Mixed emotions to social situations: An fMRI investigation.

BACKGROUND: Neuroscience research has generally studied emotions each taken in isolation. However, mixed emotional states (e.g., the co-occurrence of amusement and disgust, or sadness and pleasure) are common in everyday life. Psychophysiological and behavioral evidence suggests that mixed emotions may have response profiles that are distinguishable from their constituent emotions. Yet, the brain bases of mixed emotions remain unresolved. METHODS: We recruited 38 healthy adults who viewed short, validated film clips, eliciting either positive (amusing), negative (disgusting), neutral, or mixed (a mix of amusement and disgust) emotional states, while brain activity was assessed by functional magnetic resonance imaging (fMRI). We assessed mixed emotions in two ways: first by comparing neural reactivity to ambiguous (mixed) with that to unambiguous (positive and negative) film clips and second by conducting parametric analyses to measure neural reactivity with respect to individual emotional states. We thus obtained self-reports of amusement and disgust after each clip and computed a minimum feeling score (shared minimum of amusement and disgust) to quantify mixed emotional feelings. RESULTS: Both analyses revealed a network of the posterior cingulate (PCC), medial superior parietal lobe (SPL)/precuneus, and parieto-occipital sulcus to be involved in ambiguous contexts eliciting mixed emotions. CONCLUSION: Our results are the first to shed light on the dedicated neural processes involved in dynamic social ambiguity processing. They suggest both higher-order (SPL) and lower-order (PCC) processes may be needed to process emotionally complex social scenes.

Trait Empathy Shapes Neural Responses Toward Sad Music.

Individuals with a predisposition to empathize engage with sad music in a compelling way, experiencing overall more pleasurable emotions. However, the neural mechanisms underlying these music-related experiences in empathic individuals are unknown. The present study tested whether dispositional empathy modulates neural responses to sad compared with happy music. Twenty-four participants underwent fMRI while listening to 4-min blocks of music evoking sadness or happiness. Using voxel-wise regression, we found a positive correlation between trait empathy (with scores assessed by the Interpersonal Reactivity Index) and eigenvector centrality values in the ventromedial prefrontal cortex (vmPFC), including the medial orbitofrontal cortex (mOFC). We then performed a functional connectivity (FC) analysis to detect network nodes showing stronger FC with the vmPFC/mOFC during the presentation of sad versus happy music. By doing so, we identified a "music-empathy" network (vmPFC/mOFC, dorsomedial prefrontal cortex, primary visual cortex, bilateral claustrum and putamen, and cerebellum) that is spontaneously recruited while listening to sad music and includes brain regions that support the coding of compassion, mentalizing, and visual mental imagery. Importantly, our findings extend the current understanding of empathic behaviors to the musical domain and pinpoint sad music as an effective stimulus to be employed in social neuroscience research.

The Temporal Pole Top-Down Modulates the Ventral Visual Stream During Social Cognition.

The temporal pole (TP) has been associated with diverse functions of social cognition and emotion processing. Although the underlying mechanism remains elusive, one possibility is that TP acts as domain-general hub integrating socioemotional information. To test this, 26 participants were presented with 60 empathy-evoking film clips during fMRI scanning. The film clips were preceded by a linguistic sad or neutral context and half of the clips were accompanied by sad music. In line with its hypothesized role, TP was involved in the processing of sad context and furthermore tracked participants' empathic concern. To examine the neuromodulatory impact of TP, we applied nonlinear dynamic causal modeling to a multisensory integration network from previous work consisting of superior temporal gyrus (STG), fusiform gyrus (FG), and amygdala, which was extended by an additional node in the TP. Bayesian model comparison revealed a gating of STG and TP on fusiform-amygdalar coupling and an increase of TP to FG connectivity during the integration of contextual information. Moreover, these backward projections were strengthened by emotional music. The findings indicate that during social cognition, TP integrates information from different modalities and top-down modulates lower-level perceptual areas in the ventral visual stream as a function of integration demands.

Comparison of Four fMRI Paradigms Probing Emotion Processing.

