How are emotional facial expressions detected rapidly and accurately? A diffusion model analysis.

Previous psychological studies have shown that people detect emotional facial expressions more rapidly and accurately than neutral facial expressions. However, the cognitive mechanisms underlying the efficient detection of emotional facial expressions remain unclear. To investigate this issue, we used diffusion model analyses to estimate the cognitive parameters of a visual search task in which participants detected faces with normal expressions of anger and happiness and their anti-expressions within a crowd of neutral faces. The anti-expressions were artificially created to control the visual changes of facial features but were usually recognized as emotionally neutral. We tested the hypothesis that the emotional significance of the target's facial expressions modulated the non-decisional time and the drift rate. We also conducted an exploratory investigation of the effect of facial expressions on threshold separation. The results showed that the non-decisional time was shorter, and the drift rate was larger for targets with normal expressions than with anti-expressions. Subjective emotional arousal ratings of facial targets were negatively related to the non-decisional time and positively associated with the drift rate. In addition, the threshold separation was larger for normal expressions than for anti-expressions and positively associated with arousal ratings for facial targets. These results suggest that the efficient detection of emotional facial expressions is accomplished via the faster and more cautious accumulation of emotional information of facial expressions which is initiated more rapidly by enhanced attentional allocation.

The structural neural correlates of atypical facial expression recognition in autism spectrum disorder.

Previous studies have demonstrated that individuals with autism spectrum disorder (ASD) are worse at recognizing facial expressions than are typically developing (TD) individuals. The present study investigated the differences in structural neural correlates of emotion recognition between individuals with and without ASD using voxel-based morphometry (VBM). We acquired structural MRI data from 27 high-functioning adults with ASD and 27 age- and sex-matched TD individuals. The ability to recognize facial expressions was measured using a label-matching paradigm featuring six basic emotions (anger, disgust, fear, happiness, sadness, and surprise). The behavioural task did not find deficits of emotion recognition in ASD after controlling for intellectual ability. However, the VBM analysis for the region of interest showed a positive correlation between the averaged percent accuracy across six basic emotions and the grey matter volume of the right inferior frontal gyrus in TD individuals, but not in individuals with ASD. The VBM for the whole brain region under each emotion condition revealed a positive correlation between the percent accuracy for disgusted faces and the grey matter volume of the left dorsomedial prefrontal cortex in individuals with ASD, but not in TD individuals. The different pattern of correlations suggests that individuals with and without ASD use different processing mechanisms for recognizing others' facial expressions.

Schizotypy is associated with difficulties detecting emotional facial expressions.

People with schizophrenia or subclinical schizotypal traits exhibit impaired recognition of facial expressions. However, it remains unclear whether the detection of emotional facial expressions is impaired in people with schizophrenia or high levels of schizotypy. The present study examined whether the detection of emotional facial expressions would be associated with schizotypy in a non-clinical population after controlling for the effects of IQ, age, and sex. Participants were asked to respond to whether all faces were the same as quickly and as accurately as possible following the presentation of angry or happy faces or their anti-expressions among crowds of neutral faces. Anti-expressions contain a degree of visual change that is equivalent to that of normal emotional facial expressions relative to neutral facial expressions and are recognized as neutral expressions. Normal expressions of anger and happiness were detected more rapidly and accurately than their anti-expressions. Additionally, the degree of overall schizotypy was negatively correlated with the effectiveness of detecting normal expressions versus anti-expressions. An emotion-recognition task revealed that the degree of positive schizotypy was negatively correlated with the accuracy of facial expression recognition. These results suggest that people with high levels of schizotypy experienced difficulties detecting and recognizing emotional facial expressions.

Impairment of emotional expression detection after unilateral medial temporal structure resection.

