Oxytocin differentially modulates the early neural responses to faces and non-social stimuli.

Oxytocin (OT) alters social cognition partly through effects on the processing and appraisal of faces. It is debated whether the hormone also impacts the processing of other, non-social, visual stimuli. To this end, we conducted a randomized, counter-balanced, double-blind, placebo (PL)-controlled within-subjects' electro-encephalography (EEG) study with cismale participants (to control for gender dimorphic hormonal effects; n = 37). Participants received intranasal OT (24IU) and completed a one-back task viewing emotional (fearful/ happy) and neutral faces, and threat (snakes/spiders) and non-threat (mushrooms/flowers) non-social stimuli. OT differentially impacted event-related potentials (ERP)s to faces and non-social stimuli. For faces regardless of emotion, OT evoked greater occipital N1 and anterior P1 amplitudes at ∼155 ms than after PL, and lead to sustained differences over anterior, bilateral parietal and occipital sites from 205 ms onwards. For all non-social stimuli, OT evoked greater right parietal N1 amplitudes, and later only impacted threat stimuli over right parietal and occipital sites. None of these OT-induced modulations was related to individual anxiety levels. This pattern of results indicates that OT differentially modulates the processing of faces and non-social stimuli, and that the hormone's effect on visual processing and cognition does not occur as a function of non-clinical levels of anxiety.

Looming Angry Faces: Preliminary Evidence of Differential Electrophysiological Dynamics for Filtered Stimuli via Low and High Spatial Frequencies.

Looming motion interacts with threatening emotional cues in the initial stages of visual processing. However, the underlying neural networks are unclear. The current study investigated if the interactive effect of threat elicited by angry and looming faces is favoured by rapid, magnocellular neural pathways and if exogenous or endogenous attention influences such processing. Here, EEG/ERP techniques were used to explore the early ERP responses to moving emotional faces filtered for high spatial frequencies (HSF) and low spatial frequencies (LSF). Experiment 1 applied a passive-viewing paradigm, presenting filtered angry and neutral faces in static, approaching, or receding motions on a depth-cued background. In the second experiment, broadband faces (BSF) were included, and endogenous attention was directed to the expression of faces. Our main results showed that regardless of attentional control, P1 was enhanced by BSF angry faces, but neither HSF nor LSF faces drove the effect of facial expressions. Such findings indicate that looming motion and threatening expressions are integrated rapidly at the P1 level but that this processing relies neither on LSF nor on HSF information in isolation. The N170 was enhanced for BSF angry faces regardless of attention but was enhanced for LSF angry faces during passive viewing. These results suggest the involvement of a neural pathway reliant on LSF information at the N170 level. Taken together with previous reports from the literature, this may indicate the involvement of multiple parallel neural pathways during early visual processing of approaching emotional faces.

Faces capture spatial attention only when we want them to: An inattentional blindness EEG study.

Previous research on emotional face processing has shown that emotional faces such as fearful faces may be processed without visual awareness. However, evidence for nonconscious attention capture by fearful faces is limited. In fact, studies using sensory manipulation of awareness (e.g., backward masking paradigms) have shown that fearful faces do not attract attention during subliminal viewings nor when they were task-irrelevant. Here, we used a three-phase inattentional blindness paradigm and electroencephalography to examine whether faces (fearful and neutral) capture attention under different conditions of awareness and task-relevancy. We found that the electrophysiological marker for attention capture, the N2-posterior-contralateral (N2pc), was elicited by face stimuli only when participants were aware of the faces and when they were task-relevant (phase 3). When participants were unaware of the presence of faces (phase 1) or when the faces were irrelevant to the task (phase 2), no N2pc was observed. Together with our previous work, we concluded that fearful faces, or faces in general, do not attract attention unless we want them to.

The effect of social comparison on effort: When similar and slightly better peers increase effort-related cardiovascular responses.

