Neural processing of threat cues in social environments

The effect of negative emotion processing on spatial navigation: an experimental study using virtual reality

Finding one's way in unfamiliar environments is an essential ability. When navigating, people are overwhelmed with an enormous amount of information. However, some information might be more relevant than others. Despite the mounting knowledge about the mechanisms underlying orientational skills, and the notable effects of facial emotions on human behavior, little is known about emotions' effects on spatial navigation. Hereby, this study aimed to explore how exposure to others' negative emotional facial expressions affects wayfinding performances. Moreover, gender differences that characterize both processes were considered. Fifty-five participants (31 females) entered twice in three realistic virtual reality environments: the first time, to encode a route to find an object and then to recall the learned path to reach the same object again. In between the two explorations of the virtual environment, participants were asked to undergo a gender categorization task during which they were exposed to sixty faces showing either neutral, fearful, or angry expressions. Results showed a significant interaction between emotions, time, and gender. In particular, the exposition to fearful faces, but not angry and neutral ones, decreased males' wayfinding performances (i.e., travel times and distance travelled), while females' performances were unaffected. Possible explanations for such gender and emotional dissimilarities are discussed.

Association Between Negative Affect and Perceived Mortality Threat During the COVID-19 Pandemic: The Role of Brain Activity and Connectivity

The prevalence of the novel coronavirus (COVID-19) has been considered a major threat to physical and mental health around the world, causing great pressure and mortality threat to most people. The current study aimed to investigate the neurological markers underlying the relationship between perceived mortality threat (PMT) and negative affect (NA). We examined whether the regional amplitude of low-frequency fluctuations (ALFF) and resting-state functional connectivity (RSFC) before the COVID-19 outbreak (October 2019 to December 2019, wave 1) were predictive for NA and PMT during the mid-term of the COVID-19 pandemic (February 22 to 28, 2020, wave 2) among 603 young adults (age range 17-22, 70.8% females). Results indicated that PMT was associated with spontaneous activity in several regions (e.g., inferior temporal gyrus, medial occipital gyrus, medial frontal gyrus, angular gyrus, and cerebellum) and their RSFC with the distributed regions of the default mode network and cognitive control network. Furthermore, longitudinal mediation models showed that ALFF in the cerebellum, medial occipital gyrus, medial frontal gyrus, and angular gyrus (wave 1) predicted PMT (wave 2) through NA (wave 2). These findings revealed functional neural markers of PMT and suggest candidate mechanisms for explaining the complex relationship between NA and mental/neural processing related to PMT in the circumstance of a major crisis.

Sex differences in neural mechanisms of social and non-social threat monitoring

Adolescent males and females differ in their responses to social threat. Yet, threat processing is often probed in non-social contexts using the error-related negativity (ERN; Flanker EEG Task), which does not yield sex-specific outcomes. fMRI studies show inconsistent patterns of sex-specific neural engagement during threat processing. Thus, the relation between threat processing in non-social and social contexts across sexes and the effects perceived level of threat on brain function are unclear. We tested the interactive effect of non-social threat-vigilance (ERN), sex (N = 69; Male=34; 11–14-year-olds), and perceived social threat on brain function while anticipating feedback from ‘unpredictable’, ‘nice’, or ‘mean’ purported peers (fMRI; Virtual School Paradigm). Whole-brain analyses revealed differential engagement of precentral and inferior frontal gyri, putamen, anterior cingulate cortex, and insula. Among males with more threat-vigilant ERNs, greater social threat was associated with increased activation when anticipating unpredictable feedback. Region of interest analyses revealed this same relation in females in the amygdala and anterior hippocampus when anticipating mean feedback. Thus, non-social threat vigilance relates to neural engagement depending on perceived social threat, but peer-based social contexts and brain regions engaged, differ across sexes. This may partially explain divergent psychosocial outcomes in adolescence.

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Responses to social threat differ by sex and likely influence peer victimization.

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Threat processing is often probed in nonsocial contexts and is not sex-specific.

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Responses to type of social threat differed by sex, but relate to response to non-social threat.

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Brain regions engaged during social threat differ by sex.

