Congenital prosopagnosia is associated with a genetic variation in the oxytocin receptor (OXTR) gene: An exploratory study

Functional characterization of OXTR-associated enhancers

The oxytocin receptor (OXTR) has a vital role in regulating human behavior, controlling lactation, parturition, pair bonding, maternal behavior, anxiety, and sociability. However, its regulatory elements and how variation in these sequences lead to behavioral changes remain largely unknown. Here, we identified seven OXTR candidate cis-regulatory elements (cCREs) from mouse and human hypothalamus single-cell RNA/ATAC-seq data and characterized them in cells and mice. Luciferase assays in hypothalamus cell lines identified three of the seven to be functional enhancers. Mouse enhancer assays for the most robust enhancer, OXTR candidate enhancer 7 (OCE7), found it to be active in the mouse olfactory bulb at postnatal day 28 and day 56. In summary, using genomic data coupled with cell and mouse enhancer assays, we characterized the OXTR regulatory landscape and identified a novel olfactory bulb OXTR-associated enhancer.

Disentangling developmental prosopagnosia: A scoping review of terms, tools and topics

The goal of this preregistered scoping review is to create an overview of the research on developmental prosopagnosia (DP). Through analysis of all empirical studies of DP in adults, we investigate 1) how DP is conceptualized and defined, 2) how individuals are classified with DP and 3) which aspects of DP are investigated in the literature. We reviewed 224 peer-reviewed studies of DP. Our analysis of the literature reveals that while DP is predominantly defined as a lifelong face recognition impairment in the absence of acquired brain injury and intellectual/cognitive problems, there is far from consensus on the specifics of the definition with some studies emphasizing e.g., deficits in face perception, discrimination and/or matching as core characteristics of DP. These differences in DP definitions is further reflected in the vast heterogeneity in classification procedures. Only about half of the included studies explicitly state how they classify individuals with DP, and these studies adopt 40 different assessment tools. The two most frequently studied aspects of DP are the role of holistic processing and the specificity of face processing, and alongside a substantial body of neuroimaging studies of DP, this paints a picture of a research field whose scientific interests and aims are rooted in cognitive neuropsychology and neuroscience. We argue that these roots - alongside the heterogeneity in DP definition and classification - may have limited the scope and interest of DP research unnecessarily, and we point to new avenues of research for the field.

Investigating the Influence of Autism Spectrum Traits on Face Processing Mechanisms in Developmental Prosopagnosia

Autism traits are common exclusionary criteria in developmental prosopagnosia (DP) studies. We investigated whether autism traits produce qualitatively different face processing in 43 DPs with high vs. low autism quotient (AQ) scores. Compared to controls (n = 27), face memory and perception were similarly deficient in the high- and low-AQ DPs, with the high-AQ DP group additionally showing deficient face emotion recognition. Task-based fMRI revealed reduced occipito-temporal face selectivity in both groups, with high-AQ DPs additionally demonstrating decreased posterior superior temporal sulcus selectivity. Resting-state fMRI showed similar reduced face-selective network connectivity in both DP groups compared with controls. Together, this demonstrates that high- and low-AQ DP groups have very similar face processing deficits, with additional facial emotion deficits in high-AQ DPs.

No increased prevalence of prosopagnosia in aphantasia: Visual recognition deficits are small and not restricted to faces

Aphantasia and prosopagnosia are both rare conditions with impairments in visual cognition. While prosopagnosia refers to a face recognition deficit, aphantasics exhibit a lack of mental imagery. Current object recognition theories propose an interplay of perception and mental representations, making an association between recognition performance and visual imagery plausible. While the literature assumes a link between aphantasia and prosopagnosia, other impairments in aphantasia have been shown to be rather global. Therefore, we assumed that aphantasics do not solely exhibit impairments in face recognition but rather in general visual recognition performance, probably moderated by stimulus complexity. To test this hypothesis, 65 aphantasics were compared to 55 controls in a face recognition task, the Cambridge Face Memory Test, and a corresponding object recognition task, the Cambridge Car Memory Test. In both tasks, aphantasics performed worse than controls, indicating mild recognition deficits without face-specificity. Additional correlations between imagery vividness and performance in both tasks were found, suggesting that visual imagery influences visual recognition not only in imagery extremes. Stimulus complexity produced the expected moderation effect but only for the whole imagery-spectrum and only with face stimuli. Overall, the results imply that aphantasia is linked to a general but mild deficit in visual recognition.

