when evaluating their own performance and abilities. However, it remains an open question whether positive affect is an essential component of people's self-concept. Prior functional neuroimaging research demonstrated that similar regions of the brain support positive affect and self-referential processing, although a direct test of their shared representation has yet to be examined. Here we use functional magnetic resonance imaging in conjunction with multivariate pattern analysis in a cross-domain neural population decoding paradigm. We found that a multivariate pattern classifier model trained to dissociate neural responses to viewing positively and negatively valenced images can dissociate thinking about oneself from a close friend during a lexical trait-judgment task commonly used in the study of self-referential processing. Cross-domain classification accuracy was found to be highest in the ventral medial prefrontal cortex (vMPFC), a region previously implicated in both self-referential processing and positive affect. These results show that brain responses during self-referential processing can be decoded from multi-voxel activation patterns in the vMPFC when viewing positively valenced material, thereby providing evidence that positive affect may be a central component of the mental representation of the self.

Evolution of Structural DNA Nanotechnology

The research field entitled structural DNA nanotechnology emerged in the beginning of the 1980s as the first immobile synthetic nucleic acid junctions were postulated and demonstrated. Since then, the field has taken huge leaps toward advanced applications, especially during the past decade. This Progress Report summarizes how the controllable, custom, and accurate nanostructures have recently evolved together with powerful design and simulation software. Simultaneously they have provided a significant expansion of the shape space of the nanostructures. Today, researchers can select the most suitable fabrication methods, and design paradigms and software from a variety of options when creating unique DNA nanoobjects and shapes for a plethora of implementations in materials science, optics, plasmonics, molecular patterning, and nanomedicine.

A common neural code for social and monetary rewards in the human striatum

Although managing social information and decision making on the basis of reward is critical for survival, it remains uncertain whether differing reward type is processed in a uniform manner. Previously, we demonstrated that monetary reward and the social reward of good reputation activated the same striatal regions including the caudate nucleus and putamen. However, it remains unclear whether overlapping activations reflect activities of identical neuronal populations or two overlapping but functionally independent neuronal populations. Here, we re-analyzed the original data and addressed this question using multivariate-pattern-analysis and found evidence that in the left caudate nucleus and bilateral nucleus accumbens, social vs monetary reward were represented similarly. The findings suggest that social and monetary rewards are processed by the same population of neurons within these regions of the striatum. Additional findings demonstrated similar neural patterns when participants experience high social reward compared to viewing others receiving low social reward (potentially inducing schadenfreude). This is possibly an early indication that the same population of neurons may be responsible for processing two different types of social reward (good reputation and schadenfreude). These findings provide a supplementary perspective to previous research, helping to further elucidate the mechanisms behind social vs non-social reward processing.

Decomposing Gratitude: Representation and Integration of Cognitive Antecedents of Gratitude in the Brain

Gratitude is a typical social-moral emotion that plays a crucial role in maintaining human cooperative interpersonal relationship. Although neural correlates of gratitude have been investigated, the neurocognitive processes that lead to gratitude, namely, the representation and integration of its cognitive antecedents, remain largely unknown. Here, we combined fMRI and a human social interactive task to investigate how benefactor's cost and beneficiary's benefit, two critical antecedents of gratitude, are encoded and integrated in beneficiary's brain, and how the neural processing of gratitude is converted to reciprocity. A coplayer decided whether to help a human participant (either male or female) avoid pain at his/her own monetary cost; the participants could transfer monetary points to the benefactor with the knowledge that the benefactor was unaware of this transfer. By independently manipulating monetary cost and the degree of pain reduction, we could identify the neural signatures of benefactor's cost and recipient's benefit and examine how they were integrated. Recipient's self-benefit was encoded in reward-sensitive regions (e.g., ventral striatum), whereas benefactor-cost was encoded in regions associated with mentalizing (e.g., temporoparietal junction). Gratitude was represented in perigenual anterior cingulate cortex (pgACC), the strength of which correlated with trait gratitude. Dynamic causal modeling showed that the neural signals representing benefactor-cost and self-benefit passed to pgACC via effective connectivities, suggesting an integrative role of pgACC in generating gratitude. Moreover, gyral ACC plays an intermediary role in converting gratitude representation into reciprocal behaviors. Our findings provide a neural mechanistic account of gratitude and its role in social-moral life.SIGNIFICANCE STATEMENT Gratitude plays an integral role in subjective well-being and harmonious interpersonal relationships. However, the neurocognitive processes through which various components and antecedents of gratitude are integrated remain largely unknown. We developed a new interpersonal paradigm to independently and parametrically manipulate two antecedents of gratitude in a helping context, namely, the benefit to beneficiary and the cost to benefactor, to examine their representation and integration in the beneficiary's brain using fMRI. We found the neural encoding of self-benefit and benefactor-cost in reward- and mentalizing-related brain areas, respectively. More importantly, by examining effective connectivity, we showed that these componential signals are passed to perigenual anterior cingulate cortex, which tracks trial-by-trial gratitude levels. Our study thus provides a neural mechanistic account of gratitude.