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Perceived social threat relate to in-vivo peer victimization in both sexes.

First-Person Virtual Embodiment Modulates the Cortical Network that Encodes the Bodily Self and Its Surrounding Space during the Experience of Domestic Violence

Social aggression, such as domestic violence, has been associated with a reduced ability to take on others’ perspectives. In this naturalistic imaging study, we investigated whether training human participants to take on a first-person embodied perspective during the experience of domestic violence enhances the identification with the victim and elicits brain activity associated with the monitoring of the body and surrounding space and the experience of threat. We combined fMRI measurements with preceding virtual reality exposure from either first-person perspective (1PP) or third-person perspective (3PP) to manipulate whether the domestic abuse stimulus was perceived as directed to oneself or another. We found that 1PP exposure increased body ownership and identification with the virtual victim. Furthermore, when the stimulus was perceived as directed toward oneself, the brain network that encodes the bodily self and its surrounding space was more strongly synchronized across participants and connectivity increased from premotor cortex (PM) and intraparietal sulcus towards superior parietal lobe. Additionally, when the stimulus came near the body, brain activity in the amygdala (AMG) strongly synchronized across participants. Exposure to 3PP reduced synchronization of brain activity in the personal space network, increased modulation of visual areas and strengthened functional connectivity between PM, supramarginal gyrus and primary visual cortex. In conclusion, our results suggest that 1PP embodiment training enhances experience from the viewpoint of the virtual victim, which is accompanied by synchronization in the fronto-parietal network to predict actions toward the body and in the AMG to signal the proximity of the stimulus.

An event-related potential comparison of facial expression processing between cartoon and real faces

Faces play important roles in the social lives of humans. Besides real faces, people also encounter numerous cartoon faces in daily life which convey basic emotional states through facial expressions. Using event-related potentials (ERPs), we conducted a facial expression recognition experiment with 17 university students to compare the processing of cartoon faces with that of real faces. This study used face type (real vs. cartoon), emotion valence (happy vs. angry) and participant gender (male vs. female) as independent variables. Reaction time, recognition accuracy, and the amplitudes and latencies of emotion processing-related ERP components such as N170, VPP (vertex positive potential), and LPP (late positive potential) were used as dependent variables. The ERP results revealed that cartoon faces caused larger N170 and VPP amplitudes as well as a briefer N170 latency than did real faces; that real faces induced larger LPP amplitudes than did cartoon faces. In addition, the results showed a significant difference in the brain regions as reflected in a right hemispheric advantage. The behavioral results showed that the reaction times for happy faces were shorter than those for angry faces; that females showed a higher accuracy than did males; and that males showed a higher recognition accuracy for angry faces than happy faces. Due to the sample size, these results may suggestively but not rigorously demonstrate differences in facial expression recognition and neurological processing between cartoon faces and real faces. Cartoon faces showed a higher processing intensity and speed than real faces during the early processing stage. However, more attentional resources were allocated for real faces during the late processing stage.

Exploring the role of testosterone in the cerebellum link to neuroticism: From adolescence to early adulthood

Previous research has found an association between a smaller cerebellar volume and higher levels of neuroticism. The steroid hormone testosterone reduces stress responses and the susceptibility to negative mood. Together with in vitro studies showing a positive effect of testosterone on cerebellar gray matter volumes, we set out to explore the role of testosterone in the relation between cerebellar gray matter and neuroticism. Structural magnetic resonance imaging scans were acquired, and indices of neurotic personality traits were assessed by administering the depression and anxiety scale of the revised NEO personality inventory and Gray's behavioural avoidance in one hundred and forty-nine healthy volunteers between 12 and 27 years of age. Results demonstrated an inverse relation between total brain corrected cerebellar volumes and neurotic personality traits in adolescents and young adults. In males, higher endogenous testosterone levels were associated with lower scores on neurotic personality traits and larger cerebellar gray matter volumes. No such relations were observed in the female participants. Analyses showed that testosterone significantly mediated the relation between male cerebellar gray matter and measures of neuroticism. Our findings on the interrelations between endogenous testosterone, neuroticism and cerebellar morphology provide a cerebellum-oriented framework for the susceptibility to experience negative emotions and mood in adolescence and early adulthood.

