Social and non-social feedback stimuli lead to comparable levels of reward learning and reward responsiveness in an online probabilistic reward task.

Social stimuli seem to be processed more easily and efficiently than non-social stimuli. The current study tested whether social feedback stimuli improve reward learning in a probabilistic reward task (PRT), in which one response option is usually rewarded more often than the other via presentation of non-social reward stimuli. In a pre-registered online study with 305 participants, 75 participants were presented with a non-social feedback stimulus (a star) and information about gains, which is typically used in published PRT studies. Three other groups (with 73-82 participants each) were presented with one of three social feedback stimuli: verbal praise, an attractive happy face, or a "thumbs up"-picture. The data were analysed based on classical signal detection theory, drift diffusion modelling, and Bayesian analyses of null effects. All PRT variants yielded the expected behavioural preference for the more frequently rewarded response. There was no processing advantage of social over non-social feedback stimuli. Bayesian analyses further supported the observation that social feedback stimuli neither increased nor decreased behavioural preferences in the PRT. The current findings suggest that the PRT is a robust experimental paradigm independent of the applied feedback stimuli. They also suggest that the occurrence of a processing advantage for social feedback stimuli is dependent on the experimental task and design.

Hungry for compliments? Ghrelin is not associated with neural responses to social rewards or their pleasantness.

The stomach-derived hormone ghrelin motivates food search and stimulates food consumption, with highest plasma concentrations before a meal and lowest shortly after. However, ghrelin also appears to affect the value of non-food rewards such as interaction with rat conspecifics, and monetary rewards in humans. The present pre-registered study investigated how nutritional state and ghrelin concentrations are related to the subjective and neural responses to social and non-social rewards. In a cross-over feed-and-fast design, 67 healthy volunteers (20 women) underwent functional magnetic resonance imaging (fMRI) in a hungry state and after a meal with repeated plasma ghrelin measurements. In task 1, participants received social rewards in the form of approving expert feedback, or non-social computer reward. In task 2, participants rated the pleasantness of compliments and neutral statements. Nutritional state and ghrelin concentrations did not affect the response to social reward in task 1. In contrast, ventromedial prefrontal cortical activation to non-social rewards was reduced when the meal strongly suppressed ghrelin. In task 2, fasting increased activation in the right ventral striatum during all statements, but ghrelin concentrations were neither associated with brain activation nor with experienced pleasantness. Complementary Bayesian analyses provided moderate evidence for a lack of correlation between ghrelin concentrations and behavioral and neural responses to social rewards, but moderate evidence for an association between ghrelin and non-social rewards. This suggests that ghrelin's influence may be restricted to non-social rewards. Social rewards implemented via social recognition and affirmation may be too abstract and complex to be susceptible to ghrelin's influence. In contrast, the non-social reward was associated with the expectation of a material object that was handed out after the experiment. This may indicate that ghrelin might be involved in anticipatory rather than consummatory phases of reward.

Social exclusion evokes different psychophysiological responses in individuals high on the psychopathy facets fearless dominance and self-centered impulsivity.

Individuals with psychopathic personality traits are generally thought to have difficulties in processing and experiencing emotions. These difficulties could also translate to emotionally charged social situations such as social exclusion. Being socially excluded is often experienced as stressful and unpleasant, potentially even leading to selfish or aggressive behavior-both of which are linked to certain aspects of psychopathy. The current study investigated self-report and physiological responses to social exclusion in the cyberball paradigm in a carefully selected community sample of individuals either scoring high on primary (N = 24) or secondary psychopathy traits (N = 17). Across the sample, the cyberball paradigm decreased experiences of joy and approach motivation, increased subjective anger reports, and induced changes in heart rate. In contrast, individuals scoring high on secondary psychopathy traits (Self-Centered Impulsivity group) displayed stronger physiological reactivity during a habituation phase of prolonged social exclusion than individuals scoring high on primary psychopathy traits (Fearless Dominance group), indexed by changes in skin conductance level. Moreover, a potential mismatch between self-reported and physiological arousal seemed to be only observable in individuals with high secondary psychopathy traits. Overall, the current results suggest diverging patterns of emotional processing and regulation in a social exclusion situation when comparing well-functioning individuals with varying psychopathy traits. It seemed as if individuals high on primary psychopathy traits were insensitive to contextual social cues, while individuals high on secondary psychopathy traits were more affected by the potentially threatening social situation. Cautiously transferring the current findings to forensic samples, they support the idea of moving from a behavioral understanding of the psychopathy construct to a more clinical picture with distinct cognitive and emotional processing patterns in individuals high on either primary or secondary psychopathy traits.