The salience of self, not social pain, is encoded by dorsal anterior cingulate and insula

The human neural correlates of social rejection have attracted significant research interest, but remain subject to vigorous debate. Specifically, it has been proposed that a matrix of brain regions overlapping with the classical pain matrix, and including the dorsal anterior cingulate cortex (dACC) and the anterior insular cortex (AI) is critical for processing of social rejection. The present study expands on this conceptualization, by showing that these areas are involved in processing of self-relevant social evaluation, irrespective of valence. Forty healthy adolescents (N = 20 females) were tested in a magnetic resonance imaging (MRI) scanner. We used a novel paradigm that balanced participants' experience of rejection and acceptance. In addition, the paradigm also controlled for whether the social judgment was towards the participants or towards other fictitious players. By creating a "self" and "other" distinction, we show that right AI and dACC are involved in processing the salience of being judged by others, irrespective of the quality of this judgment. This finding supports the idea that these regions are not specific to social rejection or even to pain or metaphorically painful experiences, but activate to self-relevant, highly salient information.

Interkulturelle Unterschiede im Erleben und Verhalten nach sozialer Exkludierung

Zusammenfassung. Soziale Exkludierung, von anderen entfernt gehalten zu werden, zieht schwerwiegende psychische und physische Reaktionen nach sich. Wie stark allerdings Menschen von sozialer Exkludierung bedroht sind, hängt von verschiedenen Faktoren ab. Im vorliegenden Forschungsartikel wird der Frage nachgegangen, inwiefern kulturelle Unterschiede das Erleben sozialer Exkludierung beeinflussen. Die aktuelle Forschung zeigt, dass Personen mit kollektivistischem Hintergrund von Exkludierung weniger psychologisch beeinträchtigt sind als Personen mit individualistischem Hintergrund, weil sie als weniger bedrohlich und destabilisierend wahrgenommen wird. Neben der Darstellung empirischer Befunde werden die Grenzen des Effekts diskutiert, sowie theoretische und praktische Implikationen vorgestellt.

Pain Neuroimaging in Humans: A Primer for Beginners and Non-Imagers

Human pain neuroimaging has exploded in the past 2 decades. During this time, the broader neuroimaging community has continued to investigate and refine methods. Another key to progress is exchange with clinicians and pain scientists working with other model systems and approaches. These collaborative efforts require that non-imagers be able to evaluate and assess the evidence provided in these reports. Likewise, new trainees must design rigorous and reliable pain imaging experiments. In this article we provide a guideline for designing, reading, evaluating, analyzing, and reporting results of a pain neuroimaging experiment, with a focus on functional and structural magnetic resonance imaging. We focus in particular on considerations that are unique to neuroimaging studies of pain in humans, including study design and analysis, inferences that can be drawn from these studies, and the strengths and limitations of the approach.

Social comparison in the brain: A coordinate-based meta-analysis of functional brain imaging studies on the downward and upward comparisons

Social comparison is ubiquitous across human societies with dramatic influence on people's well-being and decision making. Downward comparison (comparing to worse-off others) and upward comparison (comparing to better-off others) constitute two types of social comparisons that produce different neuropsychological consequences. Based on studies exploring neural signatures associated with downward and upward comparisons, the current study utilized a coordinate-based meta-analysis to provide a refinement of understanding about the underlying neural architecture of social comparison. We identified consistent involvement of the ventral striatum and ventromedial prefrontal cortex in downward comparison and consistent involvement of the anterior insula and dorsal anterior cingulate cortex in upward comparison. These findings fit well with the "common-currency" hypothesis that neural representations of social gain or loss resemble those for non-social reward or loss processing. Accordingly, we discussed our findings in the framework of general reinforcement learning (RL) hypothesis, arguing how social gain/loss induced by social comparisons could be encoded by the brain as a domain-general signal (i.e., prediction errors) serving to adjust people's decisions in social settings. Although the RL account may serve as a heuristic framework for the future research, other plausible accounts on the neuropsychological mechanism of social comparison were also acknowledged. Hum Brain Mapp 39:440-458, 2018. © 2017 Wiley Periodicals, Inc.

