The impact of social exclusion and loneliness: neural mechanisms and interventions
Freitag, 04.06.2021:
14:45 - 16:15

Chair der Sitzung: Dirk Scheele, Universität Oldenburg
Chair der Sitzung: Alexander Lischke, Medical School Hamburg
Ort: Clinical challenges and the ageing brain

Zusammenfassung der Sitzung

Humans have evolved as an essentially social species. Positive social relationships promote physical and mental well-being, whereas loneliness and social isolation increase the risk of premature mortality comparable to established risk factors such as obesity, physical inactivity, and substance abuse. Surprisingly, however, the impact of social exclusion and loneliness on the structure and function of the brain is still not well understood. In the current symposium, we present recent studies examining the functional and structural brain correlates of social exclusion and loneliness and how they might be modulated by behavioral interventions. Shuyan Liu explores the association between modern urbanicity, social exclusion, and mental health. Jana Lieberz reveals the neural link between loneliness and biased trustworthiness decisions in a pre-stratified sample of healthy lonely and non-lonely individuals. Federica Riva presents the relationship between loneliness and interoception at both behavioral and brain level. Alexander Lischke shows that social network size affects the structural integrity of the amygdala. Zoé Bürger investigates the effects of social exclusion and cognitive stress on the neural functional connectivity in women and men.


Social exclusion, poverty and mental health

Shuyan Liu, Andreas Heinz

Charité – Universitätsmedizin Berlin, Germany

Urbanization can increase the prevalence of mental disorder due to a variety of factors including higher levels of poverty. Social participation promotes resilience against mental health problems, while social stress (such as exclusion) facilitates mental disorders. There is increasing evidence that vulnerable populations (e.g. those that are socio-economically disadvantaged, ethnic minorities and low-income) are more susceptible to a range of mental disorders. Such vulnerability is predicated on the stresses and risks to which individuals and groups are subjected, including lack of social support as indicated by the so-called ethic density effect; here it was repeatedly shown that minority patients show higher rates of schizophrenia when living relatively isolated in their neighbourhoods. Our research group showed that an increasing mental health burden was associated with increasing neighbourhood poverty, independent of individual-level differences in socio-economic status. This effect was more pronounced in inhabitants with migration backgrounds. Regarding potential mechanisms mediating the effects of urbanicity and social stress on individual mental health, both currently living in a city and experiencing an urban upbringing can affect neural processing of stress exposure. Stress effects on dopaminergic and serotonergic neurotransmission modulate neural processing of affective stimuli and thus may explain interactions between urbanicity, stress exposure, and limbic brain activation. These findings suggest that income inequality and minority status may interact with further urban risk factors and increase the mental health burden. Thus, there is a need to integrate social sciences, neurosciences, and public policy to respond to the major health challenges of urbanization.

The neural underpinnings of altered interpersonal trust in loneliness

Jana Lieberz1, Simone G. Shamay-Tsoory2, Nira Saporta2, Timo Esser1, Ekaterina Kuskova1, Birgit Stoffel-Wagner3, René Hurlemann4,5, Dirk Scheele1,4

1Division of Medical Psychology, Department of Psychiatry and Psychotherapy, University Hospital Bonn, 53105 Bonn, Germany; 2Department of Psychology, University of Haifa, Haifa 3498838, Israel; 3Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn, 53105 Bonn, Germany; 4Department of Psychiatry, School of Medicine & Health Sciences, University of Oldenburg, 26129 Oldenburg, Germany; 5Research Center Neurosensory Science, University of Oldenburg, 26129 Oldenburg, Germany

Loneliness is a painful condition associated with increased risk for premature mortality. The formation of new, positive social relationships can alleviate feelings of loneliness, but requires rapid trustworthiness decisions during initial encounters and it is still unclear how loneliness hinders interpersonal trust. Here, we use a multimodal approach including behavioral, psychophysiological, hormonal, and neuroimaging measurements to probe a trust-based mechanism underlying impaired social interactions in loneliness. Pre-stratified healthy individuals with high loneliness scores (n = 42 out of a screened sample of 3678 adults) show reduced oxytocinergic and affective responsiveness to a positive conversation, report less interpersonal trust, and prefer larger social distances compared to controls (n = 40). Moreover, lonely individuals are rated as less trustworthy compared to controls and identified by the blinded confederate better than chance. During initial trust decisions, lonely individuals exhibit attenuated limbic and striatal activation and blunted functional connectivity between the anterior insula and occipitoparietal regions, which correlates with the diminished affective responsiveness to the positive social interaction. This neural response pattern is not mediated by loneliness-associated psychological symptoms. Thus, our results indicate compromised integration of trust-related information as a shared neurobiological component in loneliness, yielding a reciprocally reinforced trust bias in social dyads. The analysis plan of this study was preregistered and the data that support the findings of this study are openly available.