Sex difference in human olfactory sensitivity is associated with plasma adiponectin.

Energy deprivation as well as hormones that regulate appetite and eating can influence olfactory function. This study investigated olfactory sensitivity for a food-related and a non-food odour prior to and after a meal, and its relationship to the energy-regulating hormones ghrelin and adiponectin. The olfactory sensitivity for orange and rose (PEA) odour in healthy, normal-weight volunteers (19 women, 45 men, 1 undisclosed individual) was not affected by the consumption of a meal. Olfactory sensitivity was not associated with concentrations of circulating ghrelin. However, olfactory sensitivity was higher for women than for men, indicating better olfactory performance. This difference between women and men was related to concentrations of plasma adiponectin, an adipose-specific hormone. Adiponectin may thus explain why sex differences in olfactory sensitivity emerge, and may also account for some of the inconsistencies in previous findings on sex differences. Our findings add to the limited literature on the impact of stomach and adipose tissue-derived hormones on olfactory sensitivity. Further studies are needed to establish a causal link between circulating adiponectin and a sex difference in olfactory sensitivity.

Dynamic Causal Modeling of the Prefrontal/Amygdala Network During Processing of Emotional Faces.

Introduction: The importance of the amygdala/medial orbitofrontal cortex (OFC) network during processing of emotional stimuli, emotional faces in particular, is well established. This premise is supported by converging evidence from animal models, human neuroanatomical results, and neuroimaging studies. However, there is missing evidence from human brain connectivity studies that the OFC and no other prefrontal brain areas such as the dorsolateral prefrontal cortex (DLPFC) or ventrolateral prefrontal cortex (VLPFC) are responsible for amygdala regulation in the functional context of emotional face stimuli. Methods: Dynamic causal modeling of ultrahigh-field functional magnetic resonance imaging data acquired at 7 Tesla in 38 healthy subjects and a well-established paradigm for emotional face processing were used to assess the central role of the OFC to provide empirical validation for the assumed network architecture. Results: Using Bayesian model selection, it is demonstrated that indeed the OFC, and not the VLPFC and the DLPFC, downregulates amygdala activation during the emotion discrimination task. In addition, Bayesian model averaging group results were rigorously tested using bootstrapping, further corroborating these findings and providing an estimator for robustness and optimal sample sizes. Discussion: While it is true that VLPFC and DLPFC are relevant for the processing of emotional faces and are connected to the OFC, the OFC appears to be a central hub for the prefrontal/amygdala interaction. Impact statement Using dynamic causal modeling (DCM), abnormal effective connectivity in the orbitofrontal cortex (OFC)/amygdala network has been repeatedly observed in the pathophysiology of psychiatric disorders. However, it has to be considered that these findings are all based on the a priori assumption of the OFC being the central area for prefrontal control regulating amygdala activation. This is particularly important, as DCM results conditionally depend on the underlying model space used for model selection. Using Bayesian model comparison methods, it is shown that the OFC (and not the dorsolateral prefrontal cortex or ventrolateral prefrontal cortex) engages in amygdala downregulation in the context emotional face processing.

Give me a pain that I am used to: distinct habituation patterns to painful and non-painful stimulation.

