Source Localization of Early Stages of Face Processing

Microstate Analyses to Study face Processing in Healthy Individuals and Psychiatric Disorders: A Review of ERP Findings

Microstates represent brief periods of quasi-stable electroencephalography (EEG) scalp topography, offering insights into dynamic fluctuations in event-related potential (ERP) topographies. Despite this, there is a lack of a comprehensive systematic overview of microstate findings concerning cognitive face processing. This review aims to summarize ERP findings on face processing using microstate analyses and assess their effectiveness in characterizing face-related neural representations. A literature search was conducted for microstate ERP studies involving healthy individuals and psychiatric populations, utilizing PubMed, Google Scholar, Web of Science, PsychInfo, and Scopus databases. Twenty-two studies were identified, primarily focusing on healthy individuals (n = 16), with a smaller subset examining psychiatric populations (n = 6). The evidence reviewed in this study suggests that various microstates are consistently associated with distinct ERP stages involved in face processing, encompassing the processing of basic visual facial features to more complex functions such as analytical processing, facial recognition, and semantic representations. Furthermore, these studies shed light on atypical attentional neural mechanisms in Autism Spectrum Disorder (ASD), facial recognition deficits among emotional dysregulation disorders, and encoding and semantic dysfunctions in Post-Traumatic Stress Disorder (PTSD). In conclusion, this review underscores the practical utility of ERP microstate analyses in investigating face processing. Methodologies have evolved towards greater automation and data-driven approaches over time. Future research should aim to forecast clinical outcomes and conduct validation studies to directly demonstrate the efficacy of such analyses in inverse space.

Attentional processes in response to emotional facial expressions in adults with retrospectively reported peer victimization of varying severity: Results from an ERP dot-probe study

BACKGROUND

Attentional processes are influenced by both stimulus characteristics and individual factors such as mood or personal experience. Research has suggested that attentional biases to socially relevant stimuli may occur in individuals with a history of peer victimization in childhood and adolescence. Based on this, the present study aimed to examine attentional processes in response to emotional faces at both the behavioral and neurophysiological levels in participants with experiences of peer victimization.

METHODS

In a sample of 60 adult participants with varying severity of retrospectively reported peer victimization in childhood and adolescence, the dot-probe task was administered with angry, disgusted, sad, and happy facial expressions. In addition to behavioral responses, physiological responses (i.e., event-related potentials) were analyzed.

RESULTS

Analyses of mean P100 and P200 amplitudes revealed altered P200 amplitudes in individuals with higher degrees of peer victimization. Higher levels of relational peer victimization were associated with increased P200 amplitudes in response to facial expressions, particularly angry and disgusted facial expressions. Hierarchical regression analyses showed no evidence for an influence of peer victimization experiences on reaction times or P100 amplitudes in response to the different emotions.

CONCLUSION

Cortical findings suggest that individuals with higher levels of peer victimization mobilize more attentional resources when confronted with negative emotional social stimuli. Peer victimization experiences in childhood and adolescence appear to influence cortical processes into adulthood.

Stimulus Inversion and Emotional Expressions Independently Affect Face and Body Perception: An ERP Study

Faces and bodies provide critical cues for social interaction and communication. Their structural encoding depends on configural processing, as suggested by the detrimental effect of stimulus inversion for both faces (i.e., face inversion effect - FIE) and bodies (body inversion effect - BIE). An occipito-temporal negative event-related potential (ERP) component peaking around 170 ms after stimulus onset (N170) is consistently elicited by human faces and bodies and is affected by the inversion of these stimuli. Albeit it is known that emotional expressions can boost structural encoding (resulting in larger N170 components for emotional than for neutral faces), little is known about body emotional expressions. Thus, the current study investigated the effects of different emotional expressions on structural encoding in combination with FIE and BIE. Three ERP components (P1, N170, P2) were recorded using a 128-channel electroencephalogram (EEG) when participants were presented with (upright and inverted) faces and bodies conveying four possible emotions (happiness, sadness, anger, fear) or no emotion (neutral). Results demonstrated that inversion and emotional expressions independently affected the Accuracy and amplitude of all ERP components (P1, N170, P2). In particular, faces showed specific effects of emotional expressions during the structural encoding stage (N170), while P2 amplitude (representing top-down conceptualisation) was modified by emotional body perception. Moreover, the task performed by participants (i.e., implicit vs. explicit processing of emotional information) differently influenced Accuracy and ERP components. These results support integrated theories of visual perception, thus speaking in favour of the functional independence of the two neurocognitive pathways (one for structural encoding and one for emotional expression analysis) involved in social stimuli processing. Results are discussed highlighting the neurocognitive and computational advantages of the independence between the two pathways.

Reduced spatial frequency differentiation and sex-related specificities in fearful face detection in autism: Insights from EEG and the predictive brain model

Face processing relies on predictive processes driven by low spatial frequencies (LSF) that convey coarse information prior to fine information conveyed by high spatial frequencies. However, autistic individuals might have atypical predictive processes, contributing to facial processing difficulties. This may be more normalized in autistic females, who often exhibit better socio-communicational abilities than males. We hypothesized that autistic females would display a more typical coarse-to-fine processing for socio-emotional stimuli compared to autistic males. To test this hypothesis, we asked adult participants (44 autistic, 51 non-autistic) to detect fearful faces among neutral faces, filtered in two orders: from coarse-to-fine (CtF) and from fine-to-coarse (FtC). Results show lower d' values and longer reaction times for fearful detection in autism compared to non-autistic (NA) individuals, regardless of the filtering order. Both groups presented shorter P100 latency after CtF compared to FtC, and larger amplitude for N170 after FtC compared to CtF. However, autistic participants presented a reduced difference in source activity between CtF and FtC in the fusiform. There was also a more spatially spread activation pattern in autistic females compared to NA females. Finally, females had faster P100 and N170 latencies, as well as larger occipital activation for FtC sequences than males, irrespective of the group. Overall, the results do not suggest impaired predictive processes from LSF in autism despite behavioral differences in fear detection. However, they do indicate reduced brain modulation by spatial frequency in autism. In addition, the findings highlight sex differences that warrant consideration in understanding autistic females.

Asymmetries in event-related potentials part 1: A systematic review of face processing studies

The human brain shows distinct lateralized activation patterns for a range of cognitive processes. One such function, which is thought to be lateralized to the right hemisphere (RH), is human face processing. Its importance for social communication and interaction has led to a plethora of studies investigating face processing in health and disease. Temporally highly resolved methods, like event-related potentials (ERPs), allow for a detailed characterization of different processing stages and their specific lateralization patterns. This systematic review aimed at disentangling some of the contradictory findings regarding the RH specialization in face processing focusing on ERP research in healthy participants. Two databases were searched for studies that investigated left and right electrodes while participants viewed (mostly neutral) facial stimuli. The included studies used a variety of different tasks, which ranged from passive viewing to memorizing faces. The final data selection highlights, that strongest lateralization to the RH was found for the N170, especially for right-handed young male participants. Left-handed, female, and older participants showed less consistent lateralization patterns. Other ERP components like the P1, P2, N2, P3, and the N400 were overall less clearly lateralized. The current review highlights that many of the assumed lateralization patterns are less clear than previously thought and that the variety of stimuli, tasks, and EEG setups used, might contribute to the ambiguous findings.