Alcohol attenuates amygdala-frontal connectivity during processing social signals in heavy social drinkers: a preliminary pharmaco-fMRI study

RATIONALE

Convergent evidence shows that alcohol exerts its effects on social behavior via modulation of amygdala reactivity to affective stimuli. Given that affective processing involves dynamic interactions between the amygdala and the prefrontal cortex (PFC), alcohol's effects are likely to extend beyond regional changes in brain activity to changes that manifest on a broader functional circuit level.

OBJECTIVE

The current study examines alcohol's effects on functional connectivity (i.e., "coupling") between the amygdala and the PFC during the processing of socio-emotional stimuli using functional magnetic resonance imaging (fMRI).

METHODS

In a randomized, double blind, placebo-controlled, within-subjects cross-over design, 12 heavy, social drinkers performed an fMRI task designed to probe amygdala response to socio-emotional stimuli (angry, fearful, and happy faces) following acute ingestion of alcohol or placebo. Functional connectivity between the amygdala and PFC was examined and compared between alcohol and placebo sessions using a conventional generalized psychophysiological interaction (gPPI) analysis.

RESULTS

Relative to placebo, alcohol reduced functional coupling between the amygdala and the right orbitofrontal cortex (OFC) during processing of both angry and fearful faces. Alcohol also reduced functional coupling between the amygdala and left OFC during processing of happy faces.

CONCLUSIONS

These preliminary findings suggest that alcohol's effects on social behavior may be mediated by alternations in functional connectivity between the amygdala and OFC during processing of emotional faces.

fMRI activities in the emotional cerebellum: a preference for negative stimuli and goal-directed behavior

Several studies indicate that the cerebellum might play a role in experiencing and/or controlling emphatic emotions, but it remains to be determined whether there is a distinction between positive and negative emotions, and, if so, which specific parts of the cerebellum are involved in these types of emotions. Here, we visualized activations of the cerebellum and extracerebellar regions using high-field fMRI, while we asked participants to observe and imitate images with pictures of human faces expressing different emotional states or with moving geometric shapes as control. The state of the emotions could be positive (happiness and surprise), negative (anger and disgust), or neutral. The positive emotional faces only evoked mild activations of crus 2 in the cerebellum, whereas the negative emotional faces evoked prominent activations in lobules VI and VIIa in its hemispheres and lobules VIII and IX in the vermis. The cerebellar activations associated with negative emotions occurred concomitantly with activations of mirror neuron domains such as the insula and amygdala. These data suggest that the potential role of the cerebellum in control of emotions may be particularly relevant for goal-directed behavior that is required for observing and reacting to another person's (negative) expressions.

Alexithymia and the processing of emotional facial expressions (EFEs): systematic review, unanswered questions and further perspectives

Alexithymia is characterized by difficulties in identifying, differentiating and describing feelings. A high prevalence of alexithymia has often been observed in clinical disorders characterized by low social functioning. This review aims to assess the association between alexithymia and the ability to decode emotional facial expressions (EFEs) within clinical and healthy populations. More precisely, this review has four main objectives: (1) to assess if alexithymia is a better predictor of the ability to decode EFEs than the diagnosis of clinical disorder; (2) to assess the influence of comorbid factors (depression and anxiety disorder) on the ability to decode EFE; (3) to investigate if deficits in decoding EFEs are specific to some levels of processing or task types; (4) to investigate if the deficits are specific to particular EFEs. Twenty four studies (behavioural and neuroimaging) were identified through a computerized literature search of Psycinfo, PubMed, and Web of Science databases from 1990 to 2010. Data on methodology, clinical characteristics, and possible confounds were analyzed. The review revealed that: (1) alexithymia is associated with deficits in labelling EFEs among clinical disorders, (2) the level of depression and anxiety partially account for the decoding deficits, (3) alexithymia is associated with reduced perceptual abilities, and is likely to be associated with impaired semantic representations of emotional concepts, and (4) alexithymia is associated with neither specific EFEs nor a specific valence. These studies are discussed with respect to processes involved in the recognition of EFEs. Future directions for research on emotion perception are also discussed.