Pain habituation is associated with a decrease of activation in brain areas related to pain perception. However, little is known about the specificity of these decreases to pain, as habituation has also been described for other responses like spinal reflexes and other sensory responses. Thus, it might be hypothesized that previously reported reductions in activation are not specifically related to pain habituation. For this reason, we performed a 3 T fMRI study using either painful or non-painful electrical stimulation via an electrode attached to the back of the left hand. Contrasting painful vs. non-painful stimulation revealed significant activation clusters in regions well-known to be related to pain processing, such as bilateral anterior and posterior insula, primary/secondary sensory cortices (S1/S2) and anterior midcingulate cortex (aMCC). Importantly, our results show distinct habituation patterns for painful (in aMCC) and non-painful (contralateral claustrum) stimulation, while similar habituation for both types of stimulation was identified in bilateral inferior frontal gyrus (IFG) and contralateral S2. Our findings thus distinguish a general habituation in somatosensory processing (S2) and reduced attention (IFG) from specific pain and non-pain related habituation effects where pain-specific habituation effects within the aMCC highlight a change in affective pain perception.

Chronic non-medical prescription opioid use and empathy for pain: Does pain make the difference?

Non-medical prescription opioid use (NMPOU) is at the heart of the opioid epidemic in the United States. Although chronic opioid use is commonly accompanied by deficits in social functioning, little is known about the impact of chronic NMPOU on social cognitive functions. Social neuroscience models suggest that empathy activates similar or even equivalent neural structures as those underpinning the first-hand experience in that emotional state (e.g., pain). Therefore, we measured subjective and psychophysiological responses during an empathy-for-pain task in 23 individuals with NMPOU, objectively confirmed by hair and urine testing, and compared them with 29 opioid-naïve healthy controls. NMPOU individuals showed lower other-related and self-related unpleasantness ratings when seeing others in pain than controls. No differences between the control and NMPOU group were found in skin conductance responses and heart rate variability (HRV) assessed by root mean square of successive differences (RMSSD) in response to the task. However, RMSSD-HRV was strongly negatively correlated with self-related unpleasantness and craving in the NMPOU group. A subsequent mediation analysis showed a total effect of RMSSD-HRV on self-related unpleasantness with no mediation of craving. This indicates that stronger emotion regulation indexed by high RMSSD-HRV might have downregulating effects on sharing others' pain in NMPOU individuals but not in healthy controls, which was further accompanied by decreased ratings of personal distress and empathetic concern. These results contribute to a better understanding of social functioning in chronic opioid users, suggesting adequate emotion regulation and empathy trainings as therapeutic targets for future interventions of opioid use disorders and long-term pain treatment with opioids.

ERP evidence suggests that confrontation with deterministic statements aligns subsequent other- and self-relevant error processing.

This study used event-related potential (ERP) measurements to investigate whether error processing in a social context is modulated by top-down influence of deterministic thinking, i.e., subjective beliefs that events are pre-determined by previously existing causes. To this end, half of our participants were confronted with statements denying the existence of free will, aimed to induce more deterministic thinking, whereas the other half was assigned to a control group that read neutral statements. Thereafter, all participants performed a choice-reaction task for their own and for the benefit of a second participant. Error rates were comparable in both groups and benefit settings, while only control participants showed enhanced post-error slowing (PES) in other- compared to self-relevant trials. On the neural level, other-relevant errors elicited diminished early error signals (reduced ΔERN amplitudes) in deterministic-intervention participants compared to controls. In subsequent processing, ERPs of deterministic-intervention participants did not differentiate between the benefit settings, while controls showed reduced ΔPe amplitudes for others compared to self-relevant errors. Taken together, our findings suggest that being confronted with deterministic compared to control statements reduced subsequent processing differences between other- and self-relevant error processing. This might be beneficial in social evaluation or intergroup situations because it could decrease self-cenetred processing biases often observed in these situations.

Ghrelin Induces Place Preference for Social Interaction in the Larger Peer of a Male Rat Pair.