Prosopagnosia (face blindness) and child health during the COVID-19 pandemic

Prosopagnosia or 'face blindness' is the inability to recognise people's faces. There are two types: congenital or developmental prosopagnosia, which is the most common, and acquired prosopagnosia, which may occur secondary to brain tumours, stroke or other brain disorders. The authors of this article explored if mask wearing as a result of the restrictions imposed by the coronavirus disease 2019 (COVID-19) pandemic may affect social and developmental outcomes in children, including the development of prosopagnosia. Limited research on this topic is available and, although some relevant publications were found, no definitive evidence of mask-induced prosopagnosia in children was identified. However, nurses should be aware of this issue and discuss coping strategies to support children with the condition. Longitudinal studies on outcomes in children from different age groups who grew up during the COVID-19 pandemic will provide further insight.

Polygenic Risk Score Improves Cataract Prediction in East Asian Population

Cataracts, characterized by crystalline lens opacities in human eyes, is the leading cause of blindness globally. Due to its multifactorial complexity, the molecular mechanisms remain poorly understood. Larger cohorts of genome-wide association studies (GWAS) are needed to investigate cataracts’ genetic basis. In this study, a GWAS was performed on the largest Han population to date, analyzing a total of 7079 patients and 13,256 controls from the Taiwan Biobank (TWB) 2.0 cohort. Two cataract-associated SNPs with an adjustment of p < 1 × 10−7 in the older groups and nine SNPs with an adjustment of p < 1 × 10−6 in the younger group were identified. Except for the reported AGMO in animal models, most variations, including rs74774546 in GJA1 and rs237885 in OXTR, were not identified before this study. Furthermore, a polygenic risk score (PRS) was created for the young and old populations to identify high-risk cataract individuals, with areas under the receiver operating curve (AUROCs) of 0.829 and 0.785, respectively, after covariate adjustments. Younger individuals had 17.45 times the risk while older people had 10.97 times the risk when comparing individuals in the highest and lowest PRS quantiles. Validation analysis on an independent TWB1.0 cohort revealed AUROCs of 0.744 and 0.659.

The rehabilitation of object agnosia and prosopagnosia: A systematic review

BACKGROUND

Agnosia for objects is often overlooked in neuropsychology, especially with respect to rehabilitation. Prosopagnosia has been studied more extensively, yet there have been few attempts at training it. The lack of training protocols may partially be accounted for by their relatively low incidence and specificity to sensory modality. However, finding effective rehabilitations for such deficits may help to reduce their impact on the social and psychological functioning of individuals.

OBJECTIVE

Our aim in this study was to provide clinicians and researchers with useful information with which to conduct new studies on the rehabilitation of object agnosia and prosopagnosia. To accomplish this, we performed a systematic and comprehensive review of the effect of neuropsychological rehabilitation on visual object and prosopagnosia.

METHODS

The Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines were followed. In addition, the Single-Case Experimental Design (SCED) and the Critical Appraisal Skills Programme (CASP) scales were used to assess the quality of reporting.

RESULTS

Seven articles regarding object agnosia, eight articles describing treatments for prosopagnosia, and two articles describing treatments for both deficits were included.

CONCLUSIONS

In the light of the studies reviewed, treatments based on analysis of parts seem effective for object agnosia, while prosopagnosia appears to benefit most from treatments relying on holistic/configural processing. However, more attempts at rehabilitation of face and object agnosia are needed to clarify the mechanisms of these processes and possible rehabilitations. Moreover, a publication bias could mask a broader attempt to find effective treatments for visual agnosia and leaving out studies that are potentially more informative.

