Backward masked fearful faces enhance contralateral occipital cortical activity for visual targets within the spotlight of attention

The effects of yohimbine and hydrocortisone on selective attention to fearful faces: An fMRI study

INTRODUCTION

Selective attention to salient emotional information can enable an advantage in the face of danger. The present study aims to investigate the influence of the stress neuromodulators, norepinephrine and cortisol, on selective attention processes to fearful faces and its neuronal activation.

METHODS AND MATERIALS

We used a randomized, double-blind, placebo-controlled design. 167 healthy men between 18 and 35 years (mean [SD] age: 25.23 [4.24] years) participated in the study. Participants received either: (A) yohimbine (n= 41), (B) hydrocortisone (n = 41), (C) yohimbine and hydrocortisone (n = 42) or (D) placebo only (n= 43) and participated in a dot-probe task with fearful and neutral faces in an fMRI scanner.

RESULTS

We found an attentional bias toward fearful faces across all groups and related neuronal activation in the left cuneus. We did not find any differences between experimental treatment groups in selective attention and its neuronal activation.

DISCUSSION

Our results provide evidence that fearful faces lead to an attentional bias with related neuronal activation in the left cuneus. We did not replicate formerly reported activation in the amygdala, intraparietal sulcus, dorsal anterior cingulate cortex, and thalamus. Suitability of the dot-probe task for fMRI studies and insignificant treatment effects are discussed.

Abnormal hemispheric specialization and inter-hemispheric functional cooperation in generalized anxiety disorder

Abnormal hemispheric specialization and inter-hemispheric interactions may contribute to the pathogenesis of general anxiety disorder (GAD). The current study investigated these abnormalities in GAD patients based on the two analytic approaches and examined whether such abnormalities are correlated with anxiety symptom severity. Seventy-three patients with GAD and 60 matched healthy controls were recruited. All participants completed anxiety symptoms assessment and resting-state functional magnetic resonance imaging (rs-fMRI). The autonomy index (AI) and Connectivity between Functionally Homotopic voxels (CFH) were applied to measure and compared between groups. Compared to controls, patients showed stronger AI in the right middle temporal gyrus (MTG). Seed-based analysis revealed stronger functional connectivity (FC) of the right MTG with both right precuneus and right dorsolateral prefrontal cortex (dlPFC) in patients. Patients also exhibited greater CFH in right anterior cingulate cortex (ACC) but decreased CFH in bilateral postcentral gyrus (PCG) and superior occipital gyrus (SOG). Further there were significant correlations between these regional CFH and anxiety symptoms severity. GAD patients demonstrate right hemispheric specialization and aberrant inter-hemispheric functional cooperation, and abnormal inter-hemispheric coordination is associated with anxiety symptom severity. These findings provide a clue to understanding the neuropathological mechanisms of GAD.

Attentional bias to threat and gray matter volume morphology in high anxious individuals

In a sample of highly anxious individuals, the relationship between gray matter volume brain morphology and attentional bias to threat was assessed. Participants performed a dot-probe task of attentional bias to threat and gray matter volume was acquired from whole brain structural T1-weighted magnetic resonance imaging scans. The results replicate previous findings in unselected samples that elevated attentional bias to threat is linked to greater gray matter volume in the middle frontal gyrus and superior frontal gyrus. In addition, we provide novel evidence that elevated attentional bias to threat is associated with greater gray matter volume in the inferior frontal gyrus, insula, cerebellum, and other distributed regions. Lastly, exploratory analyses provide initial evidence that distinct subregions of the right posterior parietal cortex may contribute to attentional bias in a sex-specific manner. Our results illuminate how differences in gray matter volume morphology relate to attentional bias to threat in anxious individuals. This knowledge could inform neurocognitive models of anxiety-related attentional bias to threat.