Social interaction is important for survival in most social species including humans. To ensure social activities, individuals experience reward from social interaction, generating a powerfully reinforcing process. Here we hypothesized that reward from social interaction in a juvenile male rat pair may be enhanced by ghrelin, a circulating hormone that has been shown to enhance reward from other natural (e.g. food, sex) as well as artificial reinforcers (e.g. alcohol and other drugs of abuse). To this end, we assessed the impact of ghrelin and a ghrelin antagonist on preference for a chamber previously paired to the presence of a social partner in a conditioned place preference paradigm. We found that ghrelin increased and a ghrelin antagonist decreased preference for social interaction, but only in the heavier partner in a social pair. In addition, we found that administered ghrelin induced a positive association between preference for social interaction and body weight difference within socially interacting pairs, where larger ghrelin treated rats preferred social interaction, whereas smaller ghrelin treated rats avoided it, which raises the question if ghrelin could have a role in implementing social hierarchies in rats. In summary, we conclude that ghrelin signaling increases the reward from social interaction in a manner that reflects the degree of divergence in body weight between the social pair.

Increasing self-other bodily overlap increases sensorimotor resonance to others' pain.

Empathy for another person's pain and feeling pain oneself seem to be accompanied by similar or shared neural responses. Such shared responses could be achieved by mapping the bodily states of others onto our own bodily representations. We investigated whether sensorimotor neural responses to the pain of others are increased when experimentally reducing perceived bodily distinction between the self and the other. Healthy adult participants watched video clips of the hands of ethnic ingroup or outgroup members being painfully penetrated by a needle syringe or touched by a cotton swab. Manipulating the video presentation to create a visuospatial overlap between the observer's and the target's hand increased the perceived bodily self-attribution of the target's hand. For both ingroup and outgroup targets, this resulted in increased neural responses to the painful injections (compared with nonpainful contacts), as indexed by desynchronizations of central mu and beta scalp rhythms recorded using electroencephalography. Furthermore, these empathy-related neural activations were stronger in participants who reported stronger bodily self-attribution of the other person's hand. Our findings provide further evidence that empathy for pain engages sensorimotor resonance mechanisms. They also indicate that reducing bodily self-other distinction may increase such resonance for ingroup as well as outgroup targets.

Neural mechanisms of reinforcement learning under mortality threat.

Reinforcement learning - to adjust behaviors in response to feedback regarding reward and punishment - is pivotal to our survival. The present work investigated whether and how reinforcement learning is affected by thoughts of mortality that endanger one's survival. We recorded electroencephalographic while adults performed a probabilistic learning task that required a forced-choice between two visual patterns for monetary reward for different beneficiaries (i.e., self, stranger, or no one) followed by reward or no-reward feedback. We found that verbal reminders of mortality (vs. negative emotion) enlarged an early positive component (P1) at the occipital electrodes but decreased a late positive potential (LPP) at the frontocentral electrodes in response to learning stimuli. While no-reward feedback relative to reward feedback stimuli elicited a feedback-related negativity (FRN) and increased non-phase locked theta band (4-8 Hz) activity at the frontocentral electrodes during reward learning for all beneficiaries, verbal reminders of mortality (vs. negative emotion) significantly reduced the FRN amplitude but failed to modulate the theta band activity. These results suggest that mortality salience enhances early attentional processing but dampens late cognitive evaluation of the learning stimuli during reinforcement learning. Moreover, mortality salience decreases the neural sensitivity to feedback signaling the absence of monetary reward.

Stress management in obesity during a thermal spa residential programme (ObesiStress): protocol for a randomised controlled trial study.

INTRODUCTION: Stress and obesity are two public health issues. The relationship between obesity and stress is biological through the actions of stress on the major hormones that regulate appetite (leptin and ghrelin). Many spa resorts in France specialise in the treatment of obesity, but no thermal spa currently proposes a specific programme to manage stress in obesity. The ObesiStress protocol has been designed to offer a new residential stress management programme. This thermal spa treatment of obesity implements stress management strategies as suggested by international recommendations. METHODS AND ANALYSIS: 140 overweight or obese participants with a Body Mass Index of >25 kg/m2 and aged over 18 years will be recruited. Participants will be randomised into two groups: a control group of usual practice (restrictive diet, physical activity and thermal spa treatment) and an intervention group with stress management in addition to the usual practice. In the present protocol, parameters will be measured on five occasions (at inclusion, at the beginning of the spa (day 0), at the end of the spa (day 21), and at 6 and 12 months). The study will assess the participants' heart rate variability, cardiac remodelling and function, electrodermal activity, blood markers, anthropometric profile, body composition, psychology and quality of life via the use of questionnaires and bone parameters. ETHICS AND DISSEMINATION: The ObesiStress protocol complies with the ethics guidelines for Clinical Research and has been approved by the ethics committee (CPP Sud-Est VI, Clermont-Ferrand - ANSM: 2016-A01774-47). This study aimed to highlight the efficacy of a 21-day thermal spa residential programme of stress management in obesity through objective measurements of well-being and cardiovascular morbidity. Results will be disseminated during several research conferences and articles published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT03578757.