Social comparison theory states that comparison with others should influence an individual's behavior (Festinger, 1954; Munkes & Diehl, 2003). This is primarily due to an upward pressure: the pressure to be better than others, which according to some theories should motivate individuals to increase their level of performance (Munkes & Diehl, 2003; Rijsman, 1974). The effect of upward pressure on individual performance has been tested, but never on effort. To address this gap, we conducted a within-subject design study with N = 40 participants engaged in five-minute video games while presented with scores of a similar, slightly better, or weaker peer, with a control condition omitting the peer's score. Effort-related cardiovascular responses were recorded with initial systolic time interval (ISTI) during the game and baseline conditions. The effect of social comparison on effort was tested with a 4 (social comparison) x 5 (minutes of the tasks) repeated-measures ANOVA on ISTI reactivity. Results showed higher ISTI reactivity, interpreted as increased effort, when participants competed with similar and slightly better peers compared to a weaker peer and the control condition in the last minute of the task, confirming our expectations (Pegna et al., 2019). These results illustrate that social comparison - through its effect on upward pressure - is sufficient to elicit changes in effort-related cardiovascular response.

Fixation-related electrical potentials during a free visual search task reveal the timing of visual awareness.

It has been repeatedly claimed that emotional faces readily capture attention, and that they may be processed without awareness. Yet some observations cast doubt on these assertions. Part of the problem may lie in the experimental paradigms employed. Here, we used a free viewing visual search task during electroencephalographic recordings, where participants searched for either fearful or neutral facial expressions among distractor expressions. Fixation-related potentials were computed for fearful and neutral targets and the response compared for stimuli consciously reported or not. We showed that awareness was associated with an electrophysiological negativity starting at around 110 ms, while emotional expressions were distinguished on the N170 and early posterior negativity only when stimuli were consciously reported. These results suggest that during unconstrained visual search, the earliest electrical correlate of awareness may emerge as early as 110 ms, and fixating at an emotional face without reporting it may not produce any unconscious processing.

Mentalizing and self-other distinction in visual perspective taking: the analysis of temporal neural processing using high-density EEG.

This high density EEG report dissects the neural processing in the visual perspective taking using four experimental comparisons (Arrow, Avatar and Self, Other). Early activation differences occurred between the Avatar and the Arrow condition in primary visual pathways concomitantly with alpha and beta phase locked responses predominant in the Avatar condition. In later time points, brain activation was stronger for the Avatar condition in paracentral lobule of frontal lobe. When taking the other's perspective, there was an increased recruitment of generators in the occipital and temporal lobes and later on in mentalizing and salience networks bilaterally before spreading to right frontal lobe subdivisions. Microstate analysis further supported late recruitment of the medial frontal gyrus and precentral lobule in this condition. Other perspective for the Avatar only showed a strong beta response located first in left occipito-temporal and right parietal areas, and later on in frontal lobes. Our EEG data support distinct brain processes for the Avatar condition with an increased recruitment of brain generators that progresses from primary visual areas to the anterior brain. Taking the other's perspective needs an early recruitment of neural processors in posterior areas involved in theory of mind with later involvement of additional frontal generators.

Decoding neural patterns for the processing of fearful faces under different visual awareness conditions: A multivariate pattern analysis.

Previous studies have provided mixed findings regarding the nonconscious processing of fearful faces. Here, we used multivariate pattern analysis on electroencephalography data from three backward masking experiments to examine the processing of fearful faces under different visual awareness conditions. Three groups of participants were shown pairs of face images presented very briefly (for 16 ms) or for sufficiently long (for 266 ms), and completed tasks where the faces were either relevant to the experimental task (Experiment 1) or not (Experiments 2 and 3). Three main decoding analyses were performed. First, in the visual awareness decoding, the visibility of the faces, and hence participants' awareness of them, was maximally decodable in three time windows: 158-168 ms, 235-260 ms and 400-600 ms where the earlier neural patterns were generalized to the later stage activity. Second, we found that the spatial location of a fearful face in the face pairs was decodable, however only when the faces were consciously seen and task-relevant. Finally, we successfully decoded distinct neural patterns associated with the fearful-face-present conditions, compared to the fearful-face-absent conditions, and these patterns were decodable during both short and long presentations of the faces. Together, our results suggest that, while the processing of the spatial location of fearful faces requires awareness and task-relevancy, the mere presence of fearful faces can be processed even when visual awareness is highly restricted.

