The influence of dynamism and expression intensity on face emotion recognition in individuals with autistic traits.

Face emotion recognition (FER) ability varies across the population, with autistic traits in the general population reported to contribute to this variation. Previous studies used photographs of posed facial expressions, while real social encounters involve dynamic expressions of varying intensity. We used static photographs and dynamic videos, showing peak and partial facial expressions to investigate the influence of dynamism and expression intensity on FER in non-clinical adults who varied in autistic traits. Those with high autistic traits had lower accuracy with both static peak and dynamic partial intensity expressions, when compared to low autistic trait participants. Furthermore, high autistic traits were linked to an accuracy advantage for dynamic compared with static stimuli in both partial and peak expression conditions, while those with low autistic traits demonstrated this dynamic advantage only for partial expressions. These findings reveal the differing importance of dynamism and expression intensity for FER across the non-clinical population and appear linked to self-reported social-communication skills. Furthermore, FER difficulties in autism might relate to the ability to integrate subtle, dynamic information, rather than static emotion categorisation alone.

Can deepfakes be used to study emotion perception? A comparison of dynamic face stimuli.

Video recordings accurately capture facial expression movements; however, they are difficult for face perception researchers to standardise and manipulate. For this reason, dynamic morphs of photographs are often used, despite their lack of naturalistic facial motion. This study aimed to investigate how humans perceive emotions from faces using real videos and two different approaches to artificially generating dynamic expressions - dynamic morphs, and AI-synthesised deepfakes. Our participants perceived dynamic morphed expressions as less intense when compared with videos (all emotions) and deepfakes (fearful, happy, sad). Videos and deepfakes were perceived similarly. Additionally, they perceived morphed happiness and sadness, but not morphed anger or fear, as less genuine than other formats. Our findings support previous research indicating that social responses to morphed emotions are not representative of those to video recordings. The findings also suggest that deepfakes may offer a more suitable standardized stimulus type compared to morphs. Additionally, qualitative data were collected from participants and analysed using ChatGPT, a large language model. ChatGPT successfully identified themes in the data consistent with those identified by an independent human researcher. According to this analysis, our participants perceived dynamic morphs as less natural compared with videos and deepfakes. That participants perceived deepfakes and videos similarly suggests that deepfakes effectively replicate natural facial movements, making them a promising alternative for face perception research. The study contributes to the growing body of research exploring the usefulness of generative artificial intelligence for advancing the study of human perception.

Embracing deepfakes and AI-generated images in neuroscience research.

The rise of deepfakes and AI-generated images has raised concerns regarding their potential misuse. However, this commentary highlights the valuable opportunities these technologies offer for neuroscience research. Deepfakes deliver accessible, realistic and customisable dynamic face stimuli, while generative adversarial networks (GANs) can generate and modify diverse and high-quality static content. These advancements can enhance the variability and ecological validity of research methods and enable the creation of previously unattainable stimuli. When AI-generated images are informed by brain responses, they provide unique insights into the structure and function of visual systems. The authors argue that experimental psychologists and cognitive neuroscientists stay informed about these emerging tools and embrace their potential to advance the field of visual neuroscience.

Perceptual size discrimination requires awareness and late visual areas: A continuous flash suppression and interocular transfer study.

We applied continuous flash suppression (CFS) during an interocular transfer paradigm to evaluate the importance of awareness and the contribution of early versus late visual structures in size recognition. Specifically, we tested if size judgements of a visible target could be influenced by a congruent or incongruent prime presented to the same or different eye. Without CFS, participants categorised a target as "small" or "large" more quickly when it was preceded by a congruent prime - regardless of whether the prime and target were presented to the same or different eye. Interocular transfer enabled us to infer that the observed priming was mediated by late visual areas. In contrast, there was no priming under CFS, which underscores the importance of awareness. We conclude that awareness and late visual structures are important for size perception and that any subconscious processing of the stimulus has minimal effect on size recognition.

Conscious awareness is required for the perceptual discrimination of threatening animal stimuli: A visual masking and continuous flash suppression study.

We investigated if the subliminal processing of threatening animal (snakes and spiders) and neutral object (cars and houses) stimuli can influence the discrimination of a subsequent visible stimulus. The prime and target pair were either identical, of the same category but with different physical features, or different in category and physical features. In two experiments, participants discriminated the basic level category (e.g. snake vs. spider) of a visible target stimulus that had been preceded by a visible or perceptually invisible prime stimulus. One experiment used visual masking to render prime stimuli perceptually invisible and the other used continuous flash suppression (CFS). Priming effects were demonstrated in both experiments when the prime was visible but not when the prime was rendered perceptually invisible. These findings demonstrate that conscious awareness could be required in the perceptual discrimination of threatening animal and neutral object images at their specific basic level category.

Autism Traits and Cognitive Performance: Mediating Roles of Sleep Disturbance, Anxiety and Depression.

Theories about autism spectrum disorder (ASD) have addressed cognitive deficits however few have examined how comorbid diagnoses, including sleep disturbance, anxiety and depression contribute to the underlying deficits. We investigated potential mediations of common ASD comorbidities in the relationship between sub-clinical autism traits and cognitive performance using an international community sample. Cognitive tasks assessed working memory [executive functioning (EF) theory], mental state attribution [theory of mind (ToM)], and global/local visual processing [weak central coherence (WCC) theory]. Structural equation modelling (SEM) demonstrated sleep disturbance and anxiety mediated the relationship of autism traits on measures of EF, but not WCC and ToM. This suggests that treating the symptoms of sleep disturbance and anxiety may lead to improvements in working memory.

Faster social attention disengagement in individuals with higher autism traits.

INTRODUCTION: Atypical visual and social attention has often been associated with clinically diagnosed autism spectrum disorder (ASD), and with the broader autism phenotype. Atypical social attention is of particular research interest given the importance of facial expressions for social communication, with faces tending to attract and hold attention in neurotypical individuals. In autism, this is not necessarily so, where there is debate about the temporal differences in the ability to disengage attention from a face. METHOD: Thus, we have used eye-tracking to record saccadic latencies as a measure of time to disengage attention from a central task-irrelevant face before orienting to a newly presented peripheral nonsocial target during a gap-overlap task. Neurotypical participants with higher or lower autism-like traits (AT) completed the task that included central stimuli with varied expressions of facial emotion as well as an inverted face. RESULTS: High AT participants demonstrated faster saccadic responses to detect the nonsocial target than low AT participants when disengaging attention from a face. Furthermore, faster saccadic responses were recorded when comparing disengagement from upright to inverted faces in low AT but not in high AT participants. CONCLUSIONS: Together, these results extend findings of atypical social attention disengagement in autism and highlight how differences in attention to faces in the broader autism phenotype can lead to apparently superior task performance under certain conditions. Specifically, autism traits were linked to faster attention orienting to a nonsocial target due to the reduced attentional hold of the task irrelevant face stimuli. The absence of an inversion effect in high AT participants also reinforces the suggestion that they process upright or inverted faces similarly, unlike low AT participants for whom inverted faces are thought to be less socially engaging, thus allowing faster disengagement.

Dorsal stream involvement in recognition of objects with transient onset but not with ramped onset.