Reduced pre-attentive threat versus nonthreat signal discrimination in clinically healthy military personnel with recurrent combat exposure history: A preliminary event-related potential (ERP) study

Evidence now suggests that traumatic-stress impacts brain functions even in the absence of acute-onset post-traumatic stress disorder (PTSD) symptoms. These neurophysiological changes have also been suggested to account for increased risks of PTSD symptoms later developing in the aftermath of subsequent trauma. However, surprisingly few studies have explicitly examined brain function dynamics in high-risk populations, such as combat exposed military personnel without diagnosable PTSD. To extend available research, facial expression sensitive N170 event-related potential (ERP) amplitudes were examined in a clinically healthy sample of active service military personnel with recurrent combat exposure history. Consistent with several established theories of delayed-onset PTSD vulnerability, higher N170 amplitudes to backward-masked fearful and neutral facial expressions correlated with higher levels of past combat exposure. Significantly elevated amplitudes to nonthreatening neutral facial expressions also resulted in an absence of normal threat-versus-nonthreat signal processing specificity. While a modest sample size and cross-sectional design are key limitations here, ongoing prospective-longitudinal follow-ups may shed further light on the precise aetiology and prognostic utility of these preliminary findings in the near future.

Using virtual reality to induce multi-trial inattentional blindness despite trial-by-trial measures of awareness

Unconscious processing has been widely examined using diverse and well-controlled methodologies. However, the extent to which these findings are relevant to real-life instances of information processing without awareness is limited. Here, we present a novel inattentional blindness (IB) paradigm in virtual reality (VR). In three experiments, we managed to repeatedly induce IB while participants foveally viewed salient stimuli for prolonged durations. The effectiveness of this paradigm demonstrates the close relationship between top-down attention and subjective experience. Thus, this method provides an ecologically valid setup to examine processing without awareness.

Beyond facial expressions: A systematic review on effects of emotional relevance of faces on the N170

The N170 is the most prominent electrophysiological signature of face processing. While facial expressions reliably modulate the N170, there is considerable variance in N170 modulations by other sources of emotional relevance. Therefore, we systematically review and discuss this research area using different methods to manipulate the emotional relevance of inherently neutral faces. These methods were categorized into (1) existing pre-experimental affective person knowledge (e.g., negative attitudes towards outgroup faces), (2) experimentally instructed affective person knowledge (e.g., negative person information), (3) contingency-based affective learning (e.g., fear-conditioning), or (4) the immediate affective context (e.g., emotional information directly preceding the face presentation). For all categories except the immediate affective context category, the majority of studies reported significantly increased N170 amplitudes depending on the emotional relevance of faces. Furthermore, the potentiated N170 was observed across different attention conditions, supporting the role of the emotional relevance of faces on the early prioritized processing of configural facial information, regardless of low-level differences. However, we identified several open research questions and suggest venues for further research.

Feature-based interaction between masks and target in continuous flash suppression

Continuous flash suppression (CFS) has become one of the most popular tools in the study of visual processing in the absence of conscious awareness. Studies use different kinds of masks, like colorful Mondrians or random noise. Even though the use of CFS is widespread, little is known about some of the underlying neuronal mechanisms, such as the interactions between masks and stimuli. We designed a b-CFS experiment with feature-reduced targets and masks in order to investigate possible effects of feature-similarity or -orthogonality between masks and targets. Masks were pink noise patterns filtered with an orientation band pass to generate a strong directionality. Target stimuli were Gabors varying systematically in their orientational alignment with the masks. We found that stimuli whose orientational alignment was more similar to that of the masks are suppressed significantly longer. This feature-similarity (here: orientation) based enhancement of suppression duration can be overcome by feature orthogonality in another feature dimension (here: color). We conclude that mask-target interactions exist in continuous flash suppression, and the human visual system can use orthogonality within a feature dimension or across feature dimensions to facilitate the breaking of the CFS.

Potentiated early neural responses to fearful faces are not driven by specific face parts

Prioritized processing of fearful compared to neutral faces is reflected in increased amplitudes of components of the event-related potential (ERP). It is unknown whether specific face parts drive these modulations. Here, we investigated the contributions of face parts on ERPs to task-irrelevant fearful and neutral faces using an ERP-dependent facial decoding technique and a large sample of participants (N = 83). Classical ERP analyses showed typical and robust increases of N170 and EPN amplitudes by fearful relative to neutral faces. Facial decoding further showed that the absolute amplitude of these components, as well as the P1, was driven by the low-frequency contrast of specific face parts. However, the difference between fearful and neutral faces was not driven by any specific face part, as supported by Bayesian statistics. Furthermore, there were no correlations between trait anxiety and main effects or interactions. These results suggest that increased N170 and EPN amplitudes to task-irrelevant fearful compared to neutral faces are not driven by specific facial regions but represent a holistic face processing effect.

Can masked gaze and arrow stimuli elicit overt orienting of attention? A registered report

Viewing an averted gaze can elicit saccades towards the corresponding location. Here, the automaticity of this gaze-following behaviour phenomenon was further tested by exploring whether such an effect can be detected in response to briefly-presented masked averted gazes. Participants completed an oculomotor interference task consisting of making leftward/rightward saccades according to a symbolic instruction cue. Crucially, either a task-irrelevant averted-gaze face or an arrow (i.e., a non-social control stimulus) was also presented in different blocks of trials. Faces and arrows were presented for either 1000 ms, or 8 ms and then backward-masked, to reduce the likelihood of conscious processing. Worse oculomotor performance emerged when the saccade direction did not match (vs match) that suggested by the task-irrelevant gaze/arrow stimuli in the unmasked condition. However, in the masked condition, no oculomotor interference occurred for any task-irrelevant stimulus. Results enrich knowledge about boundary conditions for gaze/arrow-driven orienting using ecological attention measures.

Testing stimulus exposure time as the critical factor of increased EPN and LPP amplitudes for fearful faces during perceptual distraction tasks

Fearful facial expressions are prioritized across different information processing stages, as evident in early, intermediate, and late components of event-related brain potentials (ERPs). Recent studies showed that, in contrast to early N170 modulations, mid-latency (Early Posterior Negativity, EPN) and late (Late Positive Potential, LPP) emotional modulations depend on the attended perceptual feature. Nevertheless, several studies reported significant differences between emotional and neutral faces for the EPN or LPP components during distraction tasks. One cause for these conflicting findings might be that when faces are presented sufficiently long, participants attend to task-irrelevant features of the faces. In this registered report, we tested whether the presentation duration of faces is the critical factor for differences between reported emotional modulations during perceptual distraction tasks. To this end, 48 participants were required to discriminate the orientation of lines overlaid onto fearful or neutral faces, while face presentation varied (100 msec, 300 msec, 1,000 msec, 2,000 msec). While participants did not need to pay attention to the faces, we observed main effects of emotion for the EPN and LPP, but no interaction between emotion and presentation duration. Of note, unregistered exploratory tests per presentation duration showed no significant EPN and LPP emotion differences during short durations (100 and 300 msec) but significant differences with longer durations. While the presentation duration seems not to be a critical factor for EPN and LPP emotion effects, future studies are needed to investigate the role of threshold effects and the applied analytic designs to explain conflicting findings in the literature.