This is me! Neural correlates of self-recognition in 6- to 8-month-old infants

Historically, evidence of self-recognition in development has been associated with the "rouge test"; however, this has been often criticized for providing a reductionist picture of self-conscious behavior. With two event-related potential (ERP) experiments, this study investigated the origin of self-recognition. Six- to eight-month-old infants (42 males and 35 females, predominately White, tested in the UK in 2022-2023) were presented with images of their face, another peer's face, and their mother's face (N = 38, Exp.1), and images of their own face morphed into another peer's face (N = 39, Exp.2). Results showed an enhanced P100 in infants' ERP response to their own face compared to others' faces (Exp.1 only), suggesting the presence of an enhanced attentional mechanism to one own's face as early as 6 months.

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.

Reduced attentional inhibition for peripheral distractors of angry faces under central perceptual load in deaf individuals: evidence from an event-related potentials study

Background

Studies have shown that deaf individuals distribute more attention to the peripheral visual field and exhibit enhanced visual processing for peripheral stimuli relative to hearing individuals. This leads to better detection of peripheral target motion and simple static stimuli in hearing individuals. However, when threatening faces that represent dangerous signals appear as non-targets in the periphery, it remains unclear whether deaf individuals would retain an advantage over hearing individuals in detecting them.

Methods

In this study, 23 deaf and 28 hearing college students were included. A modified perceptual load paradigm and event-related potentials (ERPs) were adopted. In the task, participants were instructed to search for a target letter in a central letter array, while task-irrelevant face distractors (happy, neutral, and angry faces) were simultaneously presented in the periphery while the central perceptual load was manipulated.

Results

Behavioral data showed that angry faces slowed deaf participants' responses to the target while facilitating the responses of hearing participants. At the electrophysiological level, we found modulation of P1 amplitude by central load only in hearing individuals. Interestingly, larger interference from angry face distractors was associated with higher P1 differential amplitude only in deaf individuals. Additionally, the amplitude of N170 for happy face distractors was smaller than that for angry and neutral face distractors in deaf participants.

Conclusion

The present data demonstrates that, despite being under central perceptual load, deaf individuals exhibit less attentional inhibition to peripheral, goal-irrelevant angry faces than hearing individuals. The result may reflect a compensatory mechanism in which, in the absence of auditory alertness to danger, the detection of visually threatening information outside of the current attentional focus has a high priority.

Cognitive Avoidance Is Associated with Decreased Brain Responsiveness to Threat Distractors under High Perceptual Load

Cognitive coping strategies to deal with anxiety-provoking events have an impact on mental and physical health. Dispositional vigilance is characterized by an increased analysis of the threatening environment, whereas cognitive avoidance comprises strategies to inhibit threat processing. To date, functional neuroimaging studies on the neural underpinnings of these coping styles are scarce and have revealed discrepant findings. In the present study, we examined automatic brain responsiveness as a function of coping styles using functional magnetic resonance imaging. We administered a perceptual load paradigm with contemptuous and fearful faces as distractor stimuli in a sample of N = 43 healthy participants. The Mainz Coping Inventory was used to assess cognitive avoidance and vigilance. An association of cognitive avoidance with reduced contempt and fear processing under high perceptual load was observed in a widespread network including the amygdala, thalamus, cingulate gyrus, insula, and frontal, parietal, temporal, and occipital areas. Our findings indicate that the dispositional tendency to divert one's attention away from distressing stimuli is a valuable predictor of diminished automatic neural responses to threat in several cortical and subcortical areas. A reduced processing in brain regions involved in emotion perception and attention might indicate a potential threat resilience associated with cognitive avoidance.

Real-life relevant face perception is not captured by the N170 but reflected in later potentials: A comparison of 2D and virtual reality stimuli

The perception of faces is one of the most specialized visual processes in the human brain and has been investigated by means of the early event-related potential component N170. However, face perception has mostly been studied in the conventional laboratory, i.e., monitor setups, offering rather distal presentation of faces as planar 2D-images. Increasing spatial proximity through Virtual Reality (VR) allows to present 3D, real-life-sized persons at personal distance to participants, thus creating a feeling of social involvement and adding a self-relevant value to the presented faces. The present study compared the perception of persons under conventional laboratory conditions (PC) with realistic conditions in VR. Paralleling standard designs, pictures of unknown persons and standard control images were presented in a PC- and a VR-modality. To investigate how the mechanisms of face perception differ under realistic conditions from those under conventional laboratory conditions, the typical face-specific N170 and subsequent components were analyzed in both modalities. Consistent with previous laboratory research, the N170 lost discriminatory power when translated to realistic conditions, as it only discriminated faces and controls under laboratory conditions. Most interestingly, analysis of the later component [230–420 ms] revealed more differentiated face-specific processing in VR, as indicated by distinctive, stimulus-specific topographies. Complemented by source analysis, the results on later latencies show that face-specific neural mechanisms are applied only under realistic conditions (A video abstract is available in the Supplementary material and via YouTube: https://youtu.be/TF8wiPUrpSY).

Early Influence of Emotional Scenes on the Encoding of Fearful Expressions With Different Intensities: An Event-Related Potential Study

Contextual affective information influences the processing of facial expressions at the relatively early stages of face processing, but the effect of the context on the processing of facial expressions with varying intensities remains unclear. In this study, we investigated the influence of emotional scenes (fearful, happy, and neutral) on the processing of fear expressions at different levels of intensity (high, medium, and low) during the early stages of facial recognition using event-related potential (ERP) technology. EEG data were collected while participants performed a fearful facial expression recognition task. The results showed that (1) the recognition of high-intensity fear expression was higher than that of medium- and low-intensity fear expressions. Facial expression recognition was the highest when faces appeared in fearful scenes. (2) Emotional scenes modulated the amplitudes of N170 for fear expressions with different intensities. Specifically, the N170 amplitude, induced by high-intensity fear expressions, was significantly higher than that induced by low-intensity fear expressions when faces appeared in both neutral and fearful scenes. No significant differences were found between the N170 amplitudes induced by high-, medium-, and low-intensity fear expressions when faces appeared in happy scenes. These results suggest that individuals may tend to allocate their attention resources to the processing of face information when the valence between emotional context and expression conflicts i.e., when the conflict is absent (fear scene and fearful faces) or is low (neutral scene and fearful faces).

The Effect of Task on Object Processing revealed by EEG decoding

Recent studies showed that task demand affects object representations in higher-level visual areas and beyond, but not so much in earlier areas. There are, however, limitations in those studies including the relatively weak manipulation of task due to the use of familiar real-life objects, the low temporal resolution in fMRI, and the emphasis on the amount and not the source of information carried by brain activations. In the current study, observers categorized images of artificial objects in one of two orthogonal dimensions, shape and texture, while their brain activity was recorded with electroencephalogram (EEG). Results showed that object processing along the texture dimension was affected by task demand starting from a relatively late time (320-370ms time window) after image onset. The findings are consistent with the view that task exerts an effect on the later phases of object processing.

