During the COVID-19 pandemic, wearing face masks is an important strategy to prevent people from infection, allowing people to find a balance between maintaining social interaction and keeping social distancing. Since face mask might disrupt information processing of social cognition, it could lead to less functional connectivity of occipital face area, fusiform face area, and superior temporal sulcus which interrupted the development of medial prefrontal cortex (MPFC) for mentalizing. However with better executive function (EF) people could process facial stimuli more efficiently. The objective of this study is to examine the effect of wearing face masks on preschoolers' facial emotion recognition, and the factors which might affect the development of facial emotion recognition.

In this study, preschoolers (N=44, 24 boys and 20 girls, aged 3 to 5 years-old) recruited from the community were asked to identify the emotions expressed in the 36 stimulus photos, each randomly presented with six emotion (happy, sad, angry, surprised, fearful, and disgusted). The total face stimulus photos were 2 (face sex) × 6 emotions × 3 facial features (full face, presenting upper counterparts of face with face mask covering the mouth, and presenting lower counterparts of face with hat covering the eyes). The EF of preschoolers and their parent were also evaluated to examine whether EF could predict the correct score of facial emotion recognition.

It was found that the correct score of emotion recognition increased with age. The recognition with full face feature were better than with upper feature and lower feature. When recognizing happy and disgust, participant tended to use lower features. When recognizing sad and angry, participant tended to use upper features. The EF of preschoolers could predict the correct score of emotion recognition. The EF of parents could predict the preschoolers' correct score of positive emotion recognition.

The ability of facial emotion recognition evolved rapidly in preschool age with the accumulation of social interaction experience and improved the development of auditory and visual subcortical cortex and the connectivity of MPFC. This study examined the emotion recognition ability of preschoolers and found that the face features preschoolers used to recognized emotion were consist with previous study. However, when the presenting stimulus were covered by face mask or hat, it was more difficult for preschoolers to recognizing emotion which would result in difficulty of understanding the social context and development of MPFC for mentalizing. In this study, it was found that preschooler's with better EF could be more efficiently recognizing facial emotion. Also, parents with better EF showed more positive emotion in daily life which lead to their children more sensitive to positive facial emotion.

Most emotion perception assessments were developed in western societies using English terms and Caucasian faces, so the extent to which they are cross-culturally valid is in question. To sort this, understanding the mechanisms of cultural variations is the key. In the past half-century, cross-cultural differences in perceiving facial emotions have been consistently reported and discussed, advancing knowledge to feed theoretical and practical interests. However, as these studies are heterogeneous in the questions asked and methods used, without understanding their association, we cannot provide a clear answer to the simple question: why do people from different cultures perceive facial emotions differently? This limitation represents a bottleneck for adapting western clinical assessments cross-culturally to suit the increasing trend of globalisation in research and testing. To address this issue, we conducted a systematic review aiming to reveal the effect of culture on emotion perception from past cross-cultural studies on healthy people. We expected this review to bridge findings in basic research and clinical application.

The systematic review followed the framework outlined in Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched five databases using three groups of keywords. We included all peer-reviewed original studies that 1) conducted cross-cultural comparison in facial emotion perception with healthy adults and 2) used a design that allowed identifying specific mechanisms to explain cultural variations.

The qualitative data synthesis included three steps: 1) categorising eligible studies according to the type of cross-cultural differences they investigated, 2) summarising the findings of each cluster, and 3) summarising the mechanisms revealed by the findings.

We found the 122 eligible articles clustered into five groups that investigated 1) how race and in-group and out-group status affected facial emotion perception; 2) cultural differences in using context to identify facial expressions; 3) cultural differences in emotion conceptualisation and how they affected facial emotion perception; 4) cultural differences in interpreting facial muscle configurations; 5) how culture interacted with the inference making process.

Seven mechanisms underlying cultural variations in facial emotion perception were revealed. These are facial emotion templates, emotion conceptualisation, in/out-group differentiation, information surveying strategies, belief that expressers are independent agents, reliance on the face and other emotion expressing channels, and stereotypes. The relative importance of these factors may depend on the cultures chosen to compare and the situational settings that affect how they work together in real life.