Believing and social interactions: effects on bodily expressions and personal narratives

The processes of believing integrate external perceptual information from the environment with internal emotional states and prior experience to generate probabilistic neural representations of events, i.e., beliefs. As these neural representations manifest mostly below the level of a person's conscious awareness, they may inadvertently affect the spontaneous person's bodily expressions and prospective behavior. By yet to be understood mechanisms people can become aware of these representations and reflect upon them. Typically, people can communicate the content of their beliefs as personal statements and can summarize the narratives of others to themselves or to other people. Here, we describe that social interactions may benefit from the consistency between a person's bodily expressions and verbal statements because the person appears authentic and ultimately trustworthy. The transmission of narratives can thus lay the groundwork for social cooperation within and between groups and, ultimately, between communities and nations. Conversely, a discrepancy between bodily expressions and narratives may cause distrust in the addressee(s) and eventually may destroy social bonds.

Enhancing allocation of visual attention with emotional cues presented in two sensory modalities

Background

Responses to a visual target stimulus in an exogenous spatial cueing paradigm are usually faster if cue and target occur in the same rather than in different locations (i.e., valid vs. invalid), although perceptual conditions for cue and target processing are otherwise equivalent. This cueing validity effect can be increased by adding emotional (task-unrelated) content to the cue. In contrast, adding a secondary non-emotional sensory modality to the cue (bimodal), has not consistently yielded increased cueing effects in previous studies. Here, we examined the interplay of bimodally presented cue content (i.e., emotional vs. neutral), by using combined visual-auditory cues. Specifically, the current ERP-study investigated whether bimodal presentation of fear-related content amplifies deployment of spatial attention to the cued location.

Results

A behavioral cueing validity effect occurred selectively in trials in which both aspects of the cue (i.e., face and voice) were related to fear. Likewise, the posterior contra-ipsilateral P1-activity in valid trials was significantly larger when both cues were fear-related than in all other cue conditions. Although the P3a component appeared uniformly increased in invalidly cued trials, regardless of cue content, a positive LPC deflection, starting about 450 ms after target onset, was, again, maximal for the validity contrast in trials associated with bimodal presentation of fear-related cues.

Conclusions

Simultaneous presentation of fear-related stimulus information in the visual and auditory modality appears to increase sustained visual attention (impairing disengagement of attention from the cued location) and to affect relatively late stages of target processing.

Effects of task load, spatial attention, and trait anxiety on neuronal responses to fearful and neutral faces

There is an ongoing debate on how different components of the event-related potential (ERP) to threat-related facial expressions are modulated by attentional conditions and interindividual differences in trait anxiety. In the current study (N = 80), we examined ERPs to centrally presented, task-irrelevant fearful and neutral faces, while participants had to solve a face-unrelated visual task, which differed in difficulty and spatial position. Critically, we used a fixation-controlled experimental design and ensured the spatial attention manipulation by spectral analysis of the EEG. Besides the factors emotion, spatial attention, and perceptual load, we also investigated correlations between trait anxiety and ERPs. While P1 emotion effects were insignificant, the N170 was increased to fearful faces regardless of load and spatial attention conditions. During the EPN time window, a significantly increased negativity for fearful faces was observed only during low load and spatial attention to the face. We found no significant relationship between ERPs and trait anxiety, questioning the hypothesis of a general hypersensitivity toward fearful expressions in anxious individuals. These results show a high resistance of the N170 amplitude increase for fearful faces to spatial attention and task load manipulations. By contrast, the EPN modulation by fearful faces index a resource-dependent stage of the ERP, requiring both spatial attention at the location of faces and low load of the face-irrelevant task.

Do Subliminal Fearful Facial Expressions Capture Attention?

In two experiments, we tested whether fearful facial expressions capture attention in an awareness-independent fashion. In Experiment 1, participants searched for a visible neutral face presented at one of two positions. Prior to the target, a backward-masked and, thus, invisible emotional (fearful/disgusted) or neutral face was presented as a cue, either at target position or away from the target position. If negative emotional faces capture attention in a stimulus-driven way, we would have expected a cueing effect: better performance where fearful or disgusted facial cues were presented at target position than away from the target. However, no evidence of capture of attention was found, neither in behavior (response times or error rates), nor in event-related lateralizations (N2pc). In Experiment 2, we went one step further and used fearful faces as visible targets, too. Thereby, we sought to boost awareness-independent capture of attention by fearful faces. However, still, we found no significant attention-capture effect. Our results show that fearful facial expressions do not capture attention in an awareness-independent way. Results are discussed in light of existing theories.

A Study of Subliminal Emotion Classification Based on Entropy Features

Electroencephalogram (EEG) has been widely utilized in emotion recognition. Psychologists have found that emotions can be divided into conscious emotion and unconscious emotion. In this article, we explore to classify subliminal emotions (happiness and anger) with EEG signals elicited by subliminal face stimulation, that is to select appropriate features to classify subliminal emotions. First, multi-scale sample entropy (MSpEn), wavelet packet energy (E_i), and wavelet packet entropy (WpEn) of EEG signals are extracted. Then, these features are fed into the decision tree and improved random forest, respectively. The classification accuracy with E_i and WpEn is higher than MSpEn, which shows that E_i and WpEn can be used as effective features to classify subliminal emotions. We compared the classification results of different features combined with the decision tree algorithm and the improved random forest algorithm. The experimental results indicate that the improved random forest algorithm attains the best classification accuracy for subliminal emotions. Finally, subliminal emotions and physiological proof of subliminal affective priming effect are discussed.