Detecting emotional facial expressions is an initial and indispensable component of face-to-face communication. Neuropsychological studies on the neural substrates of this process have shown that bilateral amygdala lesions impaired the detection of emotional facial expressions. However, the findings were inconsistent, possibly due to the limited number of patients examined. Furthermore, whether this processing is based on emotional or visual factors of facial expressions remains unknown. To investigate this issue, we tested a group of patients (n = 23) with unilateral resection of medial temporal lobe structures, including the amygdala, and compared their performance under resected- and intact-hemisphere stimulation conditions. The participants were asked to detect normal facial expressions of anger and happiness, and artificially created anti-expressions, among a crowd with neutral expressions. Reaction times for the detection of normal expressions versus anti-expressions were shorter when the target faces were presented to the visual field contralateral to the intact hemisphere (i.e., stimulation of the intact hemisphere; e.g., right visual field for patients with right hemispheric resection) compared with the visual field contralateral to the resected hemisphere (i.e., stimulation of the resected hemisphere). Our findings imply that the medial temporal lobe structures, including the amygdala, play an essential role in the detection of emotional facial expressions, according to the emotional significance of the expressions.

Image database of Japanese food samples with nutrition information.

BACKGROUND: Visual processing of food plays an important role in controlling eating behaviors. Several studies have developed image databases of food to investigate visual food processing. However, few databases include non-Western foods and objective nutrition information on the foods. METHODS: We developed an image database of Japanese food samples that has detailed nutrition information, including calorie, carbohydrate, fat and protein contents. To validate the database, we presented the images, together with Western food images selected from an existing database and had Japanese participants rate their affective (valence, arousal, liking and wanting) and cognitive (naturalness, recognizability and familiarity) appraisals and estimates of nutrition. RESULTS: The results showed that all affective and cognitive appraisals (except arousal) of the Japanese food images were higher than those of Western food. Correlational analyses found positive associations between the objective nutrition information and subjective estimates of the nutrition information, and between the objective calorie/fat content and affective appraisals. CONCLUSIONS: These data suggest that by using our image database, researchers can investigate the visual processing of Japanese food and the relationships between objective nutrition information and the psychological/neural processing of food.

Amygdala activity related to perceived social support.

Perceived social support enhances well-being and prevents stress-related ill-being. A recent structural neuroimaging study reported that the amygdala volume is positively associated with perceived social support. However, it remains unknown how neural activity in this region and functional connectivity (FC) between this and other regions are related to perceived social support. To investigate these issues, resting-state functional magnetic resonance imaging was performed to analyze the fractional amplitude of low-frequency fluctuation (fALFF). Perceived social support was evaluated using the Multidimensional Scale of Perceived Social Support (MSPSS). Lower fALFF values in the bilateral amygdalae were associated with higher MSPSS scores. Additionally, stronger FC between the left amygdala and right orbitofrontal cortex and between the left amygdala and bilateral precuneus were associated with higher MSPSS scores. The present findings suggest that reduced amygdala activity and heightened connectivity between the amygdala and other regions underlie perceived social support and its positive functions.

Atypical Amygdala-Neocortex Interaction During Dynamic Facial Expression Processing in Autism Spectrum Disorder.

Atypical reciprocal social interactions involving emotional facial expressions are a core clinical feature of autism spectrum disorder (ASD). Previous functional magnetic resonance imaging (fMRI) studies have demonstrated that some social brain regions, including subcortical (e.g., amygdala) and neocortical regions (e.g., fusiform gyrus, FG) are less activated during the processing of facial expression stimuli in individuals with ASD. However, the functional networking patterns between the subcortical and cortical regions in processing emotional facial expressions remain unclear. We investigated this issue in ASD (n = 31) and typically developing (TD; n = 31) individuals using fMRI. Participants viewed dynamic facial expressions of anger and happiness and their corresponding mosaic images. Regional brain activity analysis revealed reduced activation of several social brain regions, including the amygdala, in the ASD group compared with the TD group in response to dynamic facial expressions vs. dynamic mosaics (p < 0.05, η p 2 = 0.19). Dynamic causal modeling (DCM) analyses were then used to compare models with forward, backward, and bi-directional effective connectivity between the amygdala and neocortical networks. The results revealed that: (1) the model with effective connectivity from the amygdala to the neocortex best fit the data of both groups; and (2) the same model best accounted for group differences. Coupling parameter (i.e., effective connectivity) analyses showed that the modulatory effects of dynamic facial processing were substantially weaker in the ASD group than in the TD group. These findings suggest that atypical modulation from the amygdala to the neocortex underlies impairment in social interaction involving dynamic facial expressions in individuals with ASD.

