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Emotional coordination constitutes one of the crucial building blocks for social adaptation. Humans, like other primate species, are able to rapidly and accurately respond to others' non-verbal emotional signals by preparing and executing adaptive motor responses. In this chapter, we present a general overview of how emotional expressions emitted by others promote, in the observer’s brain, fast processing and elaboration of multiple possibilities for action of different levels of complexity, from stimulus-driven reactions to goal-directed actions, via different communicating subcortical and cortical pathways, that compete to flexibly orchestrate our social behavior.

Merely perceiving objects usually grasped with a power or a precision grip (e.g., an apple vs. a cherry) potentiate power-grip and precision-grip responses, respectively. According to the size-coding account, this potentiation effect is due to the compatibility between size codes associated with both stimuli and responses, rather than to the simulation of motor information stored at a conceptual level (i.e., the embodied account). At the stimulus level, size-coding would occur, because objects associated with a power grip are usually presented in a larger visual size than objects associated with a precision grip. However, this explanation is challenged by results, showing that reading nouns of objects associated with power or precision grip also leads to potentiation effects, even though the visual size of the displayed object is no longer perceived. Therefore, we designed three experiments to better understand this word-based potentiation effect and to investigate whether it relies on size codes. Our results showed a word-based potentiation effect only when the object nouns were interleaved with pictures depicting the objects in their typical visual size. We discuss the contributions of these results for both the size-coding account and the embodied account of the potentiation effect of grasping behaviors.

The capability model of alpha asymmetries posits that state emotional manipulations are a more powerful detector of depression-related motivational deficits than alpha activity at rest. The present study used a time-frequency approach to investigate the temporal dynamics of event-related changes in alpha power during passive viewing of emotional pictures in individuals with dysphoria (n = 23) and in individuals without dysphoria (n = 24). In the whole group, the processing of pleasant and unpleasant compared to neutral pictures was associated with a decrease in event-related alpha power (i.e., alpha desynchronization) at centro-parietal and parietal scalp sites in the 538–1400 ms post-stimulus. The group with dysphoria revealed a smaller alpha desynchronization than the group without dysphoria in response to pleasant, but not neutral and unpleasant, stimuli at frontal, fronto-central and centro-parietal sites. Interestingly, at central and centro-parietal scalp sites, the difference between groups in response to pleasant stimuli was lateralized to the right hemisphere, whereas no clear lateralization was observed at frontal and fronto-central scalp sites. These findings suggest that decreased cortical activity (i.e., reduced alpha desynchronization) in a network involving bilateral frontal and right-lateralized parietal regions may provide a specific measure of deficits in approach-related motivation in depression.

Study Objectives Total sleep deprivation is known to have significant detrimental effects on cognitive and socio-emotional functioning. Nonetheless, the mechanisms by which total sleep loss disturbs decision-making in social contexts are poorly understood. Here, we investigated the impact of total sleep deprivation on approach/avoidance decisions when faced with threatening individuals, as well as the potential moderating role of sleep-related mood changes. Methods Participants (n = 34) made spontaneous approach/avoidance decisions in the presence of task-irrelevant angry or fearful individuals, while rested or totally sleep deprived (27 h of continuous wakefulness). Sleep-related changes in mood and sustained attention were assessed using the Positive and Negative Affective Scale and the psychomotor vigilance task, respectively. Results Rested participants avoided both fearful and angry individuals, with stronger avoidance for angry individuals, in line with previous results. On the contrary, totally sleep deprived participants favored neither approach nor avoidance of fearful individuals, while they still comparably avoided angry individuals. Drift-diffusion models showed that this effect was accounted for by the fact that total sleep deprivation reduced value-based evidence accumulation toward avoidance during decision making. Finally, the reduction of positive mood after total sleep deprivation positively correlated with the reduction of fearful display avoidance. Importantly, this correlation was not mediated by a sleep-related reduction in sustained attention. Conclusions All together, these findings support the underestimated role of positive mood-state alterations caused by total sleep loss on approach/avoidance decisions when facing ambiguous socio-emotional displays, such as fear.