All-or-none neural mechanisms underlying face categorization: evidence from the N170

Categorization of visual stimuli is an intrinsic aspect of human perception. Whether the cortical mechanisms underlying categorization operate in an all-or-none or graded fashion remains unclear. In this study, we addressed this issue in the context of the face-specific N170. Specifically, we investigated whether N170 amplitudes grade with the amount of face information available in an image, or a full response is generated whenever a face is perceived. We employed linear mixed-effects modeling to inspect the dependency of N170 amplitudes on stimulus properties and duration, and their relationships to participants' subjective perception. Consistent with previous studies, we found a stronger N170 evoked by faces presented for longer durations. However, further analysis with equivalence tests revealed that this duration effect was eliminated when only faces perceived with high confidence were considered. Therefore, previous evidence supporting the graded hypothesis is more likely to be an artifact of mixing heterogeneous "all" and "none" trial types in signal averaging. These results support the hypothesis that the N170 is generated in an all-or-none manner and, by extension, suggest that categorization of faces may follow a similar pattern.

Fast Unconscious Processing of Emotional Stimuli in Early Stages of the Visual Cortex

Several cortical and subcortical brain areas have been reported to be sensitive to the emotional content of subliminal stimuli. However, the timing of these activations remains unclear. Our scope was to detect the earliest cortical traces of emotional unconscious processing of visual stimuli by recording event-related potentials (ERPs) from 43 participants. Subliminal spiders (emotional) and wheels (neutral), sharing similar low-level visual parameters, were presented at two different locations (fixation and periphery). The differential (peak-to-peak) amplitude from CP1 (77 ms from stimulus onset) to C2 (100 ms), two early visual ERP components originated in V1/V2 according to source localization analyses, was analyzed via Bayesian and traditional frequentist analyses. Spiders elicited greater CP1–C2 amplitudes than wheels when presented at fixation. This fast effect of subliminal stimulation—not reported previously to the best of our knowledge—has implications in several debates: 1) The amygdala cannot be mediating these effects, 2) latency of other evaluative structures recently proposed, such as the visual thalamus, is compatible with these results, 3) the absence of peripheral stimuli effects points to a relevant role of the parvocellular visual system in unconscious processing.

Individual differences in serial dependence manifest when sensory uncertainty is high

Perceptual experience in the recent past has been shown to alter subsequent perception. Recently, it has been suggested that this "serial dependence" effect is modulated by sensory uncertainty. In the current study, by overlaying three different levels of visual noise (i.e., no-, low-, or high-noise) on face stimuli, we investigated how serial dependence in face identity perception varies with sensory uncertainty. After learning two facial identities, the faces were combined at various morph levels and participants reported which identity was perceived while noise and noise-free presentations alternated over trials. Results showed that identity perception of noise-free faces was positively biased toward the past when the previous face was noise-free or highly noisy, but not when a low-noise was added. There were considerable individual differences in bias magnitude for trials preceded by high-noise stimuli which reflected individuals' general bias tendencies. When correlated with the other two conditions, a general bias tendency showed a significant relationship with low-noise trials, but not with no-noise trials. This indicates that the bias tendency of individuals manifests more strongly when the sensory information was uncertain. Therefore, the current findings suggest 1) that sensory uncertainty modulates serial dependence in face identity perception and 2) that an individual's general bias tendency interacts with sensory uncertainty to alter perception.

Gender differences in subliminal affective face priming: A high-density ERP study

INTRODUCTION

Subliminal affective priming effects (SAPEs) refer to the phenomenon by which the presentation of an affective prime stimulus influences the subsequent affective evaluation of a target stimulus. Previous studies have reported that unconsciously processed stimuli affect behavioral performance more than consciously processed stimuli. However, the impact of SAPEs on the face-specific N170 component is unclear. We studied how SAPEs for fearful faces affected the N170 for subsequent supraliminal target faces using event-related potentials (ERPs).

METHODS

Japanese adults (n = 44, 20 females) participated in this study. Subliminal prime faces (neutral or fearful) were presented for 17 ms, followed by a backward mask for 283 ms and 800 ms target faces (neutral, emotionally ambiguous, or fearful). 128-channel ERPs were recorded while participants judged the expression of target faces as neutral or fearful. Response rates and response times were also measured for assessing behavioral alterations.

RESULTS

Although the behavioral results revealed no evidence of SAPEs, we found gender-related SAPEs in right N170 amplitude. Specifically, female participants exhibited enhanced right N170 amplitude for emotionally neutral faces primed by fearful faces, while male participants exhibited decreased N170 amplitude in fearful prime trials with fearful target faces. Male participants exhibited significant correlations between N170 amplitude and behavioral response time in the fearful prime-neutral target condition.

CONCLUSIONS

Our ERP results suggest the existence of a gender difference in target-face processing preceded by subliminally presented face stimuli in the right occipito-temporal region.

Dynamic emotional expressions do not modulate responses to gestures

The tendency to imitate the actions of others appears to be a fundamental aspect of human social interaction. Emotional expressions are a particularly salient form of social stimuli (Vuilleumier & Schwartz, 2001) but their relationship to imitative behaviour is currently unclear. In this paper we report the results of five studies which investigated the effect of a target's dynamic emotional stimuli on participants' tendency to respond compatibly to the target's actions. Experiment one examined the effect of dynamic emotional expressions on the automatic imitation of opening and closing hand movements. Experiment two used the same basic paradigm but added gaze direction as an additional factor. Experiment three investigated the effect of dynamic emotional expressions on compatibility responses to handshakes. Experiment four investigated whether dynamic emotional expressions modulated response to valenced social gestures. Finally, experiment five compared the effects of dynamic and static emotional expressions on participants' automatic imitation of finger lifting. Across all five studies we reliably elicited a compatibility effect however, none of the studies found a significant modulating effect of emotional expression. This null effect was also supported by a random effects meta-analysis and a series of Bayesian t-tests. Nevertheless, these results must be caveated by the fact that our studies had limited power to detect effect sizes below d = 0.4. We conclude by situating our findings within the literature, suggesting that the effect of emotional expressions on automatic imitation is, at best, minimal.

Pinpointing the optimal spatial frequency range for automatic neural facial fear processing

Faces convey an assortment of emotional information via low and high spatial frequencies (LSFs and HSFs). However, there is no consensus on the role of particular spatial frequency (SF) information during facial fear processing. Comparison across studies is hampered by the high variability in cut-off values for demarcating the SF spectrum and by differences in task demands. We investigated which SF information is minimally required to rapidly detect briefly presented fearful faces in an implicit and automatic manner, by sweeping through an entire SF range without constraints of predefined cut-offs for LSFs and HSFs. We combined fast periodic visual stimulation with electroencephalography. We presented neutral faces at 6 ​Hz, periodically interleaved every 5th image with a fearful face, allowing us to quantify an objective neural index of fear discrimination at exactly 1.2 ​Hz. We started from a stimulus containing either only very low or very high SFs and gradually increased the SF content by adding higher or lower SF information, respectively, to reach the full SF spectrum over the course of 70 ​s. We found that faces require at least SF information higher than 5.93 cycles per image (cpi) to implicitly differentiate fearful from neutral faces. However, exclusive HSF faces, even in a restricted SF range between 94.82 and 189.63 cpi already carry the critical information to extract the emotional expression of the faces.