Resting-state neural activity and connectivity associated with subjective happiness.

The majority of people throughout the world rate subjective happiness as the top of the important thing in life. A recent structural neuroimaging study exploring neurocognitive mechanisms underlying subjective happiness has suggested that the gray matter volume of the right precuneus is associated with Subjective Happiness Scale (SHS) scores. However, how the neural activity in this region, as well as the neural functional coupling between this and other regions, could be related to SHS scores remains unclear. To investigate these issues, we performed resting-state functional magnetic resonance imaging and analyzed the fractional amplitude of low-frequency fluctuation (fALFF) in participants, whose subjective happiness was evaluated using the SHS. Lower fALFF values in the right precuneus were associated with higher SHS scores. Furthermore, functional connectivity and spectral dynamic causal modeling analyses showed that both functional and effective connectivity of the right precuneus with the right amygdala were positively associated with SHS scores. These findings, together with other evidence on the information-processing functions of these brain regions, suggest the possibility that subjective happiness is associated with a reduction in self-referential mental processes, which are well integrated with emotional processing.

Hunger promotes the detection of high-fat food.

Efficient detection of food is important for an organism's survival. The results of previous experimental studies are consistent with this statement: food is detected in photographs faster than non-food items. Moreover, fat content modulates the speed of food detection. However, it is not known whether such sensitivity to the fat content of food is modulated by participants' internal states. To investigate these issues, we measured reaction times during a visual search task in which participants in fasting and postprandial states detected high-fat food (fast food), low-fat food (Japanese diet), and non-food (kitchen utensils) targets within crowds of non-food distractors (cars). Our results indicate that both hungry and satiated groups detected food targets more rapidly than non-food targets. The high-fat foods were detected more rapidly than low-fat foods in the hungry group, whereas no difference was observed between reaction times when satiated participants detected high-fat and low-fat food targets. These results suggest that food captures our visual attention even when we are satiated, and that fat detection efficiency is heightened when we are hungry.

Electrophysiological correlates of the processing of different self-aspects of handwritten names.

Humans recognize the self in various visual domains, such as faces, names, and motions, as well as in products, such as handwritten letters. Previous studies have indicated that these various domains of self are represented differently in the brain, i.e., domain-specific self-representation. However, it remains unclear whether these differences in brain activation are due to the processing of different visual features or to differential self-processing among the domains, because the studies used different types of visual stimuli. The present study evaluated event-related potentials (ERPs) while participants were presented with their own and others' names generated by the participants themselves or someone else. Therefore, the visual stimuli included two domains of self-related information, name and motor agent, but only one type of stimulus (handwritten names). The ERP results show that the amplitudes of the P250 component (250-330 ms) in the posterior regions were smaller for self-generated handwritten names than for non-self-generated handwritten names. The results also show that the amplitudes of the P300 component (350-500 ms) were larger for the self-name than for the non-self-name. These results suggest domain-specific processing of self-related information regarding the name and agent of handwritten stimuli.

Widespread and lateralized social brain activity for processing dynamic facial expressions.