The impact of social exclusion on anticipatory attentional processing

The importance of understanding how we anticipate and prepare for social rejection is underscored by the mental and physical toll of continual social vigilance. In this study, we investigate the impact of social rejection on anticipatory attentional processes using the well-known Cyberball task, a paradigm in which participants engage in a game of catch with virtual avatars who after an initial period of fair-play (inclusion condition) then exclude the participant from the game (exclusion condition). The degree of anticipatory attention allocated by subjects towards the avatars was assessed by measuring P3b responses towards the avatars' preparatory actions (i.e. the phase preceding their exclusionary actions) using high density EEG. The results of the study show that relative to the inclusion, participants exhibit elevated levels of anticipatory attentional allocation towards the avatars during the exclusion block. This shift was however significantly moderated by participants' self-reported cognitive regulation tendencies. Participants with higher levels of self-reported cognitive reappraisal tendencies showed larger anticipatory P3b increases from the inclusion to exclusion block relative to participants with reduced levels of reappraisal tendencies. These results highlight the impact of social exclusion on anticipatory neural processing and the moderating role of cognitive reappraisal on these effects.

Generalizable representations of pain, cognitive control, and negative emotion in medial frontal cortex

The medial frontal cortex (MFC), including anterior midcingulate cortex, has been linked to multiple psychological domains, including cognitive control, pain, and emotion. However, it is unclear whether this region encodes representations of these domains that are generalizable across studies and subdomains. Additionally, if there are generalizable representations, do they reflect a single underlying process shared across domains, or multiple domain-specific processes? We decomposed multivariate patterns of fMRI activity from 270 participants across 18 studies into study-specific, subdomain-specific, and domain-specific components, and identified latent multivariate representations that generalized across subdomains but were specific to each domain. Pain representations were localized to anterior midcingulate cortex, negative emotion representations to ventromedial prefrontal cortex, and cognitive control representations to portions of the dorsal midcingulate. These findings provide evidence for MFC representations that generalize across studies and subdomains, but are specific to distinct psychological domains rather than reducible to a single underlying process.

Reduced empathic responses for sexually objectified women: An fMRI investigation

Sexual objectification is a widespread phenomenon characterized by a focus on the individual's physical appearance over his/her mental state. This has been associated with negative social consequences, as objectified individuals are judged to be less human, competent, and moral. Moreover, behavioral responses toward the person change as a function of the degree of the perceived sexual objectification. In the present study, we investigated how behavioral and neural representations of other social pain are modulated by the degree of sexual objectification of the target. Using a within-subject fMRI design, we found reduced empathic feelings for positive (but not negative) emotions toward sexually objectified women as compared to non-objectified (personalized) women when witnessing their participation to a ball-tossing game. At the brain level, empathy for social exclusion of personalized women recruited areas coding the affective component of pain (i.e., anterior insula and cingulate cortex), the somatosensory components of pain (i.e., posterior insula and secondary somatosensory cortex) together with the mentalizing network (i.e., middle frontal cortex) to a greater extent than for the sexually objectified women. This diminished empathy is discussed in light of the gender-based violence that is afflicting the modern society.

Nicotine Abstinence Influences the Calculation of Salience in Discrete Insular Circuits

BACKGROUND

Insular subdivisions show distinct patterns of resting-state functional connectivity (rsFC) with specific brain regions, each with different functional significance. Seeds in these subdivisions are employed to characterize the effects of acute nicotine abstinence on rsFC between insula subdivisions and brain networks implicated in addiction and attentional control.

METHODS

In a within-subjects design, resting-state blood oxygen level-dependent data were collected from treatment-seeking smokers (N= 20) following smoking satiety and again following 48 hours of nicotine abstinence. Three right hemisphere insular regions of interest (dorsal, ventral, and posterior) served as seeds for analyses. Indices of both static and dynamic rsFC were obtained and correlated with indices of subjective withdrawal and behavioral performance.

RESULTS

Abstinence-induced physiological, subjective, and cognitive differences were observed. Overall dynamic rsFC was reduced during abstinence, and circuits containing each insular seed showed changes in rsFC as a function of nicotine abstinence. Specifically, dorsal and posterior insular connections to the default mode and salience networks were enhanced, while a previously undescribed ventral insular connection to the executive control network was reduced. Further, static rsFC was significantly correlated with subjective ratings of aversive affect and withdrawal in the modified ventral and posterior insular-seeded circuits.