Seeing in my way or your way: impact of intelligence, attention, and empathy on brain reactivity.

Previous studies showed that neurotypical adults are able to engage in unconscious analyses of others' mental states in the context of automatic perspective taking and experience systematic difficulties when judging the conflicts between their own (Self) and another's (Other) perspective. Several functional MRI (fMRI) studies reported widespread activation of mentalizing, salience, and executive networks when adopting the Other compared to Self perspective. This study aims to explore whether cognitive and emotional parameters impact on brain reactivity in dot perspective task (dPT). We provide here an fMRI analysis based on individual z-scores in eighty-two healthy adults who underwent the Samson's dPT after detailed assessment of fluid intelligence, attention, levels of alexithymia and social cognition abilities. Univariate regression models were used to explore the association between brain activation patterns and psychological variables. There was a strong positive association between Wechsler Adult Intelligence Scale (WAIS) and fMRI z-scores in Self perspective. When the Other perspective is taken, Continuous Performance Test (CPT)-II parameters were negatively associated with fMRI z-scores. Individuals with higher Toronto Alexithymia scale (TAS) score and lower scores in mini-Social cognition and Emotional Assessment (SEA) displayed significantly higher egocentric interference-related fMRI z-scores. Our data demonstrate that brain activation when focusing on our own perspective depends on the levels of fluid intelligence. Decreased attentional recruitment and decreased inhibitory control affects the brain efforts to adopt the Other perspective. Egocentric interference-associated brain fMRI activation was less marked in cases with better empathy abilities but the opposite was true for persons who experience increased difficulties in the recognition of emotions.

Hierarchical status is rapidly assessed from behaviourally dominant faces.

Recognition of social hierarchy is a key feature that helps us navigate through our complex social environment. Neuroimaging studies have identified brain structures involved in the processing of hierarchical stimuli, but the precise temporal dynamics of brain activity associated with such processing remains largely unknown. In this investigation, we used event-related potentials (ERPs) to examine the effect of social hierarchy on the neural responses elicited by dominant and nondominant faces. Participants played a game where they were led to believe that they were middle-rank players, responding alongside other alleged players, whom they perceived as higher or lower-ranking. ERPs were examined in response to dominant and nondominant faces, and low-resolution electromagnetic tomography (LORETA) was used to identify the implicated brain areas. The results revealed that the amplitude of the N170 component was enhanced for faces of dominant individuals, showing that hierarchy influences the early stages of face processing. A later component, the late positive potential (LPP) appearing between 350-700 ms, also was enhanced for faces of higher-ranking players. Source localisation suggested that the early modulation was due to an enhanced response in limbic regions. These findings provide electrophysiological evidence for enhanced early visual processing of socially dominant faces.

Attentional capture by fearful faces requires consciousness and is modulated by task-relevancy: A dot-probe EEG study.

In the current EEG study, we used a dot-probe task in conjunction with backward masking to examine the neural activity underlying awareness and spatial processing of fearful faces and the neural processes for subsequent cued spatial targets. We presented face images under different viewing conditions (subliminal and supraliminal) and manipulated the relation between a fearful face in the pair and a subsequent target. Our mass univariate analysis showed that fearful faces elicit the N2-posterior-contralateral, indexing spatial attention capture, only when they are presented supraliminally. Consistent with this, the multivariate pattern analysis revealed a successful decoding of the location of the fearful face only in the supraliminal viewing condition. Additionally, the spatial attention capture by fearful faces modulated the processing of subsequent lateralised targets that were spatially congruent with the fearful face, in both al and electrophysiological data. There was no evidence for nonconscious processing of the fearful faces in the current paradigm. We conclude that spatial attentional capture by fearful faces requires visual awareness and it is modulated by top-down task demands.

Patterns of multiple brain network activation in dot perspective task.