Advances in Electrical Source Imaging: A Review of the Current Approaches, Applications and Challenges

Brain source localization has been consistently implemented over the recent years to elucidate complex brain operations, pairing the high temporal resolution of the EEG with the high spatial estimation of the estimated sources. This review paper aims to present the basic principles of Electrical source imaging (ESI) in the context of the recent progress for solving the forward and the inverse problems, and highlight the advantages and limitations of the different approaches. As such, a synthesis of the current state-of-the-art methodological aspects is provided, offering a complete overview of the present advances with regard to the ESI solutions. Moreover, the new dimensions for the analysis of the brain processes are indicated in terms of clinical and cognitive ESI applications, while the prevailing challenges and limitations are thoroughly discussed, providing insights for future approaches that could help to alleviate methodological and technical shortcomings.

Effects of high and low power on the visual encoding of faces

The experience of power is typically associated with social disengagement, yet power has also been shown to facilitate configural visual encoding - a process that supports the initial perception of a human face. To investigate this apparent contradiction, we directly tested whether power influences the visual encoding of faces. Two experiments, using neural and psychophysical assessments, revealed that low power impeded both first-order configural processing (the encoding of a stimulus as a face, assessed by the N170 event-related potential) and second-order configural processing (the encoding of feature distances within configuration, assessed using the face inversion paradigm), relative to high-power and control conditions. Power did not significantly affect facial feature encoding. Results reveal an early and automatic effect of low power on face perception, characterized primarily by diminished face processing. These findings suggest a novel interplay between visual and cognitive processes in power's influence on social behavior.

A systematic review of event-related potentials as outcome measures of attention bias modification

Attention bias modification (ABM) was initially developed with the goal of reducing attentional bias to threat-and subsequently anxious symptoms-in individuals with heightened anxiety. Although controversial, ABM appears to be generally effective in achieving this goal. Yet, the primary outcome measure of ABM (i.e., the reaction time-based differences score) has poor reliability and temporal resolution, which limits the inferences that can be drawn. In contrast, event-related potentials (ERPs) have superior reliability as well as temporal resolution and may therefore be better outcome measures of ABM. In this review, I systematically assess the research using ERPs as outcome measures in ABM protocols. I focus on the extent to which the ERPs modified by ABM represent earlier or later stages of information processing. In addition, I explore the extent to which ABM produces near and/or far transfer of learning effects on ERP measures. The reviewed literature suggests that ERPs are promising outcome measures of ABM. ABM modulates the effects of affective stimuli on posterior visually evoked ERPs (i.e., P1) as well as ERPs at anterior electrodes (i.e., P2, N2, and ERN). Based on the state of the field, several directions for future research are identified.

Do perceptual expertise and implicit racial bias predict early face-sensitive ERP responses?

Studies examining the visual perception of face race have revealed mixed findings regarding the presence or direction of effects on early face-sensitive event-related potential (ERP) components. Few studies have examined how early ERP components are influenced by individual differences in bottom-up and top-down processes involved in face perception, and how such factors might interact to influence early face-sensitive ERP components has yet to be investigated. Thus, the current study examined whether P100, N170, and P200 responses can be predicted by individual differences in own- and other-race face recognition, implicit racial bias, and their interaction. Race effects were observed in the P100, N170, and P200 responses. Other-race face recognition, implicit racial biases, and their interaction explained a significant amount of unique variability in N170 responses when viewing other-race faces. Responses to own-race faces were minimally influenced with only implicit racial bias predicting a significant amount of unique variability in N170 latency when viewing own-race faces. Face recognition, implicit racial bias, or their interaction did not predict P100 responses. The current findings suggest that face recognition abilities and its interaction with implicit racial bias modulate the early stages of other-race face processing.

Configural processing of emotional bodies and faces in patients with attention deficit hyperactivity disorder

Introduction: Attention Deficit Disorder (ADHD) is associated with interpersonal problems and difficulties in inferring other peoples' emotions. Previous research has focused on face processing, mostly in children. Our study investigated configural processing of emotional bodies and faces in adults with ADHD in comparison with healthy controls, analyzing P100, N170 and P250 event-related potentials (ERPs) and relating them to (socio)cognitive functioning. Method: Nineteen patients with ADHD and 25 healthy controls were presented upright and inverted bodies and faces which had to be categorized as neutral, happy or angry while ERPs were recorded. Additionally, sociocognitive and executive functioning was assessed. Results: In ADHD patients relative to controls, recognition of emotions depicted by bodies but not by faces was impaired and P100 amplitudes were enhanced for angry bodies. Furthermore, patients showed enhanced P250 amplitudes in response to both bodies and faces, specifically for happy and neutral emotions. Larger N170 amplitudes to bodies and faces correlated with lower alexithymia scores only in controls, while enhanced P250 amplitudes to both categories were associated with poorer inhibition only in patients. Conclusion: Adults with ADHD show potentially compensatory enhanced semantic processing of emotional bodies and faces, as reflected by increased P250 amplitudes, associated with poorer executive functioning and subtle alterations of emotional and configural processing, as reflected by ERPs.

Time to Face Language: Embodied Mechanisms Underpin the Inception of Face-Related Meanings in the Human Brain

In construing meaning, the brain recruits multimodal (conceptual) systems and embodied (modality-specific) mechanisms. Yet, no consensus exists on how crucial the latter are for the inception of semantic distinctions. To address this issue, we combined electroencephalographic (EEG) and intracranial EEG (iEEG) to examine when nouns denoting facial body parts (FBPs) and nonFBPs are discriminated in face-processing and multimodal networks. First, FBP words increased N170 amplitude (a hallmark of early facial processing). Second, they triggered fast (~100 ms) activity boosts within the face-processing network, alongside later (~275 ms) effects in multimodal circuits. Third, iEEG recordings from face-processing hubs allowed decoding ~80% of items before 200 ms, while classification based on multimodal-network activity only surpassed ~70% after 250 ms. Finally, EEG and iEEG connectivity between both networks proved greater in early (0-200 ms) than later (200-400 ms) windows. Collectively, our findings indicate that, at least for some lexico-semantic categories, meaning is construed through fast reenactments of modality-specific experience.