CONCLUSIONS

As predicted, divergent connections between insula subdivisions and anticorrelated resting brain networks were observed during abstinence. These changes reflect an attentional bias toward aversive affective processing and not directly away from exogenous cognitive processing, suggesting a coordinated modulation of circuits associated with interoceptive and affective processing that instantiates an aversive state during nicotine abstinence.

Brain imaging tests for chronic pain: medical, legal and ethical issues and recommendations

Chronic pain is the greatest source of disability globally and claims related to chronic pain feature in many insurance and medico-legal cases. Brain imaging (for example, functional MRI, PET, EEG and magnetoencephalography) is widely considered to have potential for diagnosis, prognostication, and prediction of treatment outcome in patients with chronic pain. In this Consensus Statement, a presidential task force of the International Association for the Study of Pain examines the capabilities of brain imaging in the diagnosis of chronic pain, and the ethical and legal implications of its use in this way. The task force emphasizes that the use of brain imaging in this context is in a discovery phase, but has the potential to increase our understanding of the neural underpinnings of chronic pain, inform the development of therapeutic agents, and predict treatment outcomes for use in personalized pain management. The task force proposes standards of evidence that must be satisfied before any brain imaging measure can be considered suitable for clinical or legal purposes. The admissibility of such evidence in legal cases also strongly depends on laws that vary between jurisdictions. For these reasons, the task force concludes that the use of brain imaging findings to support or dispute a claim of chronic pain - effectively as a pain lie detector - is not warranted, but that imaging should be used to further our understanding of the mechanisms underlying pain.

Multivariate Brain Prediction of Heart Rate and Skin Conductance Responses to Social Threat

Psychosocial stressors induce autonomic nervous system (ANS) responses in multiple body systems that are linked to health risks. Much work has focused on the common effects of stress, but ANS responses in different body systems are dissociable and may result from distinct patterns of cortical-subcortical interactions. Here, we used machine learning to develop multivariate patterns of fMRI activity predictive of heart rate (HR) and skin conductance level (SCL) responses during social threat in humans (N = 18). Overall, brain patterns predicted both HR and SCL in cross-validated analyses successfully (r_HR = 0.54, r_SCL = 0.58, both p < 0.0001). These patterns partly reflected central stress mechanisms common to both responses because each pattern predicted the other signal to some degree (r_HR→SCL = 0.21 and r_SCL→HR = 0.22, both p < 0.01), but they were largely physiological response specific. Both patterns included positive predictive weights in dorsal anterior cingulate and cerebellum and negative weights in ventromedial PFC and local pattern similarity analyses within these regions suggested that they encode common central stress mechanisms. However, the predictive maps and searchlight analysis suggested that the patterns predictive of HR and SCL were substantially different across most of the brain, including significant differences in ventromedial PFC, insula, lateral PFC, pre-SMA, and dmPFC. Overall, the results indicate that specific patterns of cerebral activity track threat-induced autonomic responses in specific body systems. Physiological measures of threat are not interchangeable, but rather reflect specific interactions among brain systems.

SIGNIFICANCE STATEMENT

We show that threat-induced increases in heart rate and skin conductance share some common representations in the brain, located mainly in the vmPFC, temporal and parahippocampal cortices, thalamus, and brainstem. However, despite these similarities, the brain patterns that predict these two autonomic responses are largely distinct. This evidence for largely output-measure-specific regulation of autonomic responses argues against a common system hypothesis and provides evidence that different autonomic measures reflect distinct, measurable patterns of cortical-subcortical interactions.

From the Brain to the Field: The Applications of Social Neuroscience to Economics, Health and Law

Social neuroscience aims to understand the biological systems that underlie people’s thoughts, feelings and actions in light of the social context in which they operate. Over the past few decades, social neuroscience has captured the interest of scholars, practitioners, and experts in other disciplines, as well as the general public who more and more draw upon the insights and methods of social neuroscience to explain, predict and change behavior. With the popularity of the field growing, it has become increasingly important to consider the validity of social neuroscience findings as well as what questions it can and cannot address. In the present review article, we examine the contribution of social neuroscience to economics, health, and law, three domains with clear societal relevance. We address the concerns that the extrapolation of neuroscientific results to applied social issues raises within each of these domains, and we suggest guidelines and good practices to circumvent these concerns.