Lonely hearts: an fMRI study on interoception in loneliness

Federica Riva

Department of Cognition, Emotion, and Methods in Psychology; University of Vienna, Austria

Interoception refers to the sensing of internal bodily states. According to a widely accepted model, interoception encompasses three dimensions: interoceptive accuracy (IAcc), the ability to track your own physiological states; interoceptive sensibility (IS), the perception of one’s own ability to appraise interoceptive signals; interoceptive awareness (IAwa), the relationship between (objective) accuracy and (subjective) sensibility. Recent studies have shown the relevance of interoception for social connectedness. Higher IAcc was found to be associated with better emotion regulation following negative social situations, while temporary social exclusion resulted in an acute decrease in IAcc. However, no studies have so far investigated the relation of interoception with loneliness, an extreme case of poor social connectedness. Loneliness is defined as the negative subjective feeling that one’s needs of social companionship are not being met. Thus, the aim of the present study was to investigate how interoception and its neural correlates are related to loneliness. To this purpose, 63 participants performed a heartbeat counting task while in the MR scanner. Heartbeats were measured with a pulsemeter. Two control conditions were included: exteroceptive (counting tones) and time estimation (counting seconds). For each condition, accuracies were computed. IS was measured with confidence ratings during the task and with the Multidimensional Assessment of Interoceptive Awareness. Loneliness was measured with the UCLA loneliness scale. Results will be discussed in light of the relationship of loneliness with the three dimensions of interoception, controlled for the other conditions. This study will shed more light on the relevance of interoception in social connectedness.

Sex- and subregion-specific associations between amygdala structure and social network indices – a community based imaging study with more than 900 individuals

Alexander Lischke1,2, Martin Domin3, Hans Grabe4, Katharina Wittfeld4, Carsten Schmidt5, Norbert Hosten3, Martin Lotze3

1Department of Psychology, Medical School Hamburg, Germany; 2Department of Psychology, University of Greifswald, Germany; 3Department of Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Germany; 4Department of Psychiatry and Psychotherapy, University Medicine Greifswald, Germany; 5Institute for Community Medicine, University Medicine, Greifswald, Germany

Since the dawn of humankind, human individuals have been living in groups. Group living was highly adaptive because it increased the chances for survival. However, survival chances only increased for individuals who were able to navigate these groups. Navigation of groups depends on social skills, implying that evolution facilitated the development of neural circuits that are necessary for the expression of these skills. Most of these circuits are centered on the amygdala, an evolutionarily conserved structure that is associated with a plethora of social skills. Previous studies revealed associations between amygdala structure and social skills that are relevant for social contacts and social networks. These associations emerged in simple analyses that were based on small and unrepresentative samples, leaving open whether these findings can be replicated and extended in analyses that are more sophisticated. To address this issue, we performed a structural imaging study in a representative sample of over 900 individuals. After asking for the number of social contacts and social networks, we analyzed the structural integrity of the amygdala. In contrast to previous studies, we considered different amygdala subregions in our analyses. These analyses revealed sex- and subregion-specific associations of amygdala structure with the number of social networks but not with the number of social contacts. Given that more skills are needed to navigate social networks than social contacts, may explain why amygdala structure was exclusively associated with the number of social networks.

The impact of social exclusion and cognitive stress on resting-state functional connectivity of amygdala–frontal cortex networks in healthy women and men

Zoé Bürger1, Veronika I. Müller2,3, Simon Eickhoff2,3, Ute Habel4,5, Birgit Derntl1,6, Lydia Kogler1

1Department of Psychiatry and Psychotherapy, Medical Faculty, University of Tübingen, Germany; 2Institute of Neuroscience und Medicine, INM-7, Research Centre Jülich, Jülich, Germany; 3Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University, Düsseldorf, German; 4Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany; 5JARA BRAIN Institute I, Translational Brain Medicine, Jülich/Aachen, Germany; 6LEAD Graduate School and Research Network, University of Tübingen, Germany

Social exclusion (EXC) and cognitive stress (STRESS) are two different stressors occurring in everyday life. They affect behaviour, physiology and neural functional connectivity. Based on a recently postulated neural model on stress regulation, we investigated the effect of EXC and STRESS on resting-state functional connectivity (rsFC) of the amygdalae with medial and lateral frontal regions in healthy women (n=40) and men (n=37). Resting-state, subjective, and hormonal data were assessed before and following social exclusion and cognitive stress in all participants. Subjective data indicates increased anger after both paradigms, with higher levels after STRESS compared to EXC. Further, positive affect decreased while negative affect increased after STRESS, apparent in both, women and men, with no such effect for social exclusion. Cortisol levels showed an increase after EXC in women, while STRESS did not yield cortisol changes in both sexes. Results on rsFC indicate stressor-dependent sex differences: Before EXC, men had higher rsFC between left amygdala and left dorsal anterior cingulate cortex (dACC), whereas after EXC, they showed higher rsFC between left amygdala and right ventro-medial prefrontal cortex (vmPFC) than women. For STRESS, women had higher rsFC between left amygdala and right medial prefrontal cortex (mPFC) before than afterwards compared to men.

Higher rsFC between left amygdala and right mPFC indicates an increased stress reactivity, whereas rsFC between left amygdala and left dACC was associated with better stress recovery. These results show stressor-dependent sex differences in rsFC of the amygdalae with the frontal cortex, supporting the assumption of the stress regulation model.