Does mobile payment change consumers' perception during payment process? -An ERP study

Innovative payment methods have been getting worldwide attention. Exploring the mechanisms behind consumers' purchase behaviors modulated by different payment methods was critical but challenging. In this paper, we proposed a 2 (payment methods: cash payment vs mobile payment) × 2 (price levels of products: high vs low) Event-Related Potentials (ERPs) experiment to study the difference of cash payment and mobile payment on consumers' purchase intention of products in different price level from a neuroscience perspective. Greater P200 amplitude was found in mobile payment condition, which meant that mobile payment captured more early attention resources than cash. Larger N270 amplitude was found in cash payment condition as the participants had to spend more cognitive resources and struggled more when using cash. Moreover, lower N270 amplitude was found in high-price product condition, which indicated that when there were limited cognitive resources, the affective process played a dominating role. Specifically, buying the high-price products with mobile payment, the consumers would experience the pleasure of consumption more rather than the pain of paying. The study offers insights on the cognitive process of consumers when they pay with different methods.

Enhanced contralateral theta oscillations and N170 amplitudes in occipitotemporal scalp regions underlie attentional bias to fearful faces

Attending toward fearful faces and other threatening stimuli increase the chance of survival. The dot-probe task is a commonly used measure of spatial attention. Event-related potentials (ERPs) have been found to be a reliable measure of attentional bias. The dot-probe literature suggests that posterior contralateral N170 amplitudes are more enhanced by fearful faces compared to ipsilateral amplitudes. However, ERP methods remove non-phase locked frequencies, which provides additional information about neural activity. Specifically, theta oscillations (5-7 Hz) have been linked to attentional processing. The purpose of this study was to examine the relationship between posterior contralateral theta oscillations and N170 amplitudes in the dot-probe task. A modified dot-probe task was used with fear and neutral facial expressions and EEG data was recorded from 33 electrodes. The ERP and time-frequency data were extracted from the P7 and P8 electrodes (left and right occipitotemporal regions). This study found enhanced N170 amplitude and theta oscillations in the electrodes posterior contralateral to the fearful face. Contralateral N170 amplitudes and theta oscillations were related such that greater N170 amplitudes were associated with greater theta oscillations. The results indicated that increased contralateral N170 and theta oscillations are related to each other and underlie attentional bias to fearful faces.

Awareness of Emotional Expressions in Cannabis Users: An Event-Related Potential Study

Cannabis use has been associated with anxiogenic effects when used in low frequency for a short duration, but cannabis can also have anxiogenic effects when used heavily for a long duration. Animal studies have indicated the neurobiological mechanisms related to cannabis and anxiety; however, research has been limited on the related neurocognitive mechanisms. Previous research has indicated that cannabis use is associated with alterations in event-related potentials (ERPs). The purpose of the current study was to examine anxiety related attentional processing of emotional expressions using ERP methods. We used a backward masking paradigm to restrict awareness of facial expressions (i.e., fearful, happy, and neutral). The results indicated that cannabis use was associated with differences in emotional processing. Specifically, the results suggested cannabis users had increased P1 amplitudes toward happy facial expressions compared to fearful and neutral. Additionally, cannabis users seemed to have reduced N170 hemisphere lateralization.

Exploring the fMRI based neural correlates of the dot probe task and its modulation by sex and body odor

The dot probe task implicitly cues attention via emotional information, an effect which is especially pronounced for threat-related cues. However, several questions remain unexplored. The first one is whether chemosignals like the androgen-derivative androstadienone can influence such attentional biases. Second, few studies have addressed sex differences regarding attentional biases. Finally, the neural correlates of these potential behavioral effects based on functional magnetic resonance imaging (fMRI) are not known. In two experiments we aimed to answer these questions. A total of 159 healthy individuals (58 oral-contraceptive-users, 42 luteal women, 59 men) were tested. In experiment 1 (behavioral study) we examined attentional biases behaviorally, while in experiment 2 (fMRI study) the dot probe task was complemented by fMRI. Our results provide robust evidence that in healthy participants fearful but not angry or happy faces lead to a strong general attentional bias. Elucidating the neural basis of this effects points to an early processing advantage in bilateral thalamus for valid compared to invalid cued fear. However, this finding was limited to those participants with the strongest attentional biases and was not linked to behavioral measures. Furthermore, no consistent sex or group differences existed neither did the putative human chemosignal androstadienone reliably modulate attentional biases or change neural processing.