International audience; The ability to swiftly and accurately respond to others' non-verbal signals, such as their emotional expressions, constitutes one of the building blocks for social adaptation. It is debated whether rapid action tendencies to socio-emotional signals solely depend upon stimulus-evoked pre-decisional motor bias or can also engage goal-directed (decisional) processes that involve the arbitration between action alternatives. Here, we used drift diffusion models (DDMs) of choice and electroencephalography (EEG) to investigate the impact of threat-signaling individuals (angry or fearful) on spontaneous approach-avoidance decisions. Participants choose to avoid angry individuals more often than fearful ones and this effect was stronger for intense expressions. Diffusion models showed that this pattern of choice was accounted for by a process of value-based evidence accumulation, suggesting an active competition between action options. At the brain level, we found that EEG activity preceding movement initiation (200 ms) in a mid-frontal cluster of electrodes - sourced in the orbital and ventromedial frontal cortices - encoded value difference between chosen and unchosen options, thus predicting participant's choices on a trial-by-trial basis. Furthermore, value difference also modulated EEG signal during feedback about the decision. Altogether, the present findings convincingly support the underestimated influence of implicit goal-directed mechanisms in approach-avoidance responses to socio-emotional signals.

The search for neural correlates of emotional consciousness has gained momentum in the last decades. Nonetheless, disagreements concerning the mechanisms that determine the experiential qualities of emotional consciousness—the “what is it like” to feel an emotion—as well as on their neural correlates have far-reaching consequences on how researchers study and measure emotion, sometimes leading to seemingly irresolvable impasses. The current paper lays out in a balanced way the viewpoint of both cognitive and precognitive approaches to emotional consciousness on the basis of commonalities and differences between the claims of some relevant theories of emotions. We examine the sufficiency of the existing evidence in support of the proposed theories of emotional consciousness by going through the methodological specificity of the study of emotional consciousness and its unique challenges and highlighting what can and cannot be imported by advances in research on perceptual consciousness. We propose that there are three key experimental contrasts that are each equally necessary in the search for the neural correlates of emotional consciousness and each contrast alone coming with its own limitations. We conclude by acknowledging some of the most promising avenues in the field, which may help go beyond the current limitations and collaboratively piece together the puzzle of emotional consciousness.

Research on Autism Spectrum Disorder (ASD) has focused on processing of socially-relevant stimuli, such as faces. Nonetheless, before being 'social', faces are visual stimuli. The present magnetoencephalography study investigated the time course of brain activity during an implicit emotional task in visual emotion-related regions in 19 adults with ASD (mean age 26.3 ± 4.4) and 19 typically developed controls (26.4 ± 4). The results confirmed previously-reported differences between groups in brain responses to emotion and a hypo-activation in the ASD group in the right fusiform gyrus around 150 ms. However, the ASD group also presented early enhanced activity in the occipital region. These results support that impaired face processing in ASD might be sustained by atypical responses in primary visual areas.

Socially-relevant signals benefit from prioritized processing, from initial orientation to behavioral choice elaboration. Yet it remains unclear whether such prioritized processing engages specific or similar neural computations as the processing of non-social cues during decision-making. To address this question, we developed a novel behavioral paradigm in which participants performed two different detection tasks on the same, two-dimensional visual stimuli. We presented morphed facial displays of emotion (from neutral to angry) on top of a morphed colored background (from grey to violet). Participants were asked to report the presence or absence of either emotion (anger) or color (violet) in the stimulus, while ignoring the other task-irrelevant dimension. Importantly, we equalized detection sensitivity across dimensions using an adaptive titration procedure. Computational modeling of electroencephalographic (EEG) activity revealed that emotion cues benefit from a prioritized neural coding in action-selective brain regions. First, premotor EEG activity scales with the amount of perceptual evidence earlier, around 150ms, when the decision concerns emotion rather than color. Second, participant choice was decoded earlier during emotion (260ms) than color decisions in band-limited EEG power in the same premotor regions. Third, these two effects varied across participants as a function of their social anxiety. Together, these findings indicate a selective, prioritized neural representation of socially-relevant signals in motor preparation regions during perceptual decision-making.