The developmental origins of subliminal face processing

Sensitive responding to facial information is of key importance during human social interactions. Research shows that adults glean much information from another person's face without conscious perception, attesting to the robustness of face processing in the service of adaptive social functioning. Until recently, it was unclear whether such subliminal face processing is an outcome of extensive learning, resulting in adult face processing skills, or an early defining feature of human face processing. Here, we review recent research examining the early ontogeny and brain correlates of subliminal face processing, demonstrating that subliminal face processing: (1) emerges during the first year of life; (2) is multifaceted in response to transient (gaze, emotion) and stable (trustworthiness) facial cues; (3) systematically elicits frontal brain responses linked to attention allocation. The synthesized research suggests that subliminal face processing emerges early in human development and thus may play a foundational role during human social interactions. This offers a fresh look at the ontogenetic origins of unconscious face processing and informs theoretical accounts of human sociality.

The optimal spatial noise for continuous flash suppression masking is pink

A basic question in cognitive neuroscience is how sensory stimuli are processed within and outside of conscious awareness. In the past decade, CFS has become the most popular tool for investigating unconscious visual processing, although the exact nature of some of the underlying mechanisms remains unclear. Here, we investigate which kind of random noise is optimal for CFS masking, and whether the addition of visible edges to noise patterns affects suppression duration. We tested noise patterns of various density as well as composite patterns with added edges, and classic Mondrian masks as well as phase scrambled (edgeless) Mondrian masks for comparison. We find that spatial pink noise (1/F noise) achieved the longest suppression of the tested random noises, however classic Mondrian masks are still significantly more effective in terms of suppression duration. Further analysis reveals that global contrast and general spectral similarity between target and mask cannot account for this difference in effectiveness.

Cue Valence Influences the Effects of Cue Uncertainty on ERP Responses to Emotional Events

Individuals often predict consequences, particularly emotional consequences, according to emotional or non-emotional signals conveyed by environmental cues (i.e., emotional and non-emotional cues, respectively). Some of these cues signify the consequences with certainty (i.e., certain cues), whereas others do not (i.e., uncertain cues). Several event-related potential (ERP) studies regarding non-emotional cues have suggested that the effects of cue uncertainty on attention to emotional events occur in both perception and evaluation processes. However, due to the limitations of previous studies, it is unclear what the effects of cue uncertainty would be in an emotional cue condition. Moreover, it is uncertain whether the effects of cue uncertainty are affected by cue valence (i.e., emotional and non-emotional cues). To address these questions, we asked participants to view cues and then to view emotional (positive or negative) pictures. The cues either did or did not indicate the emotional content of the picture. In the emotional cue condition, happy and fearful faces were used as certain cues indicating upcoming positive and negative pictures, respectively, and neutral faces were used as uncertain cues. In the non-emotional cue condition, scrambled faces outlined in red and blue indicated upcoming positive and negative pictures, respectively, and scrambled faces outlined in green served as uncertain cues. The results showed that for negative pictures, ERP responses in a time range between 60 and 1,000 ms were shifted to a more negative direction in a certain condition than in the uncertain condition when the cues were emotional. However, the effect was the reverse for positive pictures. This effect of cue uncertainty was similar in the non-emotional cue—negative condition. In contrast, there was no effect of cue uncertainty in the non-emotional cue—positive condition. Therefore, the findings indicate that cue uncertainty modulates attention toward emotional events when the events are signified by emotional cues. The findings may also suggest that cue valence modulates the effects of cue uncertainty on attention to emotional events.

Belief formation - A driving force for brain evolution

The topic of belief has been neglected in the natural sciences for a long period of time. Recent neuroscience research in non-human primates and humans, however, has shown that beliefs are the neuropsychic product of fundamental brain processes that attribute affective meaning to concrete objects and events, enabling individual goal setting, decision making and maneuvering in the environment. With regard to the involved neural processes they can be categorized as empirical, relational, and conceptual beliefs. Empirical beliefs are about objects and relational beliefs are about events as in tool use and in interactions between subjects that develop below the level of awareness and are up-dated dynamically. Conceptual beliefs are more complex being based on narratives and participation in ritual acts. As neural processes are known to require computational space in the brain, the formation of inceasingly complex beliefs demands extra neural resources. Here, we argue that the evolution of human beliefs is related to the phylogenetic enlargement of the brain including the parietal and medial frontal cortex in humans.

Modulation of face- and emotion-selective ERPs by the three most common types of face image manipulations

In neuroscientific studies, the naturalness of face presentation differs; a third of published studies makes use of close-up full coloured faces, a third uses close-up grey-scaled faces and another third employs cutout grey-scaled faces. Whether and how these methodological choices affect emotion-sensitive components of the event-related brain potentials (ERPs) is yet unclear. Therefore, this pre-registered study examined ERP modulations to close-up full-coloured and grey-scaled faces as well as cutout fearful and neutral facial expressions, while attention was directed to no-face oddballs. Results revealed no interaction of face naturalness and emotion for any ERP component, but showed, however, large main effects for both factors. Specifically, fearful faces and decreasing face naturalness elicited substantially enlarged N170 and early posterior negativity amplitudes and lower face naturalness also resulted in a larger P1.This pattern reversed for the LPP, showing linear increases in LPP amplitudes with increasing naturalness. We observed no interaction of emotion with face naturalness, which suggests that face naturalness and emotion are decoded in parallel at these early stages. Researchers interested in strong modulations of early components should make use of cutout grey-scaled faces, while those interested in a pronounced late positivity should use close-up coloured faces.

Fast Periodic Visual Stimulation EEG Reveals Reduced Neural Sensitivity to Fearful Faces in Children with Autism

We objectively quantified the neural sensitivity of school-aged boys with and without autism spectrum disorder (ASD) to detect briefly presented fearful expressions by combining fast periodic visual stimulation with frequency-tagging electroencephalography. Images of neutral faces were presented at 6 Hz, periodically interleaved with fearful expressions at 1.2 Hz oddball rate. While both groups equally display the face inversion effect and mainly rely on information from the mouth to detect fearful expressions, boys with ASD generally show reduced neural responses to rapid changes in expression. At an individual level, fear discrimination responses predict clinical status with an 83% accuracy. This implicit and straightforward approach identifies subtle deficits that remain concealed in behavioral tasks, thereby opening new perspectives for clinical diagnosis.