Event-related potentials of attentional bias toward faces in the dot-probe task: A systematic review

The dot-probe task is a common task to assess attentional bias toward different stimuli and how groups differ (e.g., attentional bias in anxiety disorders). However, measuring reaction time has been suggested to be unreliable. Neuroimaging methods such as fMRI were shown to be more reliable in assessing attentional bias, but fMRI has poor temporal resolution and therefore cannot assess timing of attention. ERPs have been used to examine the time course of attentional bias. Although ERP research may be more reliable than reaction time, there have been inconsistencies in the literature. This review systematically searched for articles that used the dot-probe task with facial expressions and measured neural correlates with ERP. We found that some of the inconsistencies might be the cause of methodological differences (e.g., timing of stimuli), differences in emotional expression, and/or sample differences (e.g., sex, age, etc.). Suggestions on how future research could address the issues presented in this review were discussed.

Mechanisms for attentional modulation by threatening emotions of fear, anger, and disgust

Appropriately attending to threatening environmental stimuli is evolutionarily adaptive and crucial for survival. This study revealed that nonconscious attentional modulation of disgust has different behavioral and event-related potential (ERP) patterns, as compared to fear and anger. To facilitate its evolutionary purpose of avoidance, disgust first diverts rather than attracts attention. Accordingly, the N1 was smaller in a validly than in an invalidly disgust-cued condition. Furthermore, the frontal P3a for disgust, anger, and fear was found to be larger in the valid than in the invalid condition, which was interpreted as an involuntary switching of attention toward threat-related events to mobilize cognitive resources for action or defense. On the contrary, the parietal P3b only occurred at the conscious level; the enhanced P3b indicated that more cognitive resources were being allocated toward the task-relevant but previously less attended location, to ensure the effective achievement of task goals. In addition, group comparisons between individuals with low and high disgust sensitivity showed that the ERP differences between the disgust and the anger/fear conditions at the unconscious level may be attributed only to individuals with high disgust sensitivity. These findings, together with previous knowledge of the effects of fear and anger on attention, strengthen our confidence in the two-stage scheme of attentional modulation by threats, which consists of an early stage of bottom-up response scaling of sensory processing (reflected by the P1 and N1) and a later stage of top-down integration and regulation of emotion and behavior (reflected by the P3).

Increased Gray Matter Volume and Resting-State Functional Connectivity in Somatosensory Cortex and their Relationship with Autistic Symptoms in Young Boys with Autism Spectrum Disorder

Autism spectrum disorder (ASD) has been widely recognized as a complex neurodevelopmental disorder. A large number of neuroimaging studies suggest abnormalities in brain structure and function of patients with ASD, but there is still no consistent conclusion. We sought to investigate both of the structural and functional brain changes in 3–7-year-old children with ASD compared with typically developing controls (TDs), and to assess whether these alterations are associated with autistic behavioral symptoms. Firstly, we applied an optimized method of voxel-based morphometry (VBM) analysis on structural magnetic resonance imaging (sMRI) data to assess the differences of gray matter volume (GMV) between 31 autistic boys aged 3–7 and 31 age- and handness-matched male TDs. Secondly, we used clusters with between-group differences as seed regions to generate intrinsic functional connectivity maps based on resting-state functional connectivity magnetic resonance imaging (rs-fcMRI) in order to evaluate the functional impairments induced by structural alterations. Brain-behavior correlations were assessed among GMV, functional connectivity and symptom severity in children with ASD. VBM analyses revealed increased GMV in left superior temporal gyrus (STG) and left postcentral gyrus (PCG) in ASD children, comparing with TDs. Using left PCG as a seed region, ASD children displayed significantly higher positive connectivity with right angular gyrus (AG) and greater negative connectivity with right superior parietal gyrus (SPG) and right superior occipital gyrus (SOG), which were associated with the severity of symptoms in social interaction, communication and self-care ability. We suggest that stronger functional connectivity between left PCG and right AG, SPG, and SOG detected in young boys with ASD may serve as important indicators of disease severity. Our study provided preliminary functional evidence that may underlie impaired higher-order multisensory integration in ASD children.