Several studies have examined the neural correlates of mood-related emotional processing in depression, showing a greater reduction of activity in the rostral anterior cingulate cortex (rACC) in response to pleasant relative to unpleasant stimuli in depressed individuals, and the opposite pattern in healthy controls. The present study aimed at examining whether frontal theta activity—an electrophysiological measure of rACC activity—could be a reliable EEG correlate of mood-related emotional processing in individuals with dysphoria. To this end, the EEG was recorded in 27 individuals with dysphoria and 29 individuals without dysphoria during an emotional imagery task, including pleasant, neutral and unpleasant scripts. Self-reported valence, arousal and vividness, and changes in frontal theta activity were measured during the task. Frontal theta activity was more reduced from baseline to the imagery of pleasant relative to unpleasant scripts in the group with dysphoria, whereas the opposite pattern of reduction was noted in the group without dysphoria. In addition, more severe depressive symptoms were correlated with greater reduction in frontal theta activity in response to pleasant, but not neutral and unpleasant, scripts. No differences between groups in subjective ratings were noted. Consistent with the key role of rACC activity in depression-related emotional dysregulation, these findings suggest that frontal theta activity may be an EEG correlate of mood-related emotional processing in dysphoria. The current study also suggests that dysphoria is more likely to be associated with abnormal processing of pleasant rather than unpleasant stimuli.

Prefrontal brain regions have been proposed to modulate vagally mediated heart rate variability (HRV) through their action on subcortical structures. This study aimed at investigating the beat-to-beat influence of the brain cortex over the heart through a high temporal resolution estimation of brain-heart coupling. Electrocardiogram (ECG) and electroencephalogram (EEG) from 32 scalp positions were recorded at rest for 5 min in 38 participants. To assess beat-to-beat cortical control on vagal activity, the longest and shortest inter-beat intervals (IBIs) were identified for each participant. Then, the EEG activity was time-locked to R waves in the ECG signal and analyzed using a time-frequency approach. Logistic regression models were applied to predict the trial-by-trial occurrence of long and short IBIs from cardiac-related EEG activity. Delta power reduction over prefrontal and frontocentral areas preceding the R-wave increased the probability for a long IBI to occur, as compared to a short one. Moreover, reduced prefrontal delta power preceding the R wave was correlated to higher cardiac vagal control, as reflected by the High Frequency (HF) power of HRV calculated on the whole recording time. The present results support the hypothesis that phasic activation/deactivation of prefrontal areas modulates vagal control of heart rate at rest.

Frontal alpha asymmetry has been proposed to underlie the balance between approach and withdrawal motivation associated to each individual's affective style. Neurofeedback of EEG frontal alpha asymmetry represents a promising tool to reduce negative affect, although its specific effects on left/right frontal activity and approach/withdrawal motivation are still unclear. The present study employed a neurofeedback training to increase frontal alpha asymmetry (right - left), in order to evaluate discrete changes in alpha power at left and right sites, as well as in positive and negative affect, anxiety and depression. Thirty-two right-handed females were randomly assigned to receive either the neurofeedback on frontal alpha asymmetry, or an active control training (N = 16 in each group). The asymmetry group showed an increase in alpha asymmetry driven by higher alpha at the right site (p < 0.001), as well as a coherent reduction in both negative affect and anxiety symptoms (ps < 0.05), from pre-to post-training. No training-specific modulation emerged for positive affect and depressive symptoms. These findings provide a strong rationale for the use of frontal alpha asymmetry neurofeedback for the reduction of negative affect and anxiety in clinical settings.

Background Socio-emotional difficulties in autism spectrum disorder (ASD) are thought to reflect impaired functional connectivity within the “social brain”. Nonetheless, a whole-brain characterization of the fast responses in functional connectivity during implicit processing of emotional faces in adults with ASD is lacking. Methods The present study used magnetoencephalography to investigate early responses in functional connectivity, as measured by interregional phase synchronization, during implicit processing of angry, neutral and happy faces. The sample (n = 44) consisted of 22 young adults with ASD and 22 age- and sex-matched typically developed (TD) controls. Results Reduced phase-synchrony in the beta band around 300 ms emerged during processing of angry faces in the ASD compared to TD group, involving key areas of the social brain. In the same time window, de-synchronization in the beta band in the amygdala was reduced in the ASD group across conditions. Conclusions This is the first demonstration of atypical global and local synchrony patterns in the social brain in adults with ASD during implicit processing of emotional faces. The present results replicate and substantially extend previous findings on adolescents, highlighting that atypical brain synchrony during processing of socio-emotional stimuli is a hallmark of clinical sequelae in autism. Electronic supplementary material The online version of this article (doi:10.1186/s13229-017-0123-2) contains supplementary material, which is available to authorized users.