Dynamic facial expressions of emotions constitute natural and powerful means of social communication in daily life. A number of previous neuroimaging studies have explored the neural mechanisms underlying the processing of dynamic facial expressions, and indicated the activation of certain social brain regions (e.g., the amygdala) during such tasks. However, the activated brain regions were inconsistent across studies, and their laterality was rarely evaluated. To investigate these issues, we measured brain activity using functional magnetic resonance imaging in a relatively large sample (n = 51) during the observation of dynamic facial expressions of anger and happiness and their corresponding dynamic mosaic images. The observation of dynamic facial expressions, compared with dynamic mosaics, elicited stronger activity in the bilateral posterior cortices, including the inferior occipital gyri, fusiform gyri, and superior temporal sulci. The dynamic facial expressions also activated bilateral limbic regions, including the amygdalae and ventromedial prefrontal cortices, more strongly versus mosaics. In the same manner, activation was found in the right inferior frontal gyrus (IFG) and left cerebellum. Laterality analyses comparing original and flipped images revealed right hemispheric dominance in the superior temporal sulcus and IFG and left hemispheric dominance in the cerebellum. These results indicated that the neural mechanisms underlying processing of dynamic facial expressions include widespread social brain regions associated with perceptual, emotional, and motor functions, and include a clearly lateralized (right cortical and left cerebellar) network like that involved in language processing.

Amygdala activation during unconscious visual processing of food.

Hedonic or emotional responses to food have important positive and negative effects on human life. Behavioral studies have shown that hedonic responses to food images are elicited rapidly, even in the absence of conscious awareness of food. Although a number of previous neuroimaging studies investigated neural activity during conscious processing of food images, the neural mechanisms underlying unconscious food processing remain unknown. To investigate this issue, we measured neural activity using functional magnetic resonance imaging while participants viewed food and mosaic images presented subliminally and supraliminally. Conjunction analyses revealed that the bilateral amygdala was more strongly activated in response to food images than to mosaic images under both subliminal and supraliminal conditions. Interaction analyses revealed that the broad bilateral posterior regions, peaking at the posterior fusiform gyrus, were particularly active when participants viewed food versus mosaic images under the supraliminal compared with the subliminal condition. Dynamic causal modeling analyses supported the model in which the subcortical visual pathway from the pulvinar to the amygdala was modulated by food under the subliminal condition; in contrast, the model in which both subcortical and cortical (connecting the primary visual cortex, fusiform gyrus, and the amygdala) visual pathways were modulated by food received the most support under the supraliminal condition. These results suggest the possibility that unconscious hedonic responses to food may exert an effect through amygdala activation via the subcortical visual pathway.

Corticostriatal-limbic correlates of sub-clinical obsessive-compulsive traits.

Obsessive-compulsive (OC) traits such as intrusive worrisome ideas or excessive concerns for threats are frequent in general population (5%-13%). However, the structural neural correlates of the sub-clinical OC traits remain largely unknown. Based on the data of obsessive-compulsive disorder (OCD), we hypothesized that the subcortical and cortical structures, constituting the cortico-striatal-thalamo-cortical circuit (CSTC) and the limbic system, could be associated with OC traits. Here we conducted voxel-based morphometry (VBM) in order to investigate fine grained volume changes of these structures in 49 non-clinical subjects. Analysis of structural covariances of these structures was also conducted. We identified volume changes associated with OC traits in the left putamen and the left amygdala. The results of structural covariance analysis revealed increased covariances in relation to the heightened OC traits between the left putamen to bilateral medial prefrontal cortex and to the left cerebellum, and between the left globus pallidus to the bilateral anterior cingulate cortices. The present finding of volume changes of the corticostriatal-limbic structures may reflect neuroplasticity associated with OC traits. Since the abnormality of these structures were also observed in the clinical OCD, the subclinical subjects with OC traits shared "neuronal obsessive traits" that might precondition OCD at the network level.

Spatiotemporal commonalities of fronto-parietal activation in attentional orienting triggered by supraliminal and subliminal gaze cues: An event-related potential study.