Previous fMRI research has applied a variety of tasks to examine brain activity underlying emotion processing. While task characteristics are known to have a substantial influence on the elicited activations, direct comparisons of tasks that could guide study planning are scarce. We aimed to provide a comparison of four common emotion processing tasks based on the same analysis pipeline to suggest tasks best suited for the study of certain target brain regions. We studied an n-back task using emotional words (EMOBACK) as well as passive viewing tasks of emotional faces (FACES) and emotional scenes (OASIS and IAPS). We compared the activation patterns elicited by these tasks in four regions of interest (the amygdala, anterior insula, dorsolateral prefrontal cortex (dlPFC) and pregenual anterior cingulate cortex (pgACC)) in three samples of healthy adults (N = 45). The EMOBACK task elicited activation in the right dlPFC and bilateral anterior insula and deactivation in the pgACC while the FACES task recruited the bilateral amygdala. The IAPS and OASIS tasks showed similar activation patterns recruiting the bilateral amygdala and anterior insula. We conclude that these tasks can be used to study different regions involved in emotion processing and that the information provided is valuable for future research and the development of fMRI biomarkers.

Hippocampal-Temporopolar Connectivity Contributes to Episodic Simulation During Social Cognition.

People are better able to empathize with others when they are given information concerning the context driving that person's experiences. This suggests that people draw on prior memories when empathizing, but the mechanisms underlying this connection remain largely unexplored. The present study investigates how variations in episodic information shape the emotional response towards a movie character. Episodic information is either absent or provided by a written context preceding empathic film clips. It was shown that sad context information increases empathic concern for a movie character. This was tracked by neural activity in the temporal pole (TP) and anterior hippocampus (aHP). Dynamic causal modeling with Bayesian Model Selection has shown that context changes the effective connectivity from left aHP to the right TP. The same crossed-hemispheric coupling was found during rest, when people are left to their own thoughts. We conclude that (i) that the integration of episodic memory also supports the specific case of integrating context into empathic judgments, (ii) the right TP supports emotion processing by integrating episodic memory into empathic inferences, and (iii) lateral integration is a key process for episodic simulation during rest and during task. We propose that a disruption of the mechanism may underlie empathy deficits in clinical conditions, such as autism spectrum disorder.

Reward and loss anticipation in panic disorder: An fMRI study.

Anticipatory anxiety and harm avoidance are essential features of panic disorder (PD) and may involve deficits in the reward system of the brain, in particular in the ventral striatum. While neuroimaging studies on PD have focused on fearful and negative affective stimulus processing, no investigations have directly addressed deficits in reward and loss anticipation. To determine whether the ventral striatum shows abnormal neural activity in PD patients during anticipation of loss or gain, an event-related functional magnetic resonance imaging experiment using a monetary incentive delay task was employed in 10 patients with PD and 10 healthy controls. A repeated-measures ANOVA to identify effects of group (PD vs. Control) and condition (anticipation of loss vs. gain vs. neutral outcome) revealed that patients with PD showed significantly reduced bilateral ventral striatal activation during reward anticipation but increased activity during loss anticipation. Within the patient group, the degree of activation in the ventral striatum during loss-anticipation was positively correlated with harm avoidance and negatively correlated with novelty seeking. These findings suggest that behavioural impairments in panic disorder may be related to abnormal neural processing of motivational cues.

Effects of Sad and Happy Music on Mind-Wandering and the Default Mode Network.

Music is a ubiquitous phenomenon in human cultures, mostly due to its power to evoke and regulate emotions. However, effects of music evoking different emotional experiences such as sadness and happiness on cognition, and in particular on self-generated thought, are unknown. Here we use probe-caught thought sampling and functional magnetic resonance imaging (fMRI) to investigate the influence of sad and happy music on mind-wandering and its underlying neuronal mechanisms. In three experiments we found that sad music, compared with happy music, is associated with stronger mind-wandering (Experiments 1A and 1B) and greater centrality of the nodes of the Default Mode Network (DMN) (Experiment 2). Thus, our results demonstrate that, when listening to sad vs. happy music, people withdraw their attention inwards and engage in spontaneous, self-referential cognitive processes. Importantly, our results also underscore that DMN activity can be modulated as a function of sad and happy music. These findings call for a systematic investigation of the relation between music and thought, having broad implications for the use of music in education and clinical settings.

Alterations of cerebral glutamate in the euthymic state of patients with bipolar disorder.