Background: Somatic, but not cognitive-affective, symptoms of depression have been associated with reduced heart rate variability (HRV), and with poor prognosis in cardiovascular patients. However, factors concomitant with cardiovascular diseases may confound the relationship between somatic symptoms of depression and reduced HRV. Therefore, this study examined whether reduced HRV was differentially associated with cognitive-affective and somatic symptoms of depression in medically healthy individuals with and without dysphoria.Methods: Self-reported cognitive-affective and somatic symptoms as measured with the Beck Depression Inventory-II (BDI-II) questionnaire and time and frequency domain parameters of HRV were collected in 62 medically healthy individuals, of whom 25 with and 37 without dysphoria.Results: Somatic, but not cognitive-affective, symptoms of depression were inversely associated with standard deviation of NN intervals (SDNN) (beta = -0.476, p < .05), number of interval differences of successive NN intervals greater than 50 ms (NN50) (beta = -0.498, p < .03), and HRV total power (beta = -0.494, p < .04) in the group with dysphoria, after controlling for sex, anxiety and lifestyle factors. Cognitive-affective and somatic symptoms were not related to any of the HRV parameters in the group without dysphoria (all ps > .24).Conclusions: By showing that the relationship between somatic depressive symptoms and reduced HRV extends to medically healthy individuals with dysphoria, the present findings suggest that this association is independent of factors concomitant with cardiovascular diseases. The present study also suggests that individuals with somatic rather than cognitive-affective subsets of depressive symptoms may be at greater risk for developing cardiovascular diseases.

Studies on electroencephalographic (EEG) alpha band asymmetry at rest have reported that, compared to healthy controls, dysphoric and clinically depressed individuals often display relatively less left- than right-sided cortical activity at anterior scalp sites, and the opposite pattern at posterior scalp sites. It has also been shown that depression-related differences in alpha lateralization at anterior and posterior sites are more likely to emerge during emotional tasks and during visuospatial tasks, respectively, rather than during resting conditions. However, although it is the well-established that posterior cortical activity plays a key role also in emotional processing in healthy individuals, the influence of dysphoria on posterior alpha asymmetry sites during an emotional task has yet to be examined. To this end, dysphoric ( n = 23) and nondysphoric ( n = 24) individuals performed an emotional imagery task including pleasant, neutral, and unpleasant narratives. The group with, but not without, dysphoria showed reduced left relative to right cortical activity at anterior sites, irrespective of emotional condition. By contrast, at posterior sites, individuals with dysphoria showed reduced right relative to left parietal activity during unpleasant, but not pleasant and neutral, imagery condition compared to nondysphoric individuals. Results at anterior scalp sites provide further evidence for the presence of a stable pattern of reduced approach motivation in dysphoric individuals. The association between dysphoria and right relative to left parietal hypoactivation in response to unpleasant imagery suggests that dysphoric individuals are more likely to use state-dependent dysfunctional strategies to regulate negative emotions compared to nondysphoric individuals.

The present study investigated emotional responding in dysphoric individuals. Dysphoric ( N = 25) and nondysphoric ( N = 29) individuals completed an emotional imagery task, including pleasant, neutral and unpleasant emotional-eliciting scripts. Self-reported valence and arousal, and measures of cardiac autonomic activity were collected during the task. Compared to nondysphoric controls, dysphoric individuals showed a reduced heart rate increase to pleasant scripts. Less vagal withdrawal in response to pleasant scripts was also found in dysphoric, but not in nondysphoric, individuals. Conversely, no differences between groups in autonomic responding to unpleasant scripts and in subjective measures were noted. Overall, our data showed that dysphoria is characterized by blunted cardiac autonomic reactivity in response to positive rather than negative emotional stimuli. The present findings also suggest that the lack of vagal suppression may reflect a reduced sensitivity to positive environmental stimuli, which, in turn, has been implicated in the development of major depression in dysphoric individuals.