Eye gaze triggers attentional shifts with and without conscious awareness. It remains unclear whether the spatiotemporal patterns of electric neural activity are the same for conscious and unconscious attentional shifts. Thus, the present study recorded event-related potentials (ERPs) and evaluated the neural activation involved in attentional orienting induced by subliminal and supraliminal gaze cues. Nonpredictive gaze cues were presented in the central field of vision, and participants were asked to detect a subsequent peripheral target. The mean reaction time was shorter for congruent gaze cues than for incongruent gaze cues under both presentation conditions, indicating that both types of cues reliably trigger attentional orienting. The ERP analysis revealed that averted versus straight gaze induced greater negative deflection in the bilateral fronto-central and temporal regions between 278 and 344 ms under both supraliminal and subliminal presentation conditions. Supraliminal cues, irrespective of gaze direction, induced a greater negative amplitude than did subliminal cues at the right posterior cortices at a peak of approximately 170 ms and in the 200-300 ms. These results suggest that similar spatial and temporal fronto-parietal activity is involved in attentional orienting triggered by both supraliminal and subliminal gaze cues, although inputs from different visual processing routes (cortical and subcortical regions) may trigger activity in the attentional network.

Impaired detection of happy facial expressions in autism.

The detection of emotional facial expressions plays an indispensable role in social interaction. Psychological studies have shown that typically developing (TD) individuals more rapidly detect emotional expressions than neutral expressions. However, it remains unclear whether individuals with autistic phenotypes, such as autism spectrum disorder (ASD) and high levels of autistic traits (ATs), are impaired in this ability. We examined this by comparing TD and ASD individuals in Experiment 1 and individuals with low and high ATs in Experiment 2 using the visual search paradigm. Participants detected normal facial expressions of anger and happiness and their anti-expressions within crowds of neutral expressions. In Experiment 1, reaction times were shorter for normal angry expressions than for anti-expressions in both TD and ASD groups. This was also the case for normal happy expressions vs. anti-expressions in the TD group but not in the ASD group. Similarly, in Experiment 2, the detection of normal vs. anti-expressions was faster for angry expressions in both groups and for happy expressions in the low, but not high, ATs group. These results suggest that the detection of happy facial expressions is impaired in individuals with ASD and high ATs, which may contribute to their difficulty in creating and maintaining affiliative social relationships.

Homeostatic modulation on unconscious hedonic responses to food.

OBJECTIVE: Hedonic/affective responses to food play a critical role in eating behavior. Previous behavioral studies have shown that hedonic responses to food are elicited consciously and unconsciously. Although the studies also showed that hunger and satiation have a modulatory effect on conscious hedonic responses to food, the effect of these homeostatic states on unconscious hedonic responses to food remains unknown. RESULTS: We investigated unconscious hedonic responses to food in hungry and satiated participants using the subliminal affective priming paradigm. Food images or corresponding mosaic images were presented in the left or right peripheral visual field during 33 ms. Then photographs of target faces with emotionally neutral expressions were presented, and the participants evaluated their preference for the faces. Additionally, daily eating behaviors were assessed using questionnaires. Preference for the target faces was increased by food images relative to the mosaics in the hungry, but not the satiated, state. The difference in preference ratings between the food and mosaic conditions was positively correlated with the tendency for external eating in the hungry, but not the satiated, group. Our findings suggest that homeostatic states modulate unconscious hedonic responses to food and that this phenomenon is related to daily eating behaviors.

Gray matter volumes of early sensory regions are associated with individual differences in sensory processing.

Sensory processing (i.e., the manner in which the nervous system receives, modulates, integrates, and organizes sensory stimuli) is critical when humans are deciding how to react to environmental demands. Although behavioral studies have shown that there are stable individual differences in sensory processing, the neural substrates that implement such differences remain unknown. To investigate this issue, structural magnetic resonance imaging scans were acquired from 51 healthy adults and individual differences in sensory processing were assessed using the Sensory Profile questionnaire (Brown et al.: Am J Occup Ther 55 (2001) 75-82). There were positive relationships between the Sensory Profile modality-specific subscales and gray matter volumes in the primary or secondary sensory areas for the visual, auditory, touch, and taste/smell modalities. Thus, the present results suggest that individual differences in sensory processing are implemented by the early sensory regions. Hum Brain Mapp 38:6206-6217, 2017. © 2017 Wiley Periodicals, Inc.