This review, for the first time, systematically addresses the mechanisms underlying cross-cultural differences in facial emotion perception. Besides advancing knowledge about this rapidly growing area, it guides what needs to be considered when designing new tests, adapting existing tests, and assessing the risk of bias brought about by cross-cultural issues.

To identify the patterns of errors in facial emotion recognition in frontotemporal dementia (FTD) subtypes compared with Alzheimer’s disease (AD) and healthy controls.

Retrospective analysis.

Participants were recruited from FRONTIER, the frontotemporal dementia research group at the University of Sydney, Australia.

A total of 356 participants (behavioral-variant FTD (bvFTD): 62, semantic dementia (SD)-left: 29, SD-right: 14, progressive non-fluent aphasia (PNFA): 21, AD: 76, controls: 90) were included.

Facial emotion recognition was assessed using the Facial Affect Selection Task, a word-face matching task measuring recognition of the six basic emotions (anger, disgust, fear, happiness, sadness, and surprise), as well as neutral emotion, portrayed by black and white faces.

Overall, all clinical groups performed significantly worse than controls with the exception of the PNFA subgroup (p = .051). The SD-right group scored worse than all other clinical groups (all p values < .027) and the bvFTD subgroup performed worse than the PNFA group (p < .001). The most frequent errors were in response to the facial emotions disgust (26.1%) and fear (22.9%). The primary error response to each target emotion was identified; patterns of errors were similar across all clinical groups.

Facial emotion recognition is impaired in FTD and AD compared to healthy controls. Within FTD, bvFTD and SD-right are particularly impaired. Dementia groups cannot be distinguished based on error responses alone. Implications for future clinical diagnosis and research are discussed.

Schizophrenia (SZ) and bipolar disorder (BD) may overlap in etiology and phenomenology but differ with regard to emotional processing. We used facial affect as a probe for emotional processing to determine whether there are diagnosis-related differences between SZ and BD in the function of the underlying neural circuitry.

Functional magnetic resonance imaging (fMRI) studies published up to 30 April 2012 investigating facial affect processing in patients with SZ or BD were identified through computerized and manual literature searches. Activation foci from 29 studies encompassing 483 healthy individuals, 268 patients with SZ and 267 patients with BD were subjected to voxel-based quantitative meta-analysis using activation likelihood estimation (ALE).

Compared to healthy individuals, when emotional facial stimuli were contrasted to neutral stimuli, patients with BD showed overactivation within the parahippocampus/amygdala and thalamus and reduced engagement within the ventrolateral prefrontal cortex (PFC) whereas patients with SZ showed underactivation throughout the entire facial affect processing network and increased activation in visual processing regions within the cuneus. Patients with BD showed greater thalamic engagement compared to patients with SZ; in the reverse comparison, patients with SZ showed greater engagement in posterior associative visual cortices.

During facial affect processing, patients with BD show overactivation in subcortical regions and underactivation in prefrontal regions of the facial affect processing network, consistent with the notion of reduced emotional regulation. By contrast, overactivation within visual processing regions coupled with reduced engagement of facial affect processing regions points to abnormal visual integration as the core underlying deficit in SZ.

Psychotic disorders are highly heritable such that the unaffected relatives of patients may manifest characteristics, or endophenotypes, that are more closely related to risk genes than the overt clinical condition. Facial affect processing is dependent on a distributed cortico-limbic network that is disrupted in psychosis. This study assessed facial affect processing and related brain structure as a candidate endophenotype of first-episode psychosis (FEP).

Three samples comprising 30 FEP patients, 30 of their first-degree relatives and 31 unrelated healthy controls underwent assessment of facial affect processing and structural magnetic resonance imaging (sMRI) data. Multivariate analysis (partial least squares, PLS) was used to identify a grey matter (GM) system in which anatomical variation was associated with variation in facial affect processing speed.

The groups did not differ in their accuracy of facial affect intensity rating but differed significantly in speed of response, with controls responding faster than relatives, who responded faster than patients. Within the control group, variation in speed of affect processing was significantly associated with variation of GM density in amygdala, lateral temporal cortex, frontal cortex and cerebellum. However, this association between cortico-limbic GM density and speed of facial affect processing was absent in patients and their relatives.