Decoding the dynamic representation of facial expressions of emotion in explicit and incidental tasks

Faces transmit a wealth of important social signals. While previous studies have elucidated the network of cortical regions important for perception of facial expression, and the associated temporal components such as the P100, N170 and EPN, it is still unclear how task constraints may shape the representation of facial expression (or other face categories) in these networks. In the present experiment, we used Multivariate Pattern Analysis (MVPA) with EEG to investigate the neural information available across time about two important face categories (expression and identity) when those categories are either perceived under explicit (e.g. decoding facial expression category from the EEG when task is on expression) or incidental task contexts (e.g. decoding facial expression category from the EEG when task is on identity). Decoding of both face categories, across both task contexts, peaked in time-windows spanning 91-170 ms (across posterior electrodes). Peak decoding of expression, however, was not affected by task context whereas peak decoding of identity was significantly reduced under incidental processing conditions. In addition, errors in EEG decoding correlated with errors in behavioral categorization under explicit processing for both expression and identity, however under incidental conditions only errors in EEG decoding of expression correlated with behavior. Furthermore, decoding time-courses and the spatial pattern of informative electrodes showed consistently better decoding of identity under explicit conditions at later-time periods, with weak evidence for similar effects for decoding of expression at isolated time-windows. Taken together, these results reveal differences and commonalities in the processing of face categories under explicit Vs incidental task contexts and suggest that facial expressions are processed to a richer degree under incidental processing conditions, consistent with prior work indicating the relative automaticity by which emotion is processed. Our work further demonstrates the utility in applying multivariate decoding analyses to EEG for revealing the dynamics of face perception.

Dissociating neural signatures of mental state retrodiction and classification based on facial expressions

Posed facial expressions of actors have often been used as stimuli to induce mental state inferences, in order to investigate ‘Theory of Mind’ processes. However, such stimuli make it difficult to determine whether perceivers are using a basic or more elaborated mentalizing strategy. The current study used as stimuli covert recordings of target individuals who viewed various emotional expressions, which caused them to spontaneously mimic these expressions. Perceivers subsequently judged these subtle emotional expressions of the targets: in one condition (‘classification’) participants were instructed to classify the target’s expression (i.e. match it to a sample) and in another condition (‘retrodicting’) participants were instructed to retrodict (i.e. infer which emotional expression the target was viewing). When instructed to classify, participants showed more prevalent activations in event-related brain potentials (ERPs) at earlier and mid-latency ERP components N170, P200 and P300–600. By contrast, when instructed to retrodict participants showed enhanced late frontal and fronto-temporal ERPs (N800–1000), with more sustained activity over the right than the left hemisphere. These findings reveal different cortical processes involved when retrodicting about a facial expression compared to merely classifying it, despite comparable performance on the behavioral task.

How the Dorsolateral Prefrontal Cortex Controls Affective Processing in Absence of Visual Awareness - Insights From a Combined EEG-rTMS Study

The dorsolateral prefrontal cortex (DLPFC) plays a key role in the modulation of affective processing. However, its specific role in the regulation of neurocognitive processes underlying the interplay of affective perception and visual awareness has remained largely unclear. Using a mixed factorial design, this study investigated effects of inhibitory continuous theta-burst stimulation (cTBS) of the right DLPFC (rDLPFC) compared to an Active Control condition on behavioral (N = 48) and electroencephalographic (N = 38) correlates of affective processing in healthy Chinese participants. Event-related potentials (ERPs) in response to passively viewed subliminal and supraliminal negative and neutral natural scenes were recorded before and after cTBS application. We applied minimum-norm approaches to estimate the corresponding neuronal sources. On a behavioral level, we found evidence for reduced emotional interference by, and less negative and aroused ratings of negative supraliminal stimuli following rDLPFC inhibition. We found no evidence for stimulation effects on self-reported mood or the behavioral discrimination of subliminal stimuli. On a neurophysiological level, rDLPFC inhibition relatively enhanced occipito-parietal brain activity for both subliminal and supraliminal negative compared to neutral images (112–268 ms; 320–380 ms). The early onset and localization of these effects suggests that rDLPFC inhibition boosts automatic processes of “emotional attention” independently of visual awareness. Further, our study reveals the first available evidence for a differential influence of rDLPFC inhibition on subliminal versus supraliminal neural emotion processing. Explicitly, our findings indicate that rDLPFC inhibition selectively enhances late (292–360 ms) activity in response to supraliminal negative images. We tentatively suggest that this differential frontal activity likely reflects enhanced awareness-dependent down-regulation of negative scene processing, eventually leading to facilitated disengagement from and less negative and aroused evaluations of negative supraliminal stimuli.

How the visual brain detects emotional changes in facial expressions: Evidence from driven and intrinsic brain oscillations

The processing of facial expressions is often studied using static pictorial cues. Recent work, however, suggests that viewing changing expressions more robustly evokes physiological responses. Here, we examined the sensitivity of steady-state visual evoked potentials and intrinsic oscillatory brain activity to transient emotional changes in facial expressions. Twenty-two participants viewed sequences of grayscale faces periodically turned on and off at a rate of 17.5 Hz, to evoke flicker steady-state visual evoked potentials (ssVEPs) in visual cortex. Each sequence began with a neutral face (flickering for 2290 msec), immediately followed by a face from the same actor (also flickering for 2290 msec) with one of four expressions (happy, angry, fearful, or another neutral expression), followed by the initially presented neutral face (flickering for 1140 msec). The amplitude of the ssVEP and the power of intrinsic brain oscillations were analyzed, comparing the four expression-change conditions. We found a transient perturbation (reduction) of the ssVEP that was more pronounced after the neutral-to-angry change compared to the other conditions, at right posterior sensors. Induced alpha-band (8-13 Hz) power was reduced compared to baseline after each change. This reduction showed a central-occipital topography and was strongest in the subtlest and rarest neutral-to-neutral condition. Thus, the ssVEP indexed involvement of face-sensitive cortical areas in decoding affective expressions, whereas mid-occipital alpha power reduction reflected condition frequency rather than expression-specific processing, consistent with the role of alpha power changes in selective attention.