Brain Processes While Struggling With Evidence Accumulation During Facial Emotion Recognition: An ERP Study

The human brain is tuned to recognize emotional facial expressions in faces having a natural upright orientation. The relative contributions of featural, configural, and holistic processing to decision-making are as yet poorly understood. This study used a diffusion decision model (DDM) of decision-making to investigate the contribution of early face-sensitive processes to emotion recognition from physiognomic features (the eyes, nose, and mouth) by determining how experimental conditions tapping those processes affect early face-sensitive neuroelectric reflections (P100, N170, and P250) of processes determining evidence accumulation at the behavioral level. We first examined the effects of both stimulus orientation (upright vs. inverted) and stimulus type (photographs vs. sketches) on behavior and neuroelectric components (amplitude and latency). Then, we explored the sources of variance common to the experimental effects on event-related potentials (ERPs) and the DDM parameters. Several results suggest that the N170 indicates core visual processing for emotion recognition decision-making: (a) the additive effect of stimulus inversion and impoverishment on N170 latency; and (b) multivariate analysis suggesting that N170 neuroelectric activity must be increased to counteract the detrimental effects of face inversion on drift rate and of stimulus impoverishment on the stimulus encoding component of non-decision times. Overall, our results show that emotion recognition is still possible even with degraded stimulation, but at a neurocognitive cost, reflecting the extent to which our brain struggles to accumulate sensory evidence of a given emotion. Accordingly, we theorize that: (a) the P100 neural generator would provide a holistic frame of reference to the face percept through categorical encoding; (b) the N170 neural generator would maintain the structural cohesiveness of the subtle configural variations in facial expressions across our experimental manipulations through coordinate encoding of the facial features; and (c) building on the previous configural processing, the neurons generating the P250 would be responsible for a normalization process adapting to the facial features to match the stimulus to internal representations of emotional expressions.

Face-sensitive brain responses in the first year of life

Cortical areas in the ventral visual pathway become selectively tuned towards the processing of faces compared to non-face stimuli beginning around 3 months of age and continuing over the first year. Studies using event-related potentials in the EEG (ERPs) have found an ERP component, the N290, that displays specificity for human faces. Other components, such as the P1, P400, and Nc have been studied to a lesser degree in their responsiveness to human faces. However, little is known about the systematic changes in the neural responses to faces during the first year of life, and the localization of these responses in infants' brain. We examined ERP responses to pictures of faces and objects in infants from 4.5 months through 12 months in a cross-sectional study. We investigated the activity of all the components reported to be involved in infant face processing, with particular interest to their amplitude variation and cortical localization. We identified neural regions responsible for the component through the application of cortical source localization methods. We found larger P1 and N290 responses to faces than objects, and these components were localized in the lingual and middle/posterior fusiform gyri, respectively. The amplitude of the P400 was not differentially sensitive to faces over objects. The Nc component was different for faces and objects, was influenced by the infant's attentional state, and localized in medial-anterior brain areas. The implications of these results are discussed in the identification of developmental ERP precursors to face processing.

Neurophysiological evidence for distinct biases in emotional face processing associated with internalizing and externalizing symptoms in children

Attentional bias to threat has been implicated in both internalizing and externalizing disorders. This study utilizes event-related potentials to examine early stages of perceptual attention to threatening (angry or fearful) versus neutral faces among a sample of 200 children ages 6-8 years from a low-income, urban community. Although both internalizing and externalizing symptoms were associated with processing biases, the nature of the bias differed between these two symptom domains. Internalizing symptoms were associated with heightened early attentional selection (P1) and later perceptual processing (P2) of fearful faces. In contrast, externalizing symptoms were associated with reduced early attentional selection (P1) of fearful faces and enhanced perceptual processing (P2) of neutral faces, possibly indicative of a hostile interpretation bias for ambiguous social cues. These results provide insight into the distinct cognitive-affective processes that may contribute to the etiology and maintenance of internalizing and externalizing psychopathology.

Spatiotemporal pattern of appraising social and emotional relevance: Evidence from event-related brain potentials

Social information is particularly relevant for the human species because of its direct link to guiding physiological responses and behavior. Accordingly, extant functional magnetic resonance imaging (fMRI) data suggest that social content may form a unique stimulus dimension. It remains largely unknown, however, how neural activity underlying social (versus nonsocial) information processing temporally unfolds, and how such social information appraisal may interact with the processing of other stimulus characteristics, particularly emotional meaning. Here, we presented complex visual scenes differing in both social (vs. nonsocial) and emotional relevance (positive, negative, neutral) intermixed with scrambled versions of these pictures to N = 24 healthy young adults. Event-related brain potentials (ERPs) to intact pictures were examined for gaining insight to the dynamics of appraisal of both dimensions, implemented within the brain. Our main finding is an early interaction between social and emotional relevance due to enhanced amplitudes of early ERP components to emotionally positive and neutral pictures of social compared to nonsocial content, presumably reflecting rapid allocation of attention and counteracting an overall negativity bias. Importantly, our ERP data show high similarity with previously observed fMRI data using the same stimuli, and source estimations located the ERP effects in overlapping occipitotemporal brain areas. Our novel data suggest that relevance detection may occur already as early as around 100 ms after stimulus onset and may combine relevance checks not only examining intrinsic pleasantness/emotional valence but also social content as a unique, highly relevant stimulus dimension.

Co-localization of theta-band activity and hemodynamic responses during face perception: simultaneous electroencephalography and functional near-infrared spectroscopy recordings

Face-specific neural processes in the human brain have been localized to multiple anatomical structures and associated with diverse and dynamic social functions. The question of how various face-related systems and functions may be bound together remains an active area of investigation. We hypothesize that face processing may be associated with specific frequency band oscillations that serve to integrate distributed face processing systems. Using a multimodal imaging approach, including electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS), simultaneous signals were acquired during face and object picture viewing. As expected for face processing, hemodynamic activity in the right occipital face area (OFA) increased during face viewing compared to object viewing, and in a subset of participants, the expected N170 EEG response was observed for faces. Based on recently reported associations between the theta band and visual processing, we hypothesized that increased hemodynamic activity in a face processing area would also be associated with greater theta-band activity originating in the same area. Consistent with our hypothesis, theta-band oscillations were also localized to the right OFA for faces, whereas alpha- and beta-band oscillations were not. Together, these findings suggest that theta-band oscillations originating in the OFA may be part of the distributed face-specific processing mechanism.

Eye-gaze processing in the broader bipolar phenotype revealed by electrical neuroimaging

Previous studies have documented atypical brain responses to faces in individuals with bipolar disorder (BD) and in their relatives. In view of previous findings of atypical face processing in youths at risk for BD, the aim of this study was to examine whether BD patients and offspring would show differential activation in networks of the social brain when processing eye-gaze. Data from 18 euthymic BD patients and 18 offspring, as well as 36 age-matched healthy controls, were collected using a delayed face-matching paradigm, event related potentials and electrical neuroimaging methods. The P200 component, which is implicated in facial cues decoding, differentiated the BD groups from their age-matched controls. P200 source reconstruction indicates impairments conveyed by eye-contact in a network involved in experiencing others' social intentions in BD patients (supplementary motor cortex, precentral gyrus, inferior parietal lobe), and the engagement of compensatory prefrontal mechanisms for modulating these functions in BD offspring. When viewing faces that had an averted gaze, BD patients and offspring showed a hypo-activation, compared to controls, particularly in regions involved in experiencing others' feelings (post-central gyrus in BD patients / ventral premotor cortex in offspring). Therefore, the neural mechanism for decoding shifts in eye-gaze may be a familial characteristic of BD.