Speed of facial affect processing presents as a candidate endophenotype of FEP. The normal association between speed of facial affect processing and cortico-limbic GM variation was disrupted in FEP patients and their relatives.

Patients with bipolar disorder exhibit consistent deficits in facial affect identification at both behavioral and neural levels. However, little is known about which stages of facial affect processing are dysfunctional.

Event-related potentials (ERPs), including amplitude and latency, were used to evaluate two stages of facial affect processing: N170 to examine structural encoding of facial features and N250 to examine decoding of facial features in 57 bipolar disorder patients, 30 schizophrenia patients and 30 healthy controls. Three conditions were administered: participants were asked to identify the emotion of a face, the gender of a face, or whether a building was one or two stories tall.

Schizophrenia patients' emotion identification accuracy was lower than that of bipolar patients and healthy controls. N170 amplitude was significantly smaller in schizophrenia patients compared to bipolar patients and healthy controls, which did not differ from each other. Both patient groups had significantly longer N170 latency compared to healthy controls. For N250, both patient groups showed significantly smaller amplitudes compared with controls, but did not differ from each other. Bipolar patients showed longer N250 latency than healthy controls; patient groups did not differ from each other.

Bipolar disorder patients have relatively intact structural encoding of faces (N170) but are impaired when decoding facial features for complex judgments about faces (N250 latency and amplitude), such as identifying emotion or gender.

The Met allele of the catechol-O-methyltransferase (COMT) valine-to-methionine (Val158Met) polymorphism is known to affect dopamine-dependent affective regulation within amygdala–prefrontal cortical (PFC) networks. It is also thought to increase the risk of a number of disorders characterized by affective morbidity including bipolar disorder (BD), major depressive disorder (MDD) and anxiety disorders. The disease risk conferred is small, suggesting that this polymorphism represents a modifier locus. Therefore our aim was to investigate how the COMT Val158Met may contribute to phenotypic variation in clinical diagnosis using sad facial affect processing as a probe for its neural action.

We employed functional magnetic resonance imaging to measure activation in the amygdala, ventromedial PFC (vmPFC) and ventrolateral PFC (vlPFC) during sad facial affect processing in family members with BD (n=40), MDD and anxiety disorders (n=22) or no psychiatric diagnosis (n=25) and 50 healthy controls.

Irrespective of clinical phenotype, the Val158 allele was associated with greater amygdala activation and the Met158 allele with greater signal change in the vmPFC and vlPFC. Signal changes in the amygdala and vmPFC were not associated with disease expression. However, in the right vlPFC the Met158 allele was associated with greater activation in all family members with affective morbidity compared with relatives without a psychiatric diagnosis and healthy controls.

Our results suggest that the COMT Val158Met polymorphism has a pleiotropic effect within the neural networks subserving emotional processing. Furthermore the Met158 allele further reduces cortical efficiency in the vlPFC in individuals with affective morbidity.

Identification of emotional facial expression and emotional prosody (i.e. speech melody) is often impaired in schizophrenia. For facial emotion identification, a recent study suggested that the relative deficit in schizophrenia is enhanced when the presented emotion is easier to recognize. It is unclear whether this effect is specific to face processing or part of a more general emotion recognition deficit.

We used clarity-graded emotional prosodic stimuli without semantic content, and tested 25 in-patients with paranoid schizophrenia, 25 healthy control participants and 25 depressive in-patients on emotional prosody identification. Facial expression identification was used as a control task.

Patients with paranoid schizophrenia performed worse than both control groups in identifying emotional prosody, with no specific deficit in any individual emotion category. This deficit was present in high-clarity but not in low-clarity stimuli. Performance in facial control tasks was also impaired, with identification of emotional facial expression being a better predictor of emotional prosody identification than illness-related factors. Of those, negative symptoms emerged as the best predictor for emotional prosody identification.

This study suggests a general deficit in identifying high-clarity emotional cues. This finding is in line with the hypothesis that schizophrenia is characterized by high noise in internal representations and by increased fluctuations in cerebral networks.