Identifying and detecting facial expressions of emotion in peripheral vision

Facial expressions of emotion are signals of high biological value. Whilst recognition of facial expressions has been much studied in central vision, the ability to perceive these signals in peripheral vision has only seen limited research to date, despite the potential adaptive advantages of such perception. In the present experiment, we investigate facial expression recognition and detection performance for each of the basic emotions (plus neutral) at up to 30 degrees of eccentricity. We demonstrate, as expected, a decrease in recognition and detection performance with increasing eccentricity, with happiness and surprised being the best recognized expressions in peripheral vision. In detection however, while happiness and surprised are still well detected, fear is also a well detected expression. We show that fear is a better detected than recognized expression. Our results demonstrate that task constraints shape the perception of expression in peripheral vision and provide novel evidence that detection and recognition rely on partially separate underlying mechanisms, with the latter more dependent on the higher spatial frequency content of the face stimulus.

Fear boosts the early neural coding of faces

The rapid extraction of facial identity and emotional expressions is critical for adapted social interactions. These biologically relevant abilities have been associated with early neural responses on the face sensitive N170 component. However, whether all facial expressions uniformly modulate the N170, and whether this effect occurs only when emotion categorization is task-relevant, is still unclear. To clarify this issue, we recorded high-resolution electrophysiological signals while 22 observers perceived the six basic expressions plus neutral. We used a repetition suppression paradigm, with an adaptor followed by a target face displaying the same identity and expression (trials of interest). We also included catch trials to which participants had to react, by varying identity (identity-task), expression (expression-task) or both (dual-task) on the target face. We extracted single-trial Repetition Suppression (stRS) responses using a data-driven spatiotemporal approach with a robust hierarchical linear model to isolate adaptation effects on the trials of interest. Regardless of the task, fear was the only expression modulating the N170, eliciting the strongest stRS responses. This observation was corroborated by distinct behavioral performance during the catch trials for this facial expression. Altogether, our data reinforce the view that fear elicits distinct neural processes in the brain, enhancing attention and facilitating the early coding of faces.

Emotion Processing by ERP Combined with Development and Plasticity

Emotions important for survival and social interaction have received wide and deep investigations. The application of the fMRI technique into emotion processing has obtained overwhelming achievements with respect to the localization of emotion processes. The ERP method, which possesses highly temporal resolution compared to fMRI, can be employed to investigate the time course of emotion processing. The emotional modulation of the ERP component has been verified across numerous researches. Emotions, described as dynamically developing along with the growing age, have the possibility to be enhanced through learning (or training) or to be damaged due to disturbances in growth, which is underlain by the neural plasticity of emotion-relevant nervous systems. And mood disorders with typical symptoms of emotion discordance probably have been caused by the dysfunctional neural plasticity.

Inhibition of Return Is Modulated by Negative Stimuli: Evidence from Subliminal Perception

Inhibition of return (IOR) is considered as a “blindness mechanism” that emotional stimuli have no impact on it. Most previous studies suggested that IOR was not modulated by emotional cues. However, one key question they ignored was that only supraliminal presentation of emotional stimuli was used in their experiments. The present experiment is aimed at exploring the possible interaction between the IOR effect and subliminal emotional process. We manipulated three different kinds of valence strength of negative stimuli (high negative, HN; moderate negative, MN; low negative, LN) which were presented under the subliminal perception level and an event-related potentials (ERPs) recording was adopted. The results showed that, compared to MN and HN, the IOR effect triggered by peripheral cues was more significant for LN with aspects of behavioral and electrophysiological data (a reduction P1 effect, more negative on cued trials than on uncued trials for both early posterior Nd and Nd components). This indicated that IOR can be modulated by emotionally relevant stimuli. The automatic processing that was triggered by subliminally negative stimuli of peripheral cues had an influence on the shifting of spatial attention that was triggered by IOR. These two mechanisms may occur in the perceptual stage simultaneously.

Subliminal Face Emotion Processing: A Comparison of Fearful and Disgusted Faces

Prior research has provided evidence for (1) subcortical processing of subliminal facial expressions of emotion and (2) for the emotion-specificity of these processes. Here, we investigated if this is also true for the processing of the subliminal facial display of disgust. In Experiment 1, we used differently filtered masked prime faces portraying emotionally neutral or disgusted expressions presented prior to clearly visible target faces to test if the masked primes exerted an influence on target processing nonetheless. Whereas we found evidence for subliminal face congruence or priming effects, in particular, reverse priming by low spatial frequencies disgusted face primes, we did not find any support for a subcortical origin of the effect. In Experiment 2, we compared the influence of subliminal disgusted faces with that of subliminal fearful faces and demonstrated a behavioral performance difference between the two, pointing to an emotion-specific processing of the disgusted facial expressions. In both experiments, we also tested for the dependence of the subliminal emotional face processing on spatial attention - with mixed results, suggesting an attention-independence in Experiment 1 but not in Experiment 2 -, and we found perfect masking of the face primes - that is, proof of the subliminality of the prime faces. Based on our findings, we speculate that subliminal facial expressions of disgust could afford easy avoidance of these faces. This could be a unique effect of disgusted faces as compared to other emotional facial displays, at least under the conditions studied here.

Electrophysiological Correlates of Subliminal Perception of Facial Expressions in Individuals with Autistic Traits: A Backward Masking Study

People with Autism spectrum disorder (ASD) show difficulty in social communication, especially in the rapid assessment of emotion in faces. This study examined the processing of emotional faces in typically developing adults with high and low levels of autistic traits (measured using the Autism Spectrum Quotient—AQ). Event-related potentials (ERPs) were recorded during viewing of backward-masked neutral, fearful and happy faces presented under two conditions: subliminal (16 ms, below the level of visual conscious awareness) and supraliminal (166 ms, above the time required for visual conscious awareness). Individuals with low and high AQ differed in the processing of subliminal faces, with the low AQ group showing an enhanced N2 amplitude for subliminal happy faces. Some group differences were found in the condition effects, with the Low AQ showing shorter frontal P3b and N4 latencies for subliminal vs. supraliminal condition. Although results did not show any group differences on the face-specific N170 component, there were shorter N170 latencies for supraliminal vs. subliminal conditions across groups. The results observed on the N2, showing group differences in subliminal emotion processing, suggest that decreased sensitivity to the reward value of social stimuli is a common feature both of people with ASD as well as people with high autistic traits from the normal population.

Response bias-related impairment of early subjective face discrimination in social anxiety disorders: An event-related potential study

Considerable research has shown that social anxiety disorder (SAD) is accompanied by various negative cognitive biases, such as social feedback expectancy bias, memory bias, and interpretation bias. However, whether the memory bias in individuals with SAD is actually a manifestation of response bias, and whether such response bias is associated with deficits in face discrimination, remains unclear. In the present study, we investigated response bias (i.e., a tendency to recognize more negative evaluations) to faces with positive (social acceptance) or negative (social rejection) social evaluations in individuals with SAD and healthy controls (HCs) using event-related potentials (ERPs). Behavioral results revealed significant group differences in response bias in the forced-choice recall task, but no difference in overall memory accuracy. ERP results demonstrated that HCs showed a larger N170 to faces that had rejected them as compared to those that had accepted them, but this effect was not evident in the SAD group. Further analysis showed that response bias was correlated with the ΔN170 (rejected - accepted) amplitude. We concluded that the response bias in individuals with SAD is resulted from impairments in early discrimination of social faces, as reflected by the absent early N170 differentiation effect, which was associated with their combined negative biases.

Autistic traits modulate conscious and nonconscious face perception

Difficulty with emotion perception is a core feature of autism spectrum disorder (ASD) that is also associated with the broader autism phenotype. The current study explored the neural underpinnings of conscious and nonconscious perceptions of affect in typically developing individuals with varying levels of autistic-like traits, as measured by the Autism Quotient (AQ). We investigated the relationship between autistic traits and face processing efficiency using event-related potentials (ERPs). In 20 typically developing adults, we utilized ERPs (the P100, N170, and P300) to measure differences in face processing for emotional faces that were presented either (a) too quickly to reach conscious awareness (16 ms) or (b) slowly enough to be consciously observed (200 ms). All individuals evidenced increased P100 and P300 amplitude and shorter N170 latencies for nonconscious versus consciously presented faces. Individuals with high AQ scores evidenced delayed ERP components. Nonconsciously perceived emotional faces elicited enhanced neural responses regardless of AQ score. Higher levels of autistic traits were associated with inefficient face perception (i.e., longer latency of ERP components). This delay parallels processing delays observed in ASD. These data suggest that inefficient social perception is present in individuals with subclinical levels of social impairment.

Differential Visual Processing of Animal Images, with and without Conscious Awareness

The human visual system can quickly and efficiently extract categorical information from a complex natural scene. The rapid detection of animals in a scene is one compelling example of this phenomenon, and it suggests the automatic processing of at least some types of categories with little or no attentional requirements (Li et al., 2002, 2005). The aim of this study is to investigate whether the remarkable capability to categorize complex natural scenes exist in the absence of awareness, based on recent reports that “invisible” stimuli, which do not reach conscious awareness, can still be processed by the human visual system (Pasley et al., 2004; Williams et al., 2004; Fang and He, 2005; Jiang et al., 2006, 2007; Kaunitz et al., 2011a). In two experiments, we recorded event-related potentials (ERPs) in response to animal and non-animal/vehicle stimuli in both aware and unaware conditions in a continuous flash suppression (CFS) paradigm. Our results indicate that even in the “unseen” condition, the brain responds differently to animal and non-animal/vehicle images, consistent with rapid activation of animal-selective feature detectors prior to, or outside of, suppression by the CFS mask.

Processes of believing: Where do they come from? What are they good for?

Despite the long scholarly discourse in Western theology and philosophy on religion, spirituality, and faith, explanations of what a belief and what believing is are still lacking. Recently, cognitive neuroscience research addressed the human capacity of believing. We present evidence suggesting that believing is a human brain function which results in probabilistic representations with attributes of personal meaning and value and thereby guides individuals’ behavior. We propose that the same mental processes operating on narratives and rituals constitute belief systems in individuals and social groups. Our theoretical model of believing is suited to account for secular and non-secular belief formation.

Processes of believing: Where do they come from? What are they good for?

Despite the long scholarly discourse in Western theology and philosophy on religion, spirituality, and faith, explanations of what a belief and what believing is are still lacking. Recently, cognitive neuroscience research addressed the human capacity of believing. We present evidence suggesting that believing is a human brain function which results in probabilistic representations with attributes of personal meaning and value and thereby guides individuals' behavior. We propose that the same mental processes operating on narratives and rituals constitute belief systems in individuals and social groups. Our theoretical model of believing is suited to account for secular and non-secular belief formation.

Deficits of unconscious emotional processing in patients with major depression: An ERP study

BACKGROUND

Major depressive disorder (MDD) is associated with behavioral and neurobiological evidences of negative bias in unconscious emotional processing. However, little is known about the time course of this deficit. The current study aimed to explore the unconscious processing of emotional facial expressions in MDD patients by means of event-related potentials (ERPs).

METHODS

The ERP responses to subliminally presented happy/neutral/sad faces were recorded in 26 medication-free patients and 26 healthy controls in a backward masking task. Three ERP components were compared between patients and controls.

RESULTS

Detection accuracy was at chance level for both groups, suggesting that the process was performed in the absence of conscious awareness of the emotional stimuli. Robust emotion×group interactions were observed in P1, N170 and P3. Compared with the neutral faces, 1) the patients showed larger P1 for sad and smaller P1 for happy faces; however, the controls showed a completely inverse P1 pattern; 2) the controls exhibited larger N170 in the happy but not in the sad trials, whereas patients had comparable larger N170 amplitudes in sad and happy trials; 3) although both groups exhibited larger P3 for emotional faces, the patients showed a priority for sad trials while the controls showed a priority for happy trials.

CONCLUSION

Our data suggested that negative processing bias exists on the unconscious level in individuals with MDD. The ERP measures indicated that the unconscious emotional processing in MDD patients has a time course of three-stage deflection.

Time for Awareness: The Influence of Temporal Properties of the Mask on Continuous Flash Suppression Effectiveness

Visual processing is not instantaneous, but instead our conscious perception depends on the integration of sensory input over time. In the case of Continuous Flash Suppression (CFS), masks are flashed to one eye, suppressing awareness of stimuli presented to the other eye. One potential explanation of CFS is that it depends, at least in part, on the flashing mask continually interrupting visual processing before the stimulus reaches awareness. We investigated the temporal features of masks in two ways. First, we measured the suppression effectiveness of a wide range of masking frequencies (0-32Hz), using both complex (faces/houses) and simple (closed/open geometric shapes) stimuli. Second, we varied whether the different frequencies were interleaved within blocks or separated in homogenous blocks, in order to see if suppression was stronger or weaker when the frequency remained constant across trials. We found that break-through contrast differed dramatically between masking frequencies, with mask effectiveness following a skewed-normal curve peaking around 6Hz and little or no masking for low and high temporal frequencies. Peak frequency was similar for trial-randomized and block randomized conditions. In terms of type of stimulus, we found no significant difference in peak frequency between the stimulus groups (complex/simple, face/house, closed/open). These findings suggest that temporal factors play a critical role in perceptual awareness, perhaps due to interactions between mask frequency and the time frame of visual processing.