The enfacement illusion in autism spectrum disorder: How interpersonal multisensory stimulation influences facial recognition of the self

At its most basic level, the sense of self is built upon awareness of one's body and the face holds special significance as the individual's most important and distinctive physical feature. Multimodal sensory integration is pivotal to experiencing one's own body as a coherent visual "self" representation is formed and maintained by matching felt and observed sensorimotor experiences in the mirror. While difficulties in individual facial identity recognition and in both self-referential cognition and empathy are frequently reported in individuals with autism spectrum disorder (ASD), studying the effect of multimodal sensory stimulation in this population is of relevant interest. The present study investigates for the first time the specific effect on Interpersonal Multisensory Stimulation (IMS) on face self-recognition in a sample of 30 adults with (n = 15) and without (n = 15) ASD, matched on age and sex. The results demonstrate atypical self-face recognition and absence of IMS effects (enfacement illusion) in adults with ASD compared to controls, indicating that multisensory integration failed in updating cognitive representations of one's own face among persons with this disorder. The results are discussed in the light of other findings indicating alterations in body enfacement illusion and automatic imitation in ASD as well as in the context of the theories of procedural perception and multisensory integration alterations.

Accurate but inefficient: Standard face identity matching tests fail to identify prosopagnosia

In recent years, the number of face identity matching tests in circulation has grown considerably and these are being increasingly utilized to study individual differences in face cognition. Although many of these tests were designed for testing typical observers, recent studies have begun to utilize general-purpose tests for studying specific, atypical populations (e.g., super-recognizers and individuals with prosopagnosia). In this study, we examined the capacity of four tests requiring binary face-matching decisions to study individual differences between healthy observers. Uniquely, we used performance of the patient PS (Rossion, 2018), a well-documented case of acquired prosopagnosia (AP), as a benchmark. Two main findings emerged: (i) PS could exhibit typical rates of accuracy in all tests; (ii) compared to age-matched controls and when considering both accuracy and speed to account for potential trade-offs, only the KFMT - but not the EFCT, PICT or GFMT - was able to detect PS's severe impairment. These findings reflect the importance of considering both accuracy and response times to measure individual differences in face matching, and the need for comparing tests in terms of their sensitivity, when used as a measure of human cognition and brain functioning.

Prosopagnosia and disorders of face processing

Face recognition is a form of expert visual processing. Acquired prosopagnosia is the loss of familiarity for facial identity and has several functional variants, namely apperceptive, amnestic, and associative forms. Acquired forms are usually caused by either occipitotemporal or anterior temporal lesions, right or bilateral in most cases. In addition, there is a developmental form, whose functional and structural origins are still being elucidated. Despite their difficulties with recognizing faces, some of these subjects still show signs of covert recognition, which may have a number of explanations. Other aspects of face perception can be spared in prosopagnosic subjects. Patients with other types of face processing difficulties have been described, including impaired expression processing, impaired lip-reading, false familiarity for faces, and a people-specific amnesia. Recent rehabilitative studies have shown some modest ability to improve face perception in prosopagnosic subjects through perceptual training protocols.

Face individual identity recognition: a potential endophenotype in autism

BACKGROUND

Face individual identity recognition skill is heritable and independent of intellectual ability. Difficulties in face individual identity recognition are present in autistic individuals and their family members and are possibly linked to oxytocin polymorphisms in families with an autistic child. While it is reported that developmental prosopagnosia (i.e., impaired face identity recognition) occurs in 2-3% of the general population, no prosopagnosia prevalence estimate is available for autism. Furthermore, an autism within-group approach has not been reported towards characterizing impaired face memory and to investigate its possible links to social and communication difficulties.

METHODS

The present study estimated the prevalence of prosopagnosia in 80 autistic adults with no intellectual disability, investigated its cognitive characteristics and links to autism symptoms' severity, personality traits, and mental state understanding from the eye region by using standardized tests and questionnaires.