Transient and sustained neural responses to death-related linguistic cues

Recent research showed that perception of death-related vs death-unrelated linguistic cues produced increased frontoparietal activity but decreased insular activity. This study investigated (i) whether the increased frontoparietal and decreased insular activities are, respectively, associated with transient trial-specific processes of death-related linguistic cues and sustained death-related thought during death-relevance judgments on linguistic cues and (ii) whether the neural activity underlying death-related thought can predict individuals' dispositional death anxiety. Participants were presented with death-related/unrelated words, life-related/unrelated words, and negative-valence/neutral words in separate sessions. Participants were scanned using functional magnetic resonance imaging while performing death-relevance, life-relevance, and valence judgments on the words, respectively. The contrast of death-related vs death-unrelated words during death-relevance judgments revealed transient increased activity in the left inferior parietal lobule, the right frontal eye field, and the right superior parietal lobule. The contrast of death-relevance judgments vs life-relevance/valence judgments showed decreased activity in the bilateral insula. The sustained insular activity was correlated with dispositional death anxiety, but only in those with weak transient frontoparietal responses to death-related words. Our results dissociate the transient and sustained neural responses to death-related linguistic cues and suggest that the combination of the transient and sustained neural activities can predict dispositional death anxiety.

A review on sex differences in processing emotional signals

Interest in sex-related differences in psychological functioning has again come to the foreground with new findings about their possible functional basis in the brain. Sex differences may be one way how evolution has capitalized on the capacity of homologous brain regions to process social information between men and women differently. This paper focuses specifically on the effects of emotional valence, sex of the observed and sex of the observer on regional brain activations. We also discuss the effects of and interactions between environment, hormones, genes and structural differences of the brain in the context of differential brain activity patterns between men and women following exposure to seen expressions of emotion and in this context we outline a number of methodological considerations for future research. Importantly, results show that although women are better at recognizing emotions and express themselves more easily, men show greater responses to threatening cues (dominant, violent or aggressive) and this may reflect different behavioral response tendencies between men and women as well as evolutionary effects. We conclude that sex differences must not be ignored in affective research and more specifically in affective neuroscience.

Extraction of situational meaning by integrating multiple meanings in a complex environment: a functional MRI study

Humans extract behaviorally significant meaning from a situation by integrating meanings from multiple components of a complex daily environment. To determine the neural underpinnings of this ability, the authors performed functional magnetic resonance imaging of healthy subjects while the latter viewed naturalistic scenes of two people and an object, including a threatening situation of a person being attacked by an offender with an object. The authors used a two-factorial design: the object was either aversive or nonaversive, and the offender's action was either directed to the person or elsewhere. This allowed the authors to examine the neural response to object aversiveness and person-directed intention separately. A task unrelated to threat was also used to address incidental (i.e., subconscious or unintentional) detection. Assuming individual differences in incidental threat detection, the authors used a functional connectivity analysis using principal components analysis of intersubject variability. The left lateral orbitofrontal cortex and medial prefrontal cortex (MPFC) were specifically activated in response to a threatening situation. The threat-related component of intersubject variability was extracted from these data and showed a significant correlation with personality scores. There was also a correlation between threat-related intersubject variability and activation for object aversiveness in the left temporal pole and lateral orbitofrontal cortex; person-directed intention in the left superior frontal gyrus; threatening situations in the left MPFC; and independently for both factors in the right MPFC. Results demonstrate independent processing of object aversiveness and person-directed intention in the left temporal-orbitofrontal and superior frontal networks, respectively, and their integration into situational meaning in the MPFC.

The perceived duration of emotional face is influenced by the gaze direction

The present research investigates the effects of gaze direction on the perceived duration of the presentation of angry and happy expressions. When the facial expression was angry, a straight gaze elongated the perceived duration of the expression compared with an averted gaze. However, there was no effect of gaze direction when the facial expression was happy. These findings indicate that the subjective estimation of time is elongated when the observer encounters a socially important survival signal, considering that an angry face with a straight gaze may be perceived as a threat requiring a fight-or-flight response.