Reduced Gray Matter Volume in the Social Brain Network in Adults with Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by behavioral impairment in social interactions. Although theoretical and empirical evidence suggests that impairment in the social brain network could be the neural underpinnings of ASD, previous structural magnetic resonance imaging (MRI) studies in adults with ASD have not provided clear support for this, possibly due to confounding factors, such as language impairments. To further explore this issue, we acquired structural MRI data and analyzed gray matter volume in adults with ASD (n = 36) who had no language impairments (diagnosed with Asperger's disorder or pervasive developmental disorder not otherwise specified, with symptoms milder than those of Asperger's disorder), had no comorbidity, and were not taking medications, and in age- and sex-matched typically developing (TD) controls (n = 36). Univariate voxel-based morphometry analyses revealed that regional gray matter volume was lower in the ASD than in the control group in several brain regions, including the right inferior occipital gyrus, left fusiform gyrus, right middle temporal gyrus, bilateral amygdala, right inferior frontal gyrus, right orbitofrontal cortex, and left dorsomedial prefrontal cortex. A multivariate approach using a partial least squares (PLS) method showed that these regions constituted a network that could be used to discriminate between the ASD and TD groups. A PLS discriminant analysis using information from these regions showed high accuracy, sensitivity, specificity, and precision (>80%) in discriminating between the groups. These results suggest that reduced gray matter volume in the social brain network represents the neural underpinnings of behavioral social malfunctioning in adults with ASD.

Putamen Volume is Negatively Correlated with the Ability to Recognize Fearful Facial Expressions.

Findings of previous functional magnetic resonance imaging (MRI) and neuropsychological studies have suggested that specific aspects of the basal ganglia, particularly the putamen, are involved in the recognition of emotional facial expressions. However, it remains unknown whether variations in putamen structure reflect individual differences in the ability to recognize facial expressions. Thus, the present study assessed the putamen volumes and shapes of 50 healthy Japanese adults using structural MRI scans and evaluated the ability of participants to recognize facial expressions associated with six basic emotions: anger, disgust, fear, happiness, sadness, and surprise. The volume of the bilateral putamen was negatively associated with the recognition of fearful faces, and the local shapes of both the anterior and posterior subregions of the bilateral putamen, which are thought to support cognitive/affective and motor processing, respectively, exhibited similar negative relationships with the recognition of fearful expressions. These results suggest that individual differences in putamen structure can predict the ability to recognize fearful facial expressions in others. Additionally, these findings indicate that cognitive/affective and motor processing underlie this process.

Fat Content Modulates Rapid Detection of Food: A Visual Search Study Using Fast Food and Japanese Diet.

Rapid detection of food is crucial for the survival of organisms. However, previous visual search studies have reported discrepant results regarding the detection speeds for food vs. non-food items; some experiments showed faster detection of food than non-food, whereas others reported null findings concerning any speed advantage for the detection of food vs. non-food. Moreover, although some previous studies showed that fat content can affect visual attention for food, the effect of fat content on the detection of food remains unclear. To investigate these issues, we measured reaction times (RTs) during a visual search task in which participants with normal weight detected high-fat food (i.e., fast food), low-fat food (i.e., Japanese diet), and non-food (i.e., kitchen utensils) targets within crowds of non-food distractors (i.e., cars). Results showed that RTs for food targets were shorter than those for non-food targets. Moreover, the RTs for high-fat food were shorter than those for low-fat food. These results suggest that food is more rapidly detected than non-food within the environment and that a higher fat content in food facilitates rapid detection.