RESULTS

More than one third of autistic participants showed prosopagnosia. Their face memory skill was not associated with their symptom's severity, empathy, alexithymia, or general intelligence. Face identity recognition was instead linked to mental state recognition from the eye region only in autistic individuals who had prosopagnosia, and this relationship did not depend on participants' basic face perception skills. Importantly, we found that autistic participants were not aware of their face memory skills.

LIMITATIONS

We did not test an epidemiological sample, and additional work is necessary to establish whether these results generalize to the entire autism spectrum.

CONCLUSIONS

Impaired face individual identity recognition meets the criteria to be a potential endophenotype in autism. In the future, testing for face memory could be used to stratify autistic individuals into genetically meaningful subgroups and be translatable to autism animal models.

Developmental Prosopagnosia and Elastic Versus Static Face Recognition in an Incidental Learning Task

Previous research on the beneficial effect of motion has postulated that learning a face in motion provides additional cues to recognition. Surprisingly, however, few studies have examined the beneficial effect of motion in an incidental learning task and developmental prosopagnosia (DP) even though such studies could provide more valuable information about everyday face recognition compared to the perception of static faces. In the current study, 18 young adults (Experiment 1) and five DPs and 10 age-matched controls (Experiment 2) participated in an incidental learning task during which both static and elastically moving unfamiliar faces were sequentially presented and were to be recognized in a delayed visual search task during which the faces could either keep their original presentation or switch (from static to elastically moving or vice versa). In Experiment 1, performance in the elastic-elastic condition reached a significant improvement relative to the elastic-static and static-elastic condition, however, no significant difference could be detected relative to the static-static condition. Except for higher scores in the elastic-elastic compared to the static-elastic condition in the age-matched group, no other significant differences were detected between conditions for both the DPs and the age-matched controls. The current study could not provide compelling evidence for a general beneficial effect of motion. Age-matched controls performed generally worse than DPs, which may potentially be explained by their higher rates of false alarms. Factors that could have influenced the results are discussed.

The effect of intranasal oxytocin on visual processing and salience of human faces

The mechanisms underlying the role of oxytocin (OT) as a regulator of social behavior in mammals are only partly understood. Recently, it has been proposed that OT increases the salience of social stimuli. We carried out a randomized, double-blind, cross-over study of the effects of OT on binocular rivalry, a visual phenomenon underpinned by the interplay of excitation and inhibition in the cortex. A final sample of 45 participants viewed images of social stimuli (faces with different emotional expressions) and non-social stimuli (houses and Gabor patches). We demonstrate a robust effect that intranasal OT increases the salience of human faces in binocular rivalry, such that dominance durations of faces are longer-this effect is not modulated by the facial expression. We tentatively show that OT treatment increases dominance durations for non-social stimuli. Our results lend support to the social salience hypothesis of OT, and in addition offer provisional support for the role of OT in influencing excitation-inhibition balance in the brain.

Diagnosing developmental prosopagnosia: repeat assessment using the Cambridge Face Memory Test

Developmental prosopagnosia (DP) is a cognitive condition characterized by a relatively selective impairment in face recognition. Currently, people are screened for DP via a single attempt at objective face-processing tests, usually all presented on the same day. However, several variables probably influence performance on these tests irrespective of actual ability, and the influence of repeat administration is also unknown. Here, we assess, for the first known time, the test-retest reliability of the Cambridge Face Memory Test (CFMT)-the leading task used worldwide to diagnose DP. This value was found to fall just below psychometric standards, and single-case analyses revealed further inconsistencies in performance that were not driven by testing location (online or in-person), nor the time-lapse between attempts. Later administration of an alternative version of the CFMT (the CFMT-Aus) was also found to be valuable in confirming borderline cases. Finally, we found that performance on the first 48 trials of the CFMT was equally as sensitive as the full 72-item score, suggesting that the instrument may be shortened for testing efficiency. We consider the implications of these findings for existing diagnostic protocols, concluding that two independent tasks of unfamiliar face memory should be completed on separate days.