In this functional MRI (fMRI) study on 82 healthy adults using the dot perspective task, inconsistency of perspectives was associated with a significant increase of the mean reaction time and number of errors both in Self and Other conditions. Unlike the Arrow (non-mentalizing), the Avatar (mentalizing) paradigm was characterized by the recruitment of parts of the mentalizing and salience networks. These data provide experimental evidence supporting the fMRI distinction between mentalizing and non-mentalizing stimuli. A widespread activation of classical theory of mind (ToM) areas but also of salience network and decision making areas was observed in the Other compared to Self-conditions. Compared to Self-Consistent, Self-Inconsistent trials were related to increased activation in the lateral occipital cortex, right supramarginal and angular gyrus as well as inferior, superior and middle frontal gyri. Compared to the Other-Consistent, Other-Inconsistent trials yielded strong activation in the lateral occipital cortex, precuneus and superior parietal lobule, middle and superior precentral gyri and left frontal pole. These findings reveal that altercentric interference relies on areas involved in self-other distinction, self-updating and central executive functions. In contrast, egocentric interference needs the activation of the mirror neuron system and deductive reasoning, much less related to pure ToM abilities.

Event-Related Potentials Index Prediction Error Signalling During Perceptual Processing of Emotional Facial Expressions.

Humans use socially relevant stimuli to guide perceptual processing of the surrounding environment, with emotional stimuli receiving preferential attention due to their social importance. Predictive coding theory asserts this cognitive process occurs efficiently by combining predictions about what is to be perceived with incoming sensory information, generating prediction errors that are then used to update future predictions. Recent evidence has identified differing neural activity that demonstrates how spatial and feature-based attention may interact with prediction, yet how emotion-guided attention may influence this relationship remains unknown. In the present study, participants viewed a display of two faces in which attention, prediction, and emotion were manipulated, and responded to a face expressing a specific emotion (anger or happiness). The N170 was found to be enhanced by unpredictable as opposed to predictable stimuli, indicating that it indexes general prediction error signalling processes. The N300 amplitudes were also enhanced by unpredictable stimuli, but they were also affected by the attentional status of angry but not happy faces, suggesting that there are differences in prediction error processes indexed by the N170 and N300. Overall, the findings suggest that the N170 and N300 both index violations of expectation for spatial manipulations of stimuli in accordance with prediction error responding processes.

Up close and emotional: Electrophysiological dynamics of approaching angry faces.

Recent evidence suggests that looming emotional faces are processed rapidly by the neural system, and that this apparent approach further interacts with emotion, causing an enhanced neural response for angry expressions. However, previous research has not demonstrated unequivocally if these effects are due to low-level visual features, or if they are indeed due to the emotional content of the stimuli. To address this question, the current study presented upright and inverted angry and neutral faces, which either expanded or contracted in size on a constant depth-cued background, such that they appeared to approach or retreat from the viewer. EEG/ERP measures were used to identify the time course of brain activity for these stimuli. The results showed that when faces were upright, both the P1 and N170 were enhanced for angry expressions, with the P1 being further increased with looming angry faces. The inversion of the faces caused an increase in both the P1 and N170 amplitudes, but no modulation was found for emotions. These findings show an early modulation of brain activity for upright looming angry faces and rule out the influence of low-level visual features as a contributing factor.

Neural processing of lateralised task-irrelevant fearful faces under different awareness conditions.

The neural fate of task-irrelevant emotional faces under different awareness conditions is poorly understood. Here, we examined the electrophysiological activity during an experiment where the location of target information (contrast-induced line) was manipulated orthogonally to the location of task-irrelevant fearful faces, under subliminal or supraliminal viewing conditions. We found that only target lines elicited an N2-posterior-contralateral (N2pc), indexing spatial attention shifting, in the supraliminal condition. No N2pc was found for the targets in the subliminal condition or for task-irrelevant fearful faces in either conditions. However, the mere presence of a fearful face enhanced early neural activity between 200 and 300 ms only in the subliminal condition. Additionally, the presence of a target line, but not a fearful face, enhanced the P3. Our results suggest that the N2pc is dependent on visual awareness and task-relevancy of the information and that laterally-presented task-irrelevant fearful expressions can be processed without awareness during early visual processing.