Childhood maltreatment impacts the early stage of facial emotion processing in young adults with negative schizotypy

Childhood maltreatment (CM) is a factor of risk for psychosis and is associated with alterations in facial emotion processing.Negative symptoms of schizophrenia-spectrum disorders are associated with deficits in facial emotion processing, but research findings on schizotypy are mixed. This study examined the early stage of facial emotion processing in young adults with high levels of negative schizotypy (NS) and explored the impact of childhood maltreatment. On the basis of the Social and Physical Anhedonia subscales of the Chapman Psychosis-Proneness Scales, a total of 74 high-NS and 52 low-NS individuals were recruited to complete the Childhood Trauma Questionnaire and the dot-probe task. The P100 and N170 components of event-related potentials were measured to assess the processing of four facial expressions of emotion. The high-NS group showed significantly reduced P100 amplitudes for all facial expressions. Angry and fearful expressions elicited larger N170 amplitudes than disgusted and happy expressions. Happy expressions elicited shorter N170 latencies than disgusted expressions. Compared to the high-NS group without CM, the high-NS group with CM had a longer latency of P100. Individuals with high NS, compared to individuals with low NS, have impaired fundamental visual processing, but intact processing of facial figurations. Childhood maltreatment may be a factor responsible for the pathological state of the visual pathway in high NS group.

The peripheral preview effect with faces: Combined EEG and eye-tracking suggests multiple stages of trans-saccadic predictive and non-predictive processing

The world appears stable despite saccadic eye-movements. One possible explanation for this phenomenon is that the visual system predicts upcoming input across saccadic eye-movements based on peripheral preview of the saccadic target. We tested this idea using concurrent electroencephalography (EEG) and eye-tracking. Participants made cued saccades to peripheral upright or inverted face stimuli that changed orientation (invalid preview) or maintained orientation (valid preview) while the saccade was completed. Experiment 1 demonstrated better discrimination performance and a reduced fixation-locked N170 component (fN170) with valid than with invalid preview, demonstrating integration of pre- and post-saccadic information. Moreover, the early fixation-related potentials (FRP) showed a preview face inversion effect suggesting that some pre-saccadic input was represented in the brain until around 170 ms post fixation-onset. Experiment 2 replicated Experiment 1 and manipulated the proportion of valid and invalid trials to test whether the preview effect reflects context-based prediction across trials. A whole-scalp Bayes factor analysis showed that this manipulation did not alter the fN170 preview effect but did influence the face inversion effect before the saccade. The pre-saccadic inversion effect declined earlier in the mostly invalid block than in the mostly valid block, which is consistent with the notion of pre-saccadic expectations. In addition, in both studies, we found strong evidence for an interaction between the pre-saccadic preview stimulus and the post-saccadic target as early as 50 ms (Experiment 2) or 90 ms (Experiment 1) into the new fixation. These findings suggest that visual stability may involve three temporal stages: prediction about the saccadic target, integration of pre-saccadic and post-saccadic information at around 50-90 ms post fixation onset, and post-saccadic facilitation of rapid categorization.

The inferior occipital gyrus is a major cortical source of the face-evoked N170: Evidence from simultaneous scalp and intracerebral human recordings

The sudden onset of a face image leads to a prominent face-selective response in human scalp electroencephalographic (EEG) recordings, peaking 170 ms after stimulus onset at occipito-temporal (OT) scalp sites: the N170 (or M170 in magnetoencephalography). According to a widely held view, the main cortical source of the N170 lies in the fusiform gyrus (FG), whereas the posteriorly located inferior occipital gyrus (IOG) would rather generate earlier face-selective responses. Here, we report neural responses to upright and inverted faces recorded in a unique patient using multicontact intracerebral electrodes implanted in the right IOG and in the OT sulcus above the right lateral FG (LFG). Simultaneous EEG recordings on the scalp identified the N170 over the right OT scalp region. The latency and amplitude of this scalp N170 were correlated at the single-trial level with the N170 recorded in the lateral IOG, close to the scalp lateral occipital surface. In addition, a positive component maximal around the latency of the N170 (a P170) was prominent above the internal LFG, whereas this region typically generates an N170 (or "N200") over its external/ventral surface. This suggests that electrophysiological responses in the LFG manifest as an equivalent dipole oriented mostly along the vertical axis with likely minimal projection to the lateral OT scalp region. Altogether, these observations provide evidence that the IOG is a major cortical generator of the face-selective scalp N170, qualifying the potential contribution of the FG and questioning a strict serial spatiotemporal organization of the human cortical face network.

Length of Hair Affects P1 and N170 Latencies for Perception of Women's Faces

This study investigated the relationship between length of hair in facial stimuli and latency and amplitude of the P1 and N170 components of event-related potentials during facial perception. Electroencephalography was recorded from 21 Japanese participants (four men, 17 women) who were shown pictures of faces with one of three lengths of hair: long, medium length, or short. In addition, we used both fixed-size and variable-size blocks. In fixed-size blocks, the three types of stimuli were matched to have the same overall size; in variable-size blocks, long hair stimuli were the biggest, medium length hair stimuli were medium sized, and short hair stimuli were the smallest. We analyzed P1 latency and amplitude using two-way (6 × 2) repeated-measures analysis of variance over length of hair and electrode; N170 latency and amplitude were analyzed using three-way (6 × 2 × 2) repeated-measures analysis of variance over length of hair, hemisphere, and electrode. The latency of P1 to faces with short hair in variable-size blocks was significantly longer than that to the other five stimulus types ( p < .01 for four of the other types; p = .083 for medium length hair in variable-size blocks). The latency of N170 to faces with long hair in variable-size blocks was significantly shorter than that to faces with medium length hair and short hair in variable-size blocks ( p = .026 and p = .086, respectively). These results indicate that length of hair influenced P1 and N170 latency, supporting the notion that length of hair is a significant external facial feature. Because long hair attracted participants' attention, there was early perceptual processing of this feature. In contrast, because short hair did not attract attention, perceptual processing of this feature was late.

Cerebral processing of facial emotions in bipolar I and II disorders: An event-related potential study

BACKGROUND

Behavioral results have shown that bipolar disorder patients have impaired recognition of facial emotions, but the detailed information processing of facial emotions in patients with bipolar I (BD I) and II (BD II) disorders remain unknown.

METHODS

We tested the cerebral event-related potentials to the static facial expressions of Neutral, Happiness, Anger and Sadness in 39 adult patients with BD I, 22 BD II, and 54 healthy volunteers. Participants' affective states were measured with the Mood Disorder Questionnaire, the Hypomania Checklist-32, and the Plutchik-van Praag Depression Inventory.

RESULTS

Over-processed right occipitotemporal cortex during N1 time window to Neutral and Happiness, and during P3b window to Sadness were found in BD I; prolonged N1 latencies to Neutral and Happiness, declined P3b amplitude to Sadness, negative correlation between P3b latency to Sadness and depression, and attenuated superior frontal activity during P3b window to Sadness were found in BD II; and the right-side dominance during facial emotion processing were found in both BD I and BD II.

LIMITATIONS

We didn't record the personality traits or medication used in patients, nor included other facial emotions such as fear and disgust.

CONCLUSIONS

When responding to facial emotions, both BD I and BD II showed a right-side processing dominance; BD I displayed enhanced processing in the right occipitotemporal cortex during structural encoding and categorical processing of facial emotions; while BD II displayed generalized impairments, less involvement of superior frontal cortex to negative emotions, and reduced ability to process negative emotions which was associated with depression.