COMT-Polymorphisms Modulated Functional Profile of the Fusiform Face Area Contributes to Face-Specific Recognition Ability

Previous studies have shown that face-specific recognition ability (FRA) is heritable; however, the neural basis of this heritability is unclear. Candidate gene studies have suggested that the catechol-O-methyltransferase (COMT) rs4680 polymorphism is related to face perception. Here, using a partial least squares (PLS) method, we examined the multivariate association between 12 genotypes of 4 COMT polymorphisms (rs6269-rs4633-rs4818-rs4680) and multimodal MRI phenotypes in the human fusiform face area (FFA), which selectively responds to face stimuli, in 338 Han Chinese adults (mean age 20.45 years; 135 males). The MRI phenotypes included gray matter volume (GMV), resting-state fractional amplitude of low-frequency fluctuations (fALFF), and face-selective blood-oxygen-level-dependent (BOLD) responses (FS). We found that the first COMT-variant component (PLS1) was positively associated with the FS but negatively associated with the fALFF in the FFA. Moreover, participants with the COMT heterozygous-HEA-haplotype showed higher PLS1 FFA-MRI scores, which were positively associated with the FRA in an old/new face recognition task, than those with the COMT homozygous HEA haplotype and HEA non-carriers, suggesting that individuals with an appropriate (intermediate) level of dopamine activity in the FFA might have better FRA. In summary, our study provides empirical evidence for the genetic and neural basis for the heritability of face recognition and informs the formation of neural module functional specificity.

Progress in perceptual research: the case of prosopagnosia

Prosopagnosia is an impairment in the ability to recognize faces and can be acquired after a brain lesion or occur as a developmental variant. Studies of prosopagnosia make important contributions to our understanding of face processing and object recognition in the human visual system. We review four areas of advances in the study of this condition in recent years. First are issues surrounding the diagnosis of prosopagnosia, including the development and evaluation of newer tests and proposals for diagnostic criteria, especially for the developmental variant. Second are studies of the structural basis of prosopagnosia, including the application of more advanced neuroimaging techniques in studies of the developmental variant. Third are issues concerning the face specificity of the defect in prosopagnosia, namely whether other object processing is affected to some degree and in particular the status of visual word processing in light of recent predictions from the "many-to-many hypothesis". Finally, there have been recent rehabilitative trials of perceptual learning applied to larger groups of prosopagnosic subjects that show that face impairments are not immutable in this condition.

Self-face and self-body advantages in congenital prosopagnosia: evidence for a common mechanism

Prosopagnosia is a disorder leading to difficulties in recognizing faces. However, recent evidence suggests that individuals with congenital prosopagnosia can achieve considerable accuracy when they have to recognize their own faces (self-face advantage). Yet, whether this advantage is face-specific or not is still unclear. Here, we aimed to investigate whether individuals with congenial prosopagnosia show a self-advantage also in recognizing other self body-parts and, if so, whether the advantage for the body parts differs from the one characterizing the self-face. Eight individuals with congenital prosopagnosia and 22 controls underwent a delayed matching task in which they were required to recognize faces, hands and feet belonging to the self or to others. Controls showed a similar self-advantage for all the stimuli tested; by contrast, individuals with congenital prosopagnosia showed a larger self-advantage with faces compared to hands and feet, mainly driven by their deficit with others' faces. In both groups the self-advantages for the different body parts were strongly and significantly correlated. Our data suggest that the self-face advantage showed by individuals with congenital prosopagnosia is not face-specific and that the same mechanism could be responsible for both the self-face and self body-part advantages.