Neural Activation during Anticipation of Near Pain-Threshold Stimulation among the Pain-Fearful

Fear of pain (FOP) can increase risk for chronic pain and disability but little is known about corresponding neural responses in anticipation of potential pain. In this study, more (10 women, 6 men) and less (7 women, 6 men) pain-fearful groups underwent whole-brain functional magnetic resonance imaging (fMRI) during anticipation of near pain-threshold stimulation. Groups did not differ in the proportion of stimuli judged to be painful but pain-fearful participants reported significantly more state fear prior to stimulus exposure. Within the entire sample, stronger activation was found in several pain perception regions (e.g., bilateral insula, midcingulate cortex (MCC), thalamus, superior frontal gyrus) and visual areas linked to decoding stimulus valences (inferior orbital cortex) during anticipation of "painful" stimuli. Between groups and correlation analyses indicated pain-fearful participants experienced comparatively more activity in regions implicated in evaluating potential threats and processing negative emotions during anticipation (i.e., MCC, mid occipital cortex, superior temporal pole), though group differences were not apparent in most so-called "pain matrix" regions. In sum, trait- and task-based FOP is associated with enhanced responsiveness in regions involved in threat processing and negative affect during anticipation of potentially painful stimulation.

Functional and structural amygdala - anterior cingulate connectivity correlates with attentional bias to masked fearful faces

An attentional bias to threat has been causally related to anxiety. Recent research has linked nonconscious attentional bias to threat with variability in the integrity of the amygdala - anterior cingulate pathway, which sheds light on the neuroanatomical basis for a behavioral precursor to anxiety. However, the extent to which structural variability in amygdala - anterior cingulate integrity relates to the functional connectivity within this pathway and how such functional connectivity may relate to attention bias behavior, remain critical missing pieces of the puzzle. In 15 individuals we measured the structural integrity of the amygdala - prefrontal pathway with diffusion tensor-weighted MRI (magnetic resonance imaging), amygdala-seeded intrinsic functional connectivity to the anterior cingulate, and attentional bias toward backward masked fearful faces with a dot-probe task. We found that greater biases in attention to threat predicted greater levels of uncinate fasciculus integrity, greater positive amygdala - anterior cingulate functional connectivity, and greater amygdala coupling with a broader social perception network including the superior temporal sulcus, tempoparietal junction (TPJ), and somatosensory cortex. Additionally, greater levels of uncinate fasciculus integrity correlated with greater levels of amygdala - anterior cingulate intrinsic functional connectivity. Thus, high bias individuals displayed a heightened degree of amygdala - anterior cingulate connectivity during basal conditions, which we believe predisposes these individuals to focus their attention on signals of threat within their environment.

Neural correlates of affective priming effects based on masked facial emotion: an fMRI study

Affective priming refers to the phenomenon that subliminal presentation of facial emotion biases subsequent evaluation of a neutral object in the direction of the prime. The aim of the present study was to specify the neural correlates of evaluative shifts elicited by facial emotion shown below the threshold of conscious perception. We tested the hypotheses whether the amygdala is involved in negative priming, whereas the nucleus accumbens participates in positive priming. In addition, exploratory whole brain correlation analyses were conducted. During 3T fMRI scanning, pictures of sad, happy, and neutral facial expression masked by neutral faces were presented to 110 healthy adults who had to judge valence of masks on a four-point scale. There was evidence for significant negative priming based on sad faces. A correlation was observed between amygdala activation and negative priming. Activation in medial, middle, and superior frontal and middle temporo-occipital areas, and insula was also associated with negative priming. No significant priming based on happy faces was found. However, nucleus accumbens activation to happy faces correlated with the positive priming score. The present findings confirm that the amygdala but also other brain regions, especially the medial frontal cortex, appear involved in automatically elicited negative evaluative shifts.

Attention as a process of selection, perception as a process of representation, and phenomenal experience as the resulting process of perception being modulated by a dedicated consciousness mechanism

Equivalence of attention and consciousness is disputed and necessity of attentional effects for conscious experience has become questioned. However, the conceptual landscape and interpretations of empirical evidence as related to this issue have remained controversial. Here I present some conceptual distinctions and research strategies potentially useful for moving forward when tackling this issue. Specifically, it is argued that we should carefully differentiate between pre-conscious processes and the processes resulting in phenomenal experience, move the emphasis from studying the effects of attention on the modality-specific and feature-specific perception to studying attentional effects on panmodal universal attributes of whatever conscious experience may be the case, and acknowledge that there is a specialized mechanism for leading to conscious experience of the pre-consciously represented contents autonomous from the mechanisms of perception, attention, memory, and cognitive control.