Fairness norm violations in anti-social psychopathic offenders in a repeated trust game.

Psychopathic offenders have a high propensity to violate social norms, as indicated for instance by their widespread lying and cheating behaviour. The reasons for their norm violations are not well understood, though, as they are able to recognise norms in a given situation and also punish norm violators. In this study, we investigated whether psychopathic offenders would violate fairness norms during a repeated trust game because of increased profit-maximising concerns. We measured back-transfer decisions in the repeated trust game, and affective arousal by means of skin conductance responses (SCR) in violent offenders with varying degrees of psychopathy, and non-offenders with low-trait psychopathy. Psychopathy in offenders was measured with the Psychopathy Checklist-Revised (PCL-R). In the task, a participant and an interaction partner entrusted each other money for multiple rounds with the goal to earn as much money as possible. Fairness norm violations were positively associated with Factor 2 scores (the lifestyle/anti-social psychopathy subscale) of the PCL-R, but this was not accompanied by clear profit-maximising behaviour. In addition, anticipatory arousal to self-advantageous decisions was higher in all offenders, independent of their degree of psychopathy, compared with non-offenders. The results of our study widen our understanding of social decision-making in psychopathy. They also suggest treatment possibilities in offenders scoring high on Factor 2, targeting empathic concern and related prosocial intentions to overcome norm-violating behaviour.

Converging electrophysiological evidence for a processing advantage of social over nonsocial feedback.

We recently demonstrated a processing advantage of social versus nonsocial feedback stimuli in a western sample by assessing phase-locked neural responses. The current study extended our previous findings to another cultural sample (Chinese) to further test whether non-phase-locked neural oscillations also exhibit the social feedback processing advantage. Fifty-three Chinese volunteers performed a time estimation task with social and nonsocial feedback stimuli (matched for complexity) while electroencephalogram was recorded. Almost entirely replicating our previous results, feedback ERPs showed a processing advantage for social compared with nonsocial stimuli. Importantly, non-phase-locked oscillations also revealed this pattern. Frontal midline theta (FMΘ) oscillations differentiated between negative and positive feedback to a larger extent in response to social compared with nonsocial feedback. The current findings imply a rather universal effect of social stimulus characteristics during feedback processing and further corroborate the notion of social content as a distinct stimulus category.

Hippocampal Subfields in Acute and Remitted Depression-an Ultra-High Field Magnetic Resonance Imaging Study.

BACKGROUND: Studies investigating hippocampal volume changes after treatment with serotonergic antidepressants in patients with major depressive disorder yielded inconsistent results, and effects on hippocampal subfields are unclear. METHODS: To detail treatment effects on total hippocampal and subfield volumes, we conducted an open-label study with escitalopram followed by venlafaxine upon nonresponse in 20 unmedicated patients with major depressive disorder. Before and after 12 weeks treatment, we measured total hippocampal formation volumes and subfield volumes with ultra-high field (7 Tesla), T1-weighted, structural magnetic resonance imaging, and FreeSurfer. Twenty-eight remitted patients and 22 healthy subjects were included as controls. We hypothesized to detect increased volumes after treatment in major depressive disorder. RESULTS: We did not detect treatment-related changes of total hippocampal or subfield volumes in patients with major depressive disorder. Secondary results indicated that the control group of untreated, stable remitted patients, compared with healthy controls, had larger volumes of the right hippocampal-amygdaloid transition area and right fissure at both measurement time points. Depressed patients exhibited larger volumes of the right subiculum compared with healthy controls at MRI-2. Exploratory data analyses indicated lower baseline volumes in the subgroup of remitting (n = 10) vs nonremitting (n = 10) acute patients. CONCLUSIONS: The results demonstrate that monoaminergic antidepressant treatment in major depressive disorder patients was not associated with volume changes in hippocampal subfields. Studies with larger sample sizes to detect smaller effects as well as other imaging modalities are needed to further assess the impact of antidepressant treatment on hippocampal subfields.