Tests of whole upright face processing in prosopagnosia: A literature review

Prosopagnosia refers to an acquired or developmental deficit in face recognition. This neuropsychological impairment has received increasing attention over the last decade, in particular because of an increased scientific interest in developmental prosopagnosia. Studies investigating prosopagnosia have used a variety of different clinical and experimental tests to assess face processing abilities. With such a large variety of assessment methods available, test selection can be challenging. Some previous works have aimed to provide an overview of tests used to diagnose prosopagnosia. However, no overview that is based on a structured review of the literature is available. We review the literature to identify tests that have been used to assess the processing of whole upright faces in acquired and developmental prosopagnosia over the last five years (2013-2017). We not only review tests that have been used for diagnostic purposes, but also tests that have been used for experimental purposes. Tests are categorised according to i) their experimental designs and, ii) the stage of face processing that they assess. On this basis, we discuss considerations regarding test designs for future studies. A visual illustration providing a structured overview of paradigms available for testing the processing of whole upright faces is provided. This visual illustration can be used to inform test selection when designing a study and to apply a structured approach to interpreting findings from the literature. The different approaches to assessment of face processing in prosopagnosia have been necessary and fruitful in generating data and hypotheses about the cause of face processing deficits. However, impairments at different levels of face processing have often been interpreted as reflecting a deficit in the recognition stage of face processing. Based on the data now available on prosopagnosia, we advocate for a more structured approach to assessment, which may facilitate a better understanding of the key deficits in prosopagnosia and of the level(s) of face processing that are impaired.

Neurobiological Aspects of Face Recognition: The Role of Oxytocin

Face recognition is an important index in the formation of social cognition and neurodevelopment in humans. Changes in face perception and memory are connected with altered sociability, which is a symptom of numerous brain conditions including autism spectrum disorder (ASD). Various brain regions and neuropeptides are implicated in face processing. The neuropeptide oxytocin (OT) plays an important role in various social behaviors, including face and emotion recognition. Nasal OT administration is a promising new therapy that can address social cognition deficits in individuals with ASD. New instrumental neurotechnologies enable the assessment of brain region activation during specific social tasks and therapies, and can characterize the involvement of genes and peptides in impaired neurodevelopment. The present review sought to discuss some of the mechanisms of the face distinguishing process, the ability of OT to modulate social cognition, as well as new perspectives and technologies for research and rehabilitation of face recognition.

TMS over right OFA affects individuation of faces but not of exemplars of objects

In addition to its well-documented role in processing of faces, the occipital face area in the right hemisphere (rOFA) may also play a role in identifying specific individuals within a class of objects. Here we explored this issue by using fMRI-guided TMS. In a first experiment, participants had to judge whether two sequentially presented images of faces or objects represented exactly the same exemplar or two different exemplars of the same class, while receiving online TMS over either the rOFA, the right lateral occipital cortex (rLO) or the Vertex (control). We found that, relative to Vertex, stimulation of rOFA impaired individuation of faces only, with no effect on objects; in contrast, TMS over rLO reduced individuation of objects but not of faces. In a second control experiment participants judged whether a picture representing a fragment of a stimulus belonged or not to the subsequently presented image of a whole stimulus (part-whole matching task). Our results showed that rOFA stimulation selectively disrupted performance with faces, whereas performance with objects (but not with faces) was selectively affected by TMS over rLO. Overall, our findings suggest that rOFA does not contribute to discriminate between exemplars of non-face objects.

Identifying Hallmark Symptoms of Developmental Prosopagnosia for Non-Experts

Developmental prosopagnosia (DP) is characterised by a severe and relatively selective deficit in face recognition, in the absence of neurological injury. Because public and professional awareness of DP is low, many adults and children are not identified for formal testing. This may partly result from the lack of appropriate screening tools that can be used by non-experts in either professional or personal settings. To address this issue, the current study sought to (a) explore when DP can first be detected in oneself and another, and (b) identify a list of the condition’s everyday behavioural manifestations. Questionnaires and interviews were administered to large samples of adult DPs, their unaffected significant others, and parents of children with the condition; and data were analysed using inductive content analysis. It was found that DPs have limited insight into their difficulties, with most only achieving realisation in adulthood. Nevertheless, the DPs’ reflections on their childhood experiences, together with the parental responses, revealed specific indicators that can potentially be used to spot the condition in early childhood. These everyday hallmark symptoms may aid the detection of individuals who would benefit from objective testing, in oneself (in adults) or another person (for both adults and children).