The pathophysiology of bipolar disorder (BD) mostly remains unclear. However, some findings argue for a dysfunction in glutamatergic neurotransmission in BD. Proton magnetic resonance spectroscopy at 3T was used to determine glutamate concentrations in the anterior cingulate cortex (ACC) and the hippocampus (HC) of euthymic outpatients with BP-I disorder and age- and sex-matched healthy controls. In patients with BD, glutamate concentrations were significantly increased in the ACC and decreased in the HC compared with concentrations in controls. Significant group differences were also measured for N-acetyl aspartate and choline; no differences were found for other metabolites examined. An inverse correlation was observed for glutamate concentrations in the ACC and number of episodes. The findings of the study add to the concept of abnormalities in glutamatergic regulation in the ACC and HC in patients with BD.

The eyes have it: the role of attention in cognitive reappraisal of social stimuli.

Cognitive reappraisal (CR) is a commonly used emotion-regulation strategy that has been shown to influence affective, cognitive, and social outcomes. Although progress has been made in elucidating the mechanisms underlying CR, the role of attention remains unclear. In the present study, we investigated the role of attention in CR by tracking participants' gazes during the presentation of videos depicting people in negative moods. Participants were asked to attend naturally or to use reappraisal to increase or decrease their emotions while viewing the videos. After each video, they rated their negative emotion experience. Results showed that participants spent more time looking at the emotional regions in the target's face (eyes and mouth) when asked to up-regulate their emotions, compared with when they simply attended to the videos. The reverse pattern was found for down-regulation of emotions. In addition, the effects of cognitive reappraisal on negative emotion experience were mediated by the time spent looking at the emotional regions, with a stronger effect for the down-regulation instruction. Finally, direct effects of regulation instruction on negative emotion were observed even when controlling for time spent viewing emotional regions, which suggests that attention and CR are distinct components that uniquely influence negative emotions. These results complement and extend previous findings on the role of attention in CR, and highlight the importance of taking attentional mechanisms into account when designing CR training.

How music alters a kiss: superior temporal gyrus controls fusiform-amygdalar effective connectivity.

While watching movies, the brain integrates the visual information and the musical soundtrack into a coherent percept. Multisensory integration can lead to emotion elicitation on which soundtrack valences may have a modulatory impact. Here, dynamic kissing scenes from romantic comedies were presented to 22 participants (13 females) during functional magnetic resonance imaging scanning. The kissing scenes were either accompanied by happy music, sad music or no music. Evidence from cross-modal studies motivated a predefined three-region network for multisensory integration of emotion, consisting of fusiform gyrus (FG), amygdala (AMY) and anterior superior temporal gyrus (aSTG). The interactions in this network were investigated using dynamic causal models of effective connectivity. This revealed bilinear modulations by happy and sad music with suppression effects on the connectivity from FG and AMY to aSTG. Non-linear dynamic causal modeling showed a suppressive gating effect of aSTG on fusiform-amygdalar connectivity. In conclusion, fusiform to amygdala coupling strength is modulated via feedback through aSTG as region for multisensory integration of emotional material. This mechanism was emotion-specific and more pronounced for sad music. Therefore, soundtrack valences may modulate emotion elicitation in movies by differentially changing preprocessed visual information to the amygdala.

Emotional picture and word processing: an FMRI study on effects of stimulus complexity.

Neuroscientific investigations regarding aspects of emotional experiences usually focus on one stimulus modality (e.g., pictorial or verbal). Similarities and differences in the processing between the different modalities have rarely been studied directly. The comparison of verbal and pictorial emotional stimuli often reveals a processing advantage of emotional pictures in terms of larger or more pronounced emotion effects evoked by pictorial stimuli. In this study, we examined whether this picture advantage refers to general processing differences or whether it might partly be attributed to differences in visual complexity between pictures and words. We first developed a new stimulus database comprising valence and arousal ratings for more than 200 concrete objects representable in different modalities including different levels of complexity: words, phrases, pictograms, and photographs. Using fMRI we then studied the neural correlates of the processing of these emotional stimuli in a valence judgment task, in which the stimulus material was controlled for differences in emotional arousal. No superiority for the pictorial stimuli was found in terms of emotional information processing with differences between modalities being revealed mainly in perceptual processing regions. While visual complexity might partly account for previously found differences in emotional stimulus processing, the main existing processing differences are probably due to enhanced processing in modality specific perceptual regions. We would suggest that both pictures and words elicit emotional responses with no general superiority for either stimulus modality, while emotional responses to pictures are modulated by perceptual stimulus features, such as picture complexity.