Correction to: The pulvinar nucleus and antidepressant treatment: dynamic modeling of antidepressant response and remission with ultra-high field functional MRI.

The author list was presented as last name, first name. The names should have been listed as:Christoph Kraus, Manfred Klöbl, Martin Tik, Bastian Auer, Thomas Vanicek, Nicole Geissberger, Daniela M. Pfabigan, Andreas Hahn, Michael Woletz, Katharina Paul, Arkadiusz Komorowski, Siegfried Kasper, Christian Windischberger, Claus Lamm, Rupert Lanzenberger.

Social dimension and complexity differentially influence brain responses during feedback processing.

Recent research emphasizes the importance of social factors during performance monitoring. Thus, the current study investigated the impact of social stimuli -such as communicative gestures- on feedback processing. Moreover, it addressed a shortcoming of previous studies, which failed to consider stimulus complexity as potential confounding factor. Twenty-four volunteers performed a time estimation task while their electroencephalogram was recorded. Either social complex, social non-complex, non-social complex, or non-social non-complex stimuli were used to provide performance feedback. No effects of social dimension or complexity were found for task performance. In contrast, Feedback-Related Negativity (FRN) and P300 amplitudes were sensitive to both factors, with larger FRN and P300 amplitudes after social compared to non-social stimuli, and larger FRN amplitudes after complex positive than non-complex positive stimuli. P2 amplitudes were solely sensitive to feedback valence and social dimension. Subjectively, social complex stimuli were rated as more motivating than non-social complex ones. Independently of each other, social dimension and visual complexity influenced amplitude variation during performance monitoring. Social stimuli seem to be perceived as more salient, which is corroborated by P2, FRN and P300 results, as well as by subjective ratings. This could be explained due to their given relevance during every day social interactions.

The pulvinar nucleus and antidepressant treatment: dynamic modeling of antidepressant response and remission with ultra-high field functional MRI.

Functional magnetic resonance imaging (fMRI) successfully disentangled neuronal pathophysiology of major depression (MD), but only a few fMRI studies have investigated correlates and predictors of remission. Moreover, most studies have used clinical outcome parameters from two time points, which do not optimally depict differential response times. Therefore, we aimed to detect neuronal correlates of response and remission in an antidepressant treatment study with 7 T fMRI, potentially harnessing advances in detection power and spatial specificity. Moreover, we modeled outcome parameters from multiple study visits during a 12-week antidepressant fMRI study in 26 acute (aMD) patients compared to 36 stable remitted (rMD) patients and 33 healthy control subjects (HC). During an electrical painful stimulation task, significantly higher baseline activity in aMD compared to HC and rMD in the medial thalamic nuclei of the pulvinar was detected (p = 0.004, FWE-corrected), which was reduced by treatment. Moreover, clinical response followed a sigmoid function with a plateau phase in the beginning, a rapid decline and a further plateau at treatment end. By modeling the dynamic speed of response with fMRI-data, perigenual anterior cingulate activity after treatment was significantly associated with antidepressant response (p < 0.001, FWE-corrected). Temporoparietal junction (TPJ) baseline activity significantly predicted non-remission after 2 antidepressant trials (p = 0.005, FWE-corrected). The results underline the importance of the medial thalamus, attention networks in MD and antidepressant treatment. Moreover, by using a sigmoid model, this study provides a novel method to analyze the dynamic nature of response and remission for future trials.