Acute stress eliminates female advantage in detection of ambiguous negative affect

The human stress response evolved to maximize an individual's probability of survival when threatened. The present study addressed whether physical danger modulates perception of an unrelated ambiguous threat and, if so, to what extent this response is sex- specific. The authors utilized a first-time tandem skydive as a stressor, which had been previously validated as producing a highly-controlled, genuinely stressful environment. In a counter-balanced within-subjects design, participants wore a virtual reality helmet to complete an emotion-identification task during the plane's ascent (stress condition) and in the laboratory (control condition). Participants were presented static male faces morphed between 20-80% aggression, which gradually emerged from degraded images. Using a binary forced-choice design, participants identified each ambiguous face as aggressive or neutral. Results showed that participants characterized emotion more rapidly under stress versus control conditions. Unexpectedly, the results also show that while women were more sensitive to affect ambiguity than men under control conditions, they exhibited a marked decrease in sensitivity equivalent to men while under stress.

Acute Stress Eliminates Female Advantage in Detection of Ambiguous Negative Affect

The human stress response evolved to maximize an individual's probability of survival when threatened. The present study addressed whether physical danger modulates perception of an unrelated ambiguous threat and, if so, to what extent this response is sex-specific. The authors utilized a first-time tandem skydive as a stressor, which had been previously validated as producing a highly-controlled, genuinely stressful environment. In a counter-balanced within-subjects design, participants wore a virtual reality helmet to complete an emotion-identification task during the plane's ascent (stress condition) and in the laboratory (control condition). Participants were presented static male faces morphed between 20–80% aggression, which gradually emerged from degraded images. Using a binary forced-choice design, participants identified each ambiguous face as aggressive or neutral. Results showed that participants characterized emotion more rapidly under stress versus control conditions. Unexpectedly, the results also show that while women were more sensitive to affect ambiguity than men under control conditions, they exhibited a marked decrease in sensitivity equivalent to men while under stress.

Enhanced cardiac and attentional responding to fearful faces in 7-month-old infants

Orienting of attention to emotionally negative stimuli is accompanied by rapid heart rate (HR) deceleration, reflecting enhanced attentional and sensory processing. We studied whether similar emotional modulation of cardiac responding is observed in infants. HR and eye movements were recorded from 7-month-old infants while they observed a fearful or happy face that was flanked after 700 ms by a peripheral distractor for 2000 ms. An attentional bias for fearful faces was indicated by less frequent and longer latency saccades toward the distractors during fearful than happy trials. HR deceleration was significantly larger during fearful than happy trials on which infants did not make a distractor-directed saccade. For trials with a distractor-directed saccade, no difference between fearful and happy faces emerged. Thus, the bias to attend preferentially to fearful faces is accompanied by a concomitant increase in the cardiac orienting response.

Emotional faces capture spatial attention in 5-year-old children

Emotional facial expressions are important social cues that convey salient affective information. Infants, younger children, and adults all appear to orient spatial attention to emotional faces with a particularly strong bias to fearful faces. Yet in young children it is unclear whether or not both happy and fearful faces extract attention. Given that the processing of emotional faces is believed by some to serve an evolutionarily adaptive purpose, attentional biases to both fearful and happy expressions would be expected in younger children. However, the extent to which this ability is present in young children and whether or not this ability is genetically mediated is untested. Therefore, the aims of the current study were to assess the spatial-attentional properties of emotional faces in young children, with a preliminary test of whether this effect was influenced by genetics. Five-year-old twin pairs performed a dot-probe task. The results suggest that children preferentially direct spatial attention to emotional faces, particularly right visual field faces. The results provide support for the notion that the direction of spatial attention to emotional faces serves an evolutionarily adaptive function and may be mediated by genetic mechanisms.