Imaging empathy and prosocial emotions

Empathy is a multi-faceted construct with important implications for social behavior. Based on a selective review of the neuroscientific evidence collected in humans, the present paper discusses the neural representations underlying affect sharing, its relation to mentalizing, the importance of self-other distinction, the distinction between empathy, sympathy and compassion, and how these phenomena are linked to prosocial behavior. Apart from reviewing the literature, we also highlight open questions and how they might be addressed by a research approach that tries to integrate across these diverse constructs.

Modeling Pain Using fMRI: From Regions to Biomarkers

Pain is a subjective and complex phenomenon. Its complexity is related to its heterogeneity: multiple component processes, including sensation, affect, and cognition, contribute to pain experience and reporting. These components are likely to be encoded in distributed brain networks that interact to create pain experience and pain-related decision-making. Therefore, to understand pain, we must identify these networks and build models of these interactions that yield testable predictions about pain-related outcomes. We have developed several such models or 'signatures' of pain, by (1) integrating activity across multiple systems, and (2) using pattern-recognition to identify processes related to pain experience. One model, the Neurologic Pain Signature, is sensitive and specific to pain in individuals, involves brain regions that receive nociceptive afferents, and shows little effect of expectation or self-regulation in tests to date. Another, the 'Stimulus Intensity-Independent Pain Signature', explains substantial additional variation in trial-to-trial pain reports. It involves many brain regions that do not show increased activity in proportion to noxious stimulus intensity, including medial and lateral prefrontal cortex, nucleus accumbens, and hippocampus. Responses in this system mediate expectancy and perceived control effects in several studies. Overall, this approach provides a pathway to understanding pain by identifying multiple systems that track different aspects of pain. Such componential models can be combined in unique ways on a subject-by-subject basis to explain an individual's pain experience.

Multivariate pattern analysis utilizing structural or functional MRI-In individuals with musculoskeletal pain and healthy controls: A systematic review

OBJECTIVE

The purpose of this systematic review is to systematically review the evidence relating to findings generated by multivariate pattern analysis (MVPA) following structural or functional magnetic resonance imaging (fMRI) to determine if this analysis is able to: a) Discriminate between individuals with musculoskeletal pain and healthy controls, b) Predict pain perception in healthy individuals stimulated with a noxious stimulus compared to those stimulated with a non-noxious stimulus.

METHODS

MEDLINE, CINAHL, Embase, PEDro, Google Scholar, Cochrane library and Web of Science were systematically screened for relevant literature using different combinations of keywords regarding structural and functional MRI analysed with MVPA, both in individuals with musculoskeletal pain and healthy controls. Reference lists of included articles were hand-searched for additional literature. Eligible articles were assessed on risk of bias and reviewed by two independent researchers.

RESULTS

The search query returned 18 articles meeting the inclusion criteria. Methodological quality varied from poor to good. Seven studies investigated the ability of machine-learning algorithms to differentiate patient groups from healthy control participants. Overall, the review demonstrated that MVPA can discriminate between individuals with MSK pain and healthy controls with an overall accuracy ranging from 53% to 94%. Twelve studies utilized healthy control participants (using them as their own controls), during experimental pain paradigms aimed to investigate the ability of machine-learning to differentiate individuals stimulated with noxious stimuli from those stimulated with non-noxious stimuli, with 'pain' detection rates ranging from 60% to 94%. However, significant heterogeneity in patient conditions, study methodology and brain imaging techniques resulted in various findings that make study comparisons and formal conclusions challenging.

CONCLUSION

There is preliminary and emerging evidence that MVPA analyses of structural or functional MRI are able to discriminate between patients and healthy controls, and also discriminate between noxious and non-noxious stimulation. No prospective studies were found in this review to allow determination of the prognostic or diagnostic capabilities or treatment responsiveness of these analyses. Future studies would also benefit from combining various behavioural, genotype and phenotype data into analyses to assist with development of sensitive and specific signatures that could guide future individualized patient treatment options and evaluate how treatments exert their effects.