Abnormalities in early visual processes are linked to hypersociability and atypical evaluation of facial trustworthiness: An ERP study with Williams syndrome

Accurate assessment of trustworthiness is fundamental to successful and adaptive social behavior. Initially, people assess trustworthiness from facial appearance alone. These assessments then inform critical approach or avoid decisions. Individuals with Williams syndrome (WS) exhibit a heightened social drive, especially toward strangers. This study investigated the temporal dynamics of facial trustworthiness evaluation in neurotypic adults (TD) and individuals with WS. We examined whether differences in neural activity during trustworthiness evaluation may explain increased approach motivation in WS compared to TD individuals. Event-related potentials were recorded while participants appraised faces previously rated as trustworthy or untrustworthy. TD participants showed increased sensitivity to untrustworthy faces within the first 65-90 ms, indexed by the negative-going rise of the P1 onset (oP1). The amplitude of the oP1 difference to untrustworthy minus trustworthy faces was correlated with lower approachability scores. In contrast, participants with WS showed increased N170 amplitudes to trustworthy faces. The N170 difference to low-high-trust faces was correlated with low approachability in TD and high approachability in WS. The findings suggest that hypersociability associated with WS may arise from abnormalities in the timing and organization of early visual brain activity during trustworthiness evaluation. More generally, the study provides support for the hypothesis that impairments in low-level perceptual processes can have a cascading effect on social cognition.

Early and late cortical responses to directly gazing faces are task dependent

Gender categorisation of human faces is facilitated when gaze is directed toward the observer (i.e., a direct gaze), compared with situations where gaze is averted or the eyes are closed (Macrae, Hood, Milne, Rowe, & Mason, Psychological Science, 13(5), 460-464, 2002). However, the temporal dynamics underlying this phenomenon remain to some extent unknown. Here, we used electroencephalography (EEG) to assess the neural correlates of this effect, focusing on the event-related potential (ERP) components known to be sensitive to gaze perception (i.e., P1, N170, and P3b). We first replicated the seminal findings of Macrae et al. (2002, Experiment 1) regarding facilitated gender discrimination, and subsequently measured the underlying neural responses. Our data revealed an early preferential processing of direct gaze as compared with averted gaze and closed eyes at the P1, which reverberated at the P3b (Experiment 2). Critically, using the same material, we failed to reproduce these effects when gender categorisation was not required (Experiment 3). Taken together, our data confirm that direct gaze enhances the early P1, as well as later cortical responses to face processing, although the effect appears to be task dependent.

Dysfunctional Early Processing of Facial Expressions in Hazardous Drinkers: Evidence from an ERP Study

Chronic alcohol intoxication impairs multiple cognitive functions. According to the dual system model (DSM), the development of alcohol dependence (AD) involves the imbalance between the automatic-affective system and the reflective system. However, the cognitive functions of non-AD hazardous drinkers (HDs) remain unclear. The present study aimed to explore how the HDs process facial expressions differently from the healthy subjects. Sixteen HDs and seventeen control subjects (CSs) completed an emotional working memory (WM) task while the electroencephalogram (EEG) was recorded. We found that there was no significant group difference in behavioral performance between the two groups. In the ERP data, relative to the CSs, the HDs showed delayed latencies of P1 and N170. Moreover, the CSs showed significant differences between the amplitudes of neural/fear and disgust expressions while these differences were insignificant in the HDs. The current results suggest that the main deficits in the processing of facial expression in HDs existed in the early automatic-affective system instead of in the reflective system.

Interactions between the anterior cingulate-insula network and the fronto-parietal network during perceptual decision-making

Information processing in the human brain during cognitively demanding goal-directed tasks is thought to involve several large-scale brain networks, including the anterior cingulate-insula network (aCIN) and the fronto-parietal network (FPN). Recent functional MRI (fMRI) studies have provided clues that the aCIN initiates activity changes in the FPN. However, when and how often these networks interact remains largely unknown to date. Here, we systematically examined the oscillatory interactions between the aCIN and the FPN by using the spectral Granger causality analysis of reconstructed brain source signals from the scalp electroencephalography (EEG) recorded from human participants performing a face-house perceptual categorization task. We investigated how the aCIN and the FPN interact, what the temporal sequence of events in these nodes is, and what frequency bands of information flow bind these nodes in networks. We found that beta band (13-30Hz) and gamma (30-100Hz) bands of interactions are involved between the aCIN and the FPN during decision-making tasks. In gamma band, the aCIN initiated the Granger causal control over the FPN in 25-225 ms timeframe. In beta band, the FPN achieved a control over the aCIN in 225-425 ms timeframe. These band-specific time-dependent Granger causal controls of the aCIN and the FPN were retained for behaviorally harder decision-making tasks. These findings of times and frequencies of oscillatory interactions in the aCIN and FPN provide us new insights into the general neural mechanisms for sensory information-guided, goal-directed behaviors, including perceptual decision-making processes.

Facial Cosmetics Exert a Greater Influence on Processing of the Mouth Relative to the Eyes: Evidence from the N170 Event-Related Potential Component

Cosmetic makeup significantly influences facial perception. Because faces consist of similar physical structures, cosmetic makeup is typically used to highlight individual features, particularly those of the eyes (i.e., eye shadow) and mouth (i.e., lipstick). Though event-related potentials have been utilized to study various aspects of facial processing, the influence of cosmetics on specific ERP components remains unclear. The present study aimed to investigate the relationship between the application of cosmetic makeup and the amplitudes of the P1 and N170 event-related potential components during facial perception tasks. Moreover, the influence of visual perception on N170 amplitude, was evaluated under three makeup conditions: Eye Shadow, Lipstick, and No Makeup. Electroencephalography was used to monitor 17 participants who were exposed to visual stimuli under each these three makeup conditions. The results of the present study subsequently demonstrated that the Lipstick condition elicited a significantly greater N170 amplitude than the No Makeup condition, while P1 amplitude was unaffected by any of the conditions. Such findings indicate that the application of cosmetic makeup alters general facial perception but exerts no influence on the perception of low-level visual features. Collectively, these results support the notion that the application of makeup induces subtle alterations in the processing of facial stimuli, with a particular effect on the processing of specific facial components (i.e., the mouth), as reflected by changes in N170 amplitude.

Face or House Image Perception: Beta and Gamma Bands of Oscillations in Brain Networks Carry Out Decision-Making

Previous functional magnetic resonance imaging studies have consistently shown that perception of visual objects, such as faces and houses, involves distributed brain networks that include the fusiform face area (FFA), parahippocampal place area (PPA), and dorsolateral prefrontal cortex (DLPFC). These regions are commonly observed to be coactivated in BOLD measurements during perception of visual objects. In this study, we aimed to disentangle node-level and network-level activities in millisecond timescale of perception and decision-making in attempts to answer questions about timing and frequency of brain oscillatory activities. We used clear and noisy face-house image categorization tasks and human scalp electroencephalography recordings combined with source reconstruction techniques to study when and how oscillatory activity organizes within the FFA, PPA, and DLPFC. We uncovered the dynamics of two oscillatory networks-beta (13-30 Hz) and gamma (30-100 Hz). In beta band, the node and network activities were enhanced in time frame of 125-250 msec after stimulus onset, the FFA and PPA acted as main outflow hubs and the DLPFC as a main inflow hub, and network activities negatively correlated with behavior measures of noise levels (response times). In gamma band, node and network activities were elevated in time frame of 0-125 msec after stimulus onset, the DLPFC acted as a main outflow hub, and finally network activities were positively correlated with the noise level. These findings broaden our understanding of temporal evolution of node and network features associated with visual perceptual decision-making.