Violated expectations for spatial and feature attributes of visual trajectories modulate event-related potential amplitudes across the visual processing hierarchy.

During visual perception, the brain must combine its predictions about what is to be perceived with incoming relevant information. The present study investigated how this process interacts with attention by using event-related potentials that index these cognitive mechanisms. Specifically, this study focused on examining how the amplitudes of the N170, N2pc, and N300 would be modulated by violations of expectations for spatial and featural attributes of visual stimuli. Participants viewed a series of shape stimuli in which a salient shape moved across a set of circular locations so that the trajectory of the shape implied the final position and shape of the stimulus. The final salient stimuli occurred in one of four possible outcomes: predictable position and shape, predictable position but unpredictable shape, unpredictable position but predictable shape, and unpredictable position and shape. The N170 was enhanced by unpredictable positions and shapes, whereas the N300 was enlarged only by unpredictable positions. The N2pc was not modulated by violations of expectations for shapes or positions. Additionally, it was observed post-hoc that the P1pc amplitude was increased by unpredictable shapes. These findings revealed that incorrect prediction increases neural activity. Furthermore, they suggest that prediction and attention interact differently in different stages of visual perception, depending on the type of attention being engaged: The N170 indexes initial prediction error signalling irrespective of the type of information (spatial or featural) in which error occurs, followed by the N300 as a marker of prediction updating involving reorientation of spatial attention.

The Effects of Spatial Attention Focus and Visual Awareness on the Processing of Fearful Faces: An ERP Study.

Previous research on the relationship between attention and emotion processing have focused essentially on consciously-viewed, supraliminal stimuli, while the attention-emotion interplay remains unexplored in situations where visual awareness is restricted. Here, we presented participants with face pairs in a backward masking paradigm and examined the electrophysiological activity in response to fearful and neutral expressions under different conditions of attention (spatially attended vs. unattended) and stimulus visibility (subliminal vs. supraliminal). We found an enhanced N2 (visual awareness negativity -VAN-) and an enhanced P3 for supraliminal compared to subliminal faces. The VAN, indexing the early perceptual awareness, was enhanced when the faces were spatially attended compared to when they were unattended, showing that the VAN does not require spatial attention focus but can be enhanced by it. Fearful relative to neutral expressions enhanced the early neural activity (N2) regardless of spatial attention but only in the supraliminal viewing condition. However, fear-related enhancements on later neural activity (P3) were found when stimuli were both attended and presented supraliminally. These findings suggest that visual awareness is needed for emotion processing during both early and late stages. Spatial attention is required for emotion processing at the later stage but not at the early stage.

Spatial attention shifting to fearful faces depends on visual awareness in attentional blink: An ERP study.

It remains unclear to date whether spatial attention towards emotional faces is contingent on, or independent of visual awareness. To investigate this question, a bilateral attentional blink paradigm was used in which lateralised fearful faces were presented at various levels of detectability. Twenty-six healthy participants were presented with two rapid serial streams of human faces, while they attempted to detect a pair of target faces (T2) displayed in close or distant succession of a first target pair (T1). Spatial attention shifting to the T2 fearful faces, indexed by the N2-posterior-contralateral component, was dependent on visual awareness and its magnitude covaried with the visual awareness negativity, a neural marker of awareness at the perceptual level. Additionally, information consolidation in working memory, indexed by the sustained posterior contralateral negativity, positively correlated with the level of visual awareness and spatial attention shifting. These findings demonstrate that spatial attention shifting to fearful faces depends on visual awareness, and these early processes are closely linked to information maintenance in working memory.

Neural activities during the Processing of unattended and unseen emotional faces: a voxel-wise Meta-analysis.