Perceiving rejection by others: Relationship between rejection sensitivity and the spontaneous neuronal activity of the brain

Rejection sensitivity (RS) can be defined as the disposition of a person to anxiously expect, readily perceive, and intensely react to rejection. Individuals with high RS are likely to suffer from mental disorders. The association between individual differences in RS and spontaneous neuronal activity at resting state has not yet been investigated. In this study, resting state data were used to investigate the relationship between RS and spontaneous neuronal activity in a large sample of healthy men (137) and women (172). The participants completed the rejection sensitivity questionnaire and underwent resting-state magnetic resonance imaging scan. Multiple regression analysis was conducted to examine the correlation between the regional amplitude of low-frequency fluctuations (ALFF) and rejection sensitivity scores adjusted for age and sex. Results showed that the ALFF value in the subgenual anterior cingulate cortex (sgACC) was positively associated with RS. Furthermore, functional connectivity with the middle frontal gyrus was negatively correlated with RS when sgACC was used as the seed region. These findings suggest that the spontaneous neuronal activity of sgACC and its functional connectivity with the lateral prefrontal cortex which are involved in experiencing social exclusion and regulating negative emotions are associated with individual differences in RS.

Empathic Care and Distress: Predictive Brain Markers and Dissociable Brain Systems

Encountering another's suffering can elicit both empathic distress and empathic care-the warm desire to affiliate. It remains unclear whether these two feelings can be accurately and differentially predicted from neural activity and to what extent their neural substrates can be distinguished. We developed fMRI markers predicting moment-by-moment intensity levels of care and distress intensity while participants (n = 66) listened to true biographies describing human suffering. Both markers' predictions correlated strongly with self-report in out-of-sample participants (r = 0.59 and r = 0.63, p < 0.00001), and both markers predicted later trial-by-trial charitable donation amounts (p < 0.05). Empathic care was preferentially associated with nucleus accumbens and medial orbitofrontal cortex activity, whereas distress was preferentially associated with premotor and somatosensory cortical activity. In tests of marker specificity with an independent behavioral sample (n = 200), the empathic care marker was associated with a mixed-valence feeling state, whereas the empathic distress marker was specific to negative emotion.

Acetaminophen study yields new insights into neurobiological underpinnings of empathy

Empathy is a cornerstone of social behavior, impairments of which are characteristic of neuropsychiatric disorders such as autism and psychopathy. According to the “shared representations” theory, empathy relies on neural processes similar to those underpinning the first-hand experience of a given emotion. A recent study by Mischkowski, Crocker, and Way (Soc Cogn Affect Neurosci 11: 1345–1353, 2016) provides novel insights into neurobiological underpinnings of empathy by demonstrating that acetaminophen, a widely used painkiller, reduces empathy for other's physical and social pain.

The push of social pain: Does rejection's sting motivate subsequent social reconnection?

Physical pain motivates the healing of somatic injuries, yet it remains unknown whether social pain serves a similarly reparative function toward social injuries. Given the substantial overlap between physical and social pain, we predicted that social pain would mediate the effect of rejection on greater motivation for social reconnection and affiliative behavior toward rejecters. In Study 1, the effect of rejection on an increased need to belong was mediated by reports of more intense social pain. In Study 2, three neural signatures of social pain (i.e., activity in the dorsal anterior cingulate cortex, left and right anterior insula during social rejection), each predicted greater behavioral proximity to rejecters. Our findings reify the overlap between social and physical pain. Furthermore, these results are some of the first to demonstrate the reparative nature of social pain and lend insight into how this process may be harnessed to promote postrejection reconnection.

Contextual modulation of pain sensitivity utilising virtual environments

BACKGROUND

Investigating psychological mechanisms that modulate pain, such as those that might be accessed by manipulation of context, is of great interest to researchers seeking to better understand and treat pain. The aim of this study was to better understand the interaction between pain sensitivity, and contexts with inherent emotional and social salience - by exploiting modern immersive virtual reality (VR) technology.

METHODS

A within-subjects, randomised, double-blinded, repeated measures (RM) design was used. In total, 25 healthy participants were exposed to neutral, pleasant, threatening, socially positive and socially negative contexts, using an Oculus Rift DK2. Pressure pain thresholds (PPTs) were recorded in each context, as well as prior to and following the procedure. We also investigated whether trait anxiety and pain catastrophisation interacted with the relationship between the different contexts and pain.

RESULTS

Pressure pain sensitivity was not modulated by context (p = 0.48). Anxiety and pain catastrophisation were not significantly associated with PPTs, nor did they interact with the relationship between context and PPTs.

CONCLUSION

Contrary to our hypothesis, socially and emotionally salient contexts did not influence pain thresholds. In light of other research, we suggest that pain outcomes might only be tenable to manipulation by contextual cues if they specifically manipulate the meaning of the pain-eliciting stimulus, rather than manipulate psychological state generally - as per the current study. Future research might exploit immersive VR technology to better explore the link between noxious stimuli and contexts that directly alter its threat value.