Task-irrelevant fear enhances amygdala-FFG inhibition and decreases subsequent face processing

Facial threat is associated with changes in limbic activity as well as modifications in the cortical face-related N170. It remains unclear if task-irrelevant threat modulates the response to a subsequent facial stimulus, and whether the amygdala's role in early threat perception is independent and direct, or modulatory. In 19 participants, crowds of emotional faces were followed by target faces and a rating task while simultaneous EEG-fMRI were recorded. In addition to conventional analyses, fMRI-informed EEG analyses and fMRI dynamic causal modeling (DCM) were performed. Fearful crowds reduced EEG N170 target face amplitudes and increased responses in a fMRI network comprising insula, amygdala and inferior frontal cortex. Multimodal analyses showed that amygdala response was present ∼60 ms before the right fusiform gyrus-derived N170. DCM indicated inhibitory connections from amygdala to fusiform gyrus, strengthened when fearful crowds preceded a target face. Results demonstrated the suppressing influence of task-irrelevant fearful crowds on subsequent face processing. The amygdala may be sensitive to task-irrelevant fearful crowds and subsequently strengthen its inhibitory influence on face-responsive fusiform N170 generators. This provides spatiotemporal evidence for a feedback mechanism of the amygdala by narrowing attention in order to focus on potential threats.

Double dissociation of configural and featural face processing on P1 and P2 components as a function of spatial attention

Face recognition relies on both configural and featural processing. Previous research has shown that P1 is sensitive to configural face processing, but it is unclear whether any component is sensitive to featural face processing; moreover, if there is such a component, its temporal sequence relative to P1 is unknown. Thus, to avoid confounding physical stimuli differences between configural and featural face processing on ERP components, a spatial attention paradigm was employed by instructing participants to attend an image stream (faces and houses) or an alphanumeric character stream. The interaction between attention and face processing type on P1 and P2 components indicates different mechanisms of configural and featural face processing as a function of spatial attention. The steady-state visual evoked potential (SSVEP) results clearly demonstrated that participants could selectively attend to different streams of information. Importantly, configural face processing elicited a larger posterior P1 (approximately 128 ms) than featural face processing, whereas P2 (approximately 248 ms) was greater for featural than for configural face processing under attended condition. The interaction between attention and face processing type (configural vs. featural) on P1 and P2 components indicates that there are different mechanisms of configural and featural face processing operating as functions of spatial attention. While the P1 result confirms previous findings separating configural and featural face processing, the newly observed P2 finding in the present study extends this separation to a double dissociation. Therefore, configural and featural face processing are modulated differently by spatial attention, and configural face processing precedes featural face processing.

Abnormalities in the Visual Processing of Viewing Complex Visual Stimuli Amongst Individuals With Body Image Concern

Individuals with body dysmorphic disorder (BDD) and clinically concerning body-image concern (BIC) appear to possess abnormalities in the way they perceive visual information in the form of a bias towards local visual processing. As inversion interrupts normal global processing, forcing individuals to process locally, an upright-inverted stimulus discrimination task was used to investigate this phenomenon. We examined whether individuals with nonclinical, yet high levels of BIC would show signs of this bias, in the form of reduced inversion effects (i.e., increased local processing). Furthermore, we assessed whether this bias appeared for general visual stimuli or specifically for appearance-related stimuli, such as faces and bodies. Participants with high-BIC (n = 25) and low-BIC (n = 30) performed a stimulus discrimination task with upright and inverted faces, scenes, objects, and bodies. Unexpectedly, the high-BIC group showed an increased inversion effect compared to the low-BIC group, indicating perceptual abnormalities may not be present as local processing biases, as originally thought. There was no significant difference in performance across stimulus types, signifying that any visual processing abnormalities may be general rather than appearance-based. This has important implications for whether visual processing abnormalities are predisposing factors for BDD or develop throughout the disorder.

The salience network dynamics in perceptual decision-making

Recent neuroimaging studies have demonstrated that the network consisting of the right anterior insula (rAI), left anterior insula (lAI) and dorsal anterior cingulate cortex (dACC) is activated in sensory stimulus-guided goal-directed behaviors. This network is often known as the salience network (SN). When and how a sensory signal enters and organizes within SN before reaching the central executive network including the prefrontal cortices is still a mystery. Previous electrophysiological studies focused on individual nodes of SN, either on dACC or rAI, have reports of conflicting findings of the earliest cortical activity within the network. Functional magnetic resonance imaging (fMRI) studies are not able to answer these questions in the time-scales of human sensory perception and decision-making. Here, using clear and noisy face-house image categorization tasks and human scalp electroencephalography (EEG) recordings combined with source reconstruction techniques, we study when and how oscillatory activity organizes SN during a perceptual decision. We uncovered that the beta-band (13-30Hz) oscillations bound SN, became most active around 100ms after the stimulus onset and the rAI acted as a main outflow hub within SN for easier decision making task. The SN activities (Granger causality measures) were negatively correlated with the decision response time (decision difficulty). These findings suggest that the SN activity precedes the executive control in mediating sensory and cognitive processing to arrive at visual perceptual decisions.

Deficits in Early Stages of Face Processing in Schizophrenia: A Systematic Review of the P100 Component

INTRODUCTION

Schizophrenia is associated with deficits in face and affect recognition, which contribute to broader social functioning deficits. The present aim was to conduct a meta-analysis of early face processing in schizophrenia, as indexed by the P100 event-related potential component.

METHODS

Twelve studies (n = 328 patients with schizophrenia, n = 330 healthy controls) of the P100 component during face processing were evaluated by calculating Cohen's d for each study and overall weighted mean effect size (ES). In additional exploratory analyses, moderating influences of method and design were investigated, and the P100 component during face processing was evaluated based on valence: 5 studies (n = 225 patients, n = 225 controls) included neutral stimuli, 5 studies (n = 225 patients, n = 225 controls) included happy stimuli, and 4 studies (n = 209 patients, n = 209 controls) included fearful stimuli.

RESULTS

The amplitude of the P100 to face stimuli was smaller in patients relative to controls (ES = .41, P < .01). Methodological or design differences did not account for heterogeneity in ES. When split by valence, results indicate smaller P100 in patients relative to control subjects in response to neutral (ES = .32, P < .001) and happy (ES = .21, P < .05) stimuli, whereas there was no difference in response to fearful faces (ES = .09, P > .05).