Voxel-wise meta-analyses of task-evoked regional activity were conducted for healthy individuals during the unconscious processing of emotional and neutral faces with an aim to examine whether and how different experimental paradigms influenced brain activation patterns. Studies were categorized into sensory and attentional unawareness paradigms. Thirty-four fMRI studies including 883 healthy participants were identified. Across experimental paradigms, unaware emotional faces elicited stronger activation of the limbic system, striatum, inferior frontal gyrus, insula and the temporal lobe, compared to unaware neutral faces. Crucially, in attentional unawareness paradigms, unattended emotional faces elicited a right-lateralized increased activation (i.e., right amygdala, right temporal pole), suggesting a right hemisphere dominance for processing emotional faces during inattention. By contrast, in sensory unawareness paradigms, unseen emotional faces elicited increased activation of the left striatum, the left amygdala and the right middle temporal gyrus. Additionally, across paradigms, unconsciously processed positive emotions were found associated with more activation in temporal and parietal cortices whereas unconsciously processed negative emotions elicited stronger activation in subcortical regions, compared to neutral faces.

Cognitive and Emotional Determinants of Automatic Perspective Taking in Healthy Adults.

Previous studies using the dot-perspective task postulated that people automatically take into account others' perspective even when it prevents them from achieving their own goals. This human ability may be of key importance for the ascription of mental states and social interactions. The cognitive and emotional determinants of automatic perspective taking (APT) is still matter of debate. To address this issue, we examined the performance in the Samson et al. APT task in 91 healthy adults who underwent a detailed neuropsychological testing including assessment of their general intelligence (Wechsler Adult Intelligence Scale, WAIS), attention and impulsivity (Conners' Continuous Performance Test-II, CPT-II), alexithymia (Toronto Alexithymia Scale, TAS), and measures of affective empathy and explicit theory of mind (Geneva Social Cognition Scale, GeSoCS, and mini-Social cognition and Emotional Assessment, mini-SEA). Univariate and multiple linear regression models (adjusted for age, gender, and education) were used to explore the association between mean reaction times (respectively, mean number of errors) in the APT task, and the CPT-II parameters, WAIS global score (as well as subscale scores), TAS, and GeSoCS and mini-SEA scores. Only the CPT-II parameters were significantly associated with the mean reaction times. Increased omissions, commissions, and detectability as well as hit reaction time standard error in CPT-II were all related to worse performances both in Self and Other conditions. The mean number of errors was negatively associated with the GeSoCS score. Among the variables studied, only CPT-II parameters had a significant impact on egocentric and altercentric interference. Neither global intelligence nor alexithymia have an effect on dot-perspective task performance. The present findings suggest that people with lower attentional resources and increased impulsivity display worse performances in the APT task and are less responsive to both egocentric and altercentric interference.

Spatial attention shifting to emotional faces is contingent on awareness and task relevancy.

The relationship between visual attention and visual awareness has long been hotly debated. There has been limited evidence on whether the neural marker of spatial attention precedes or succeeds that of visual awareness in the processing of emotional faces. The current study aims to investigate the temporal sequence between the electrophysiological signatures of visual awareness (the visual awareness negativity - VAN) and spatial attention (the N2pc), in contexts where emotional faces are task-relevant (Experiment 1) or task-irrelevant (Experiment 2). Fifty-six healthy participants were presented with fearful and neutral faces under different levels of visibility using backward masking. They either performed a face detection task (Experiment 1) or a contrast detection task while ignoring the faces (Experiment 2). Compared to subliminal stimuli, supraliminal stimuli produced more negative ERPs at 170-270 msec and 210-310 msec in Experiments 1 and 2, respectively, identified as the VAN. The P3, a component also frequently considered to reflect awareness, produced a similar effect with larger amplitudes for supraliminal than subliminal stimuli in both experiments. With respect to spatial attention, a significant N2pc was observed in response to fearful faces but only in the supraliminal viewing condition of Experiment 1, in which faces were task-relevant. Crucially, the VAN was found to precede the N2pc in this case. Our results suggest that spatial attention as indexed by the N2pc, is oriented towards fearful faces when they are relevant to participants' task and are consciously processed. Moreover, an early phenomenal stage of awareness, reflected by the VAN, precedes spatial attention shifting to fearful faces.