Anxiety sensitivity is associated with attentional bias for pain-related information in healthy children and adolescents

This investigation explored the association between anxiety sensitivity and attentional bias for threatening information in children and adolescents ( N = 40). Participants completed a pictorial version of the visual-probe task, featuring pain-related, health-threat and general-threat images presented for 500 and 1250 ms. Regression analyses revealed significant associations between anxiety sensitivity and attentional bias towards pain-related images presented for 500 ms and between state anxiety and attentional bias towards general-threat images presented for 1250 ms. These results suggest that in children and adolescents, anxiety sensitivity is associated with attentional bias for negative information of personal relevance.

Biological Computation Indexes of Brain Oscillations in Unattended Facial Expression Processing Based on Event-Related Synchronization/Desynchronization

Estimation of human emotions from Electroencephalogram (EEG) signals plays a vital role in affective Brain Computer Interface (BCI). The present study investigated the different event-related synchronization (ERS) and event-related desynchronization (ERD) of typical brain oscillations in processing Facial Expressions under nonattentional condition. The results show that the lower-frequency bands are mainly used to update Facial Expressions and distinguish the deviant stimuli from the standard ones, whereas the higher-frequency bands are relevant to automatically processing different Facial Expressions. Accordingly, we set up the relations between each brain oscillation and processing unattended Facial Expressions by the measures of ERD and ERS. This research first reveals the contributions of each frequency band for comprehension of Facial Expressions in preattentive stage. It also evidences that participants have emotional experience under nonattentional condition. Therefore, the user's emotional state under nonattentional condition can be recognized in real time by the ERD/ERS computation indexes of different frequency bands of brain oscillations, which can be used in affective BCI to provide the user with more natural and friendly ways.

The Impact of Perceptual Load on the Non-Conscious Processing of Fearful Faces

Emotional stimuli can be processed without consciousness. In the current study, we used event-related potentials (ERPs) to assess whether perceptual load influences non-conscious processing of fearful facial expressions. Perceptual load was manipulated using a letter search task with the target letter presented at the fixation point, while facial expressions were presented peripherally and masked to prevent conscious awareness. The letter string comprised six letters (X or N) that were identical (low load) or different (high load). Participants were instructed to discriminate the letters at fixation or the facial expression (fearful or neutral) in the periphery. Participants were faster and more accurate at detecting letters in the low load condition than in the high load condition. Fearful faces elicited a sustained positivity from 250 ms to 700 ms post-stimulus over fronto-central areas during the face discrimination and low-load letter discrimination conditions, but this effect was completely eliminated during high-load letter discrimination. Our findings imply that non-conscious processing of fearful faces depends on perceptual load, and attentional resources are necessary for non-conscious processing.

Reward-associated features capture attention in the absence of awareness: Evidence from object-substitution masking

Reward-associated visual features have been shown to capture visual attention, evidenced in faster and more accurate behavioral performance, as well as in neural responses reflecting lateralized shifts of visual attention to those features. Specifically, the contralateral N2pc event-related-potential (ERP) component that reflects attentional shifting exhibits increased amplitude in response to task-relevant targets containing a reward-associated feature. In the present study, we examined the automaticity of such reward-association effects using object-substitution masking (OSM) in conjunction with MEG measures of visual attentional shifts. In OSM, a visual-search array is presented, with the target item to be detected indicated by a surrounding mask (here, four surrounding squares). Delaying the offset of the target-surrounding four-dot mask relative to the offset of the rest of the target/distracter array disrupts the viewer's awareness of the target (masked condition), whereas simultaneous offsets do not (unmasked condition). Here we manipulated whether the color of the OSM target was or was not of a previously reward-associated color. By tracking reward-associated enhancements of behavior and the N2pc in response to masked targets containing a previously rewarded or unrewarded feature, the automaticity of attentional capture by reward could be probed. We found an enhanced N2pc response to targets containing a previously reward-associated color feature. Moreover, this enhancement of the N2pc by reward did not differ between masking conditions, nor did it differ as a function of the apparent visibility of the target within the masked condition. Overall, these results underscore the automaticity of attentional capture by reward-associated features, and demonstrate the ability of feature-based reward associations to shape attentional capture and allocation outside of perceptual awareness.

Pupillary responses reveal infants' discrimination of facial emotions independent of conscious perception

Sensitive responding to others' emotions is essential during social interactions among humans. There is evidence for the existence of subcortically mediated emotion discrimination processes that occur independent of conscious perception in adults. However, only recently work has begun to examine the development of automatic emotion processing systems during infancy. In particular, it is unclear whether emotional expressions impact infants' autonomic nervous system regardless of conscious perception. We examined this question by measuring pupillary responses while subliminally and supraliminally presenting 7-month-old infants with happy and fearful faces. Our results show greater pupil dilation, indexing enhanced autonomic arousal, in response to happy compared to fearful faces regardless of conscious perception. Our findings suggest that, early in ontogeny, emotion discrimination occurs independent of conscious perception and is associated with differential autonomic responses. This provides evidence for the view that automatic emotion processing systems are an early-developing building block of human social functioning.

Role of the first and second person perspective for control of behaviour: Understanding other people's facial expressions

Humans typically make probabilistic inferences about another person's affective state based on her/his bodily movements such as emotional facial expressions, emblematic gestures and whole body movements. Furthermore, humans deduce tentative predictions about the other person's intentions. Thus, the first person perspective of a subject is supplemented by the second person perspective involving theory of mind and empathy. Neuroimaging investigations have shown that the medial and lateral frontal cortex are critical nodes in the circuits underlying theory of mind, empathy, as well as intention of action. It is suggested that personal perspective taking in social interactions is paradigmatic for the capability of humans to generate probabilistic accounts of the outside world that underlie a person's control of behaviour.

Effects of facial color on the subliminal processing of fearful faces

Recent studies have suggested that both configural information, such as face shape, and surface information is important for face perception. In particular, facial color is sufficiently suggestive of emotional states, as in the phrases: "flushed with anger" and "pale with fear." However, few studies have examined the relationship between facial color and emotional expression. On the other hand, event-related potential (ERP) studies have shown that emotional expressions, such as fear, are processed unconsciously. In this study, we examined how facial color modulated the supraliminal and subliminal processing of fearful faces. We recorded electroencephalograms while participants performed a facial emotion identification task involving masked target faces exhibiting facial expressions (fearful or neutral) and colors (natural or bluish). The results indicated that there was a significant interaction between facial expression and color for the latency of the N170 component. Subsequent analyses revealed that the bluish-colored faces increased the latency effect of facial expressions compared to the natural-colored faces, indicating that the bluish color modulated the processing of fearful expressions. We conclude that the unconscious processing of fearful faces is affected by facial color.