DISCUSSION

The results indicate that P100 amplitude in response to faces is smaller in patients with schizophrenia, showing that socially relevant visual processing deficits begin earlier in processing than previously suggested. Additionally, the exploratory analyses suggest emotional specificity in these deficits. Ramifications for our understanding of face processing deficits and treatment development are discussed.

Power effects on implicit prejudice and stereotyping: The role of intergroup face processing

Power is thought to increase discrimination toward subordinate groups, yet its effect on different forms of implicit bias remains unclear. We tested whether power enhances implicit racial stereotyping, in addition to implicit prejudice (i.e., evaluative associations), and examined the effect of power on the automatic processing of faces during implicit tasks. Study 1 showed that manipulated high power increased both forms of implicit bias, relative to low power. Using a neural index of visual face processing (the N170 component of the ERP), Study 2 revealed that power affected the encoding of White ingroup vs. Black outgroup faces. Whereas high power increased the relative processing of outgroup faces during evaluative judgments in the prejudice task, it decreased the relative processing of outgroup faces during stereotype trait judgments. An indirect effect of power on implicit prejudice through enhanced processing of outgroup versus ingroup faces suggested a potential link between face processing and implicit bias. Together, these findings demonstrate that power can affect implicit prejudice and stereotyping as well as early processing of racial ingroup and outgroup faces.

Time course of facial emotion processing in women with borderline personality disorder: an ERP study

BACKGROUND

Borderline personality disorder (BPD) is characterized by a negative perception of others. Previous studies have revealed deficits and biases in facial emotion recognition. This study investigates the behavioural and electrophysiological correlates underlying facial emotion processing in individuals with BPD.

METHODS

The present study was conducted between July 2012 and May 2014. In an emotion classification task, unmedicated female patients with BPD as well as healthy women had to classify faces displaying blends of anger and happiness while the electroencephalogram was recorded. We analyzed visual event-related potentials (ERPs) reflecting early (P100), structural (N170) and categorical (P300) facial processing in addition to behavioural responses.

RESULTS

We included 36 women with BPD and 29 controls in our analysis. Patients with BPD were more likely than controls to classify predominantly happy faces as angry. Independent of facial emotion, women with BPD showed enhanced early occipital P100 amplitudes. Additionally, temporo-occipital N170 amplitudes were reduced at right hemispherical electrode sites. Centroparietal P300 amplitudes were reduced particularly for predominantly happy faces and increased for highly angry faces in women with BPD, whereas in healthy volunteers this component was modulated by both angry and happy facial affect.

LIMITATIONS

Our sample included only women, and no clinical control group was investigated.

CONCLUSION

Our findings suggest reduced thresholds for facial anger and deficits in the discrimination of facial happiness in individuals with BPD. This biased perception is associated with alterations in very early visual as well as deficient structural and categorical processing of faces. The current data could help to explain the negative perception of others that may be related to the patients' impairments in interpersonal functioning.

Adaptation Duration Dissociates Category-, Image-, and Person-Specific Processes on Face-Evoked Event-Related Potentials

Several studies demonstrated that face perception is biased by the prior presentation of another face, a phenomenon termed as face-related after-effect (FAE). FAE is linked to a neural signal-reduction at occipito-temporal areas and it can be observed in the amplitude modulation of the early event-related potential (ERP) components. Recently, macaque single-cell recording studies suggested that manipulating the duration of the adaptor makes the selective adaptation of different visual motion processing steps possible. To date, however, only a few studies tested the effects of adaptor duration on the electrophysiological correlates of human face processing directly. The goal of the current study was to test the effect of adaptor duration on the image-, identity-, and generic category-specific face processing steps. To this end, in a two-alternative forced choice familiarity decision task we used five adaptor durations (ranging from 200-5000 ms) and four adaptor categories: adaptor and test were identical images-Repetition Suppression (RS); adaptor and test were different images of the Same Identity (SameID); adaptor and test images depicted Different Identities (DiffID); the adaptor was a Fourier phase-randomized image (No). Behaviorally, a strong priming effect was observed in both accuracy and response times for RS compared with both DiffID and No. The electrophysiological results suggest that rapid adaptation leads to a category-specific modulation of P100, N170, and N250. In addition, both identity and image-specific processes affected the N250 component during rapid adaptation. On the other hand, prolonged (5000 ms) adaptation enhanced, and extended category-specific adaptation processes over all tested ERP components. Additionally, prolonged adaptation led to the emergence of image-, and identity-specific modulations on the N170 and P2 components as well. In other words, there was a clear dissociation among category, identity-, and image-specific processing steps in the case of longer (3500 and 5000 ms) but not for shorter durations (< 3500 ms), reflected in the gradual reduction of N170 and enhancement of P2 in the No, DiffID, SameID, and RS conditions. Our findings imply that by manipulating adaptation duration one can dissociate the various steps of human face processing, reflected in the ERP response.

Meta-analysis of face processing event-related potentials in schizophrenia

BACKGROUND

Schizophrenia is associated with impaired face processing. N170 and N250 are two event-related potentials that have been studied in relation to face processing in schizophrenia, but the results have been mixed. The aim of this article was to conduct a meta-analysis of N170 and N250 in schizophrenia to evaluate trends and resolve the inconsistencies.

METHODS

Twenty-one studies of N170 (n = 438 schizophrenia patients, n = 418 control subjects) and six studies of N250 (n = 149 schizophrenia patients, n = 151 control subjects) were evaluated. Hedges' g was calculated for each study, and the overall weighted mean effect size (ES) was calculated for N170 and N250. Homogeneity of the ES distributions, potential publication bias, and impact of potential moderators were also assessed.

RESULTS

The amplitude of both N170 and N250 to face stimuli was smaller in patients than control subjects (N170 ES = .64; N250 ES = .49; ps < .001). The distributions of the ES were homogeneous (ps > .90), and there was no indication of a publication bias. We found no significant effect of task requirements regarding judgments of the face stimuli. Moreover, we found no significant difference between the ES for N170 and N250.

CONCLUSIONS

Though findings of individual studies have been mixed, the results of the meta-analysis strongly support disruption of N170 and N250 in schizophrenia. The comparable effect sizes across the two waveforms suggest that the well-established behavioral deficit in face emotion processing is mirrored in an underlying neural impairment for processing faces.

Dissociation between the behavioural and electrophysiological effects of the face and body composite illusions

Several studies have reported similarities between perceptual processes underlying face and body perception, particularly emphasizing the importance of configural processes. Differences between the perception of faces and the perception of bodies were observed by means of a manipulation targeting a specific subtype of configural processing: the composite illusion. The composite face illusion describes the fact that two identical top halves of a face are perceived as being different if they are presented with different bottom parts. This effect disappears, if both halves are laterally shifted. Crucially, the effect of misalignment is not observed for bodies. This study aimed to further explore differences in the time course of face and body perception by using the composite effect. The present results replicated behavioural effects illustrating that misalignment affects the perception of faces but not bodies. Thus, face but not body perception relies on holistic processing. However, differences in the time course of the processing of both stimulus categories emerged at the N170 and P200. The pattern of the behavioural data seemed to be related to the P200. Thus, the present data indicate that holistic processes associated with the effect of misalignment might occur 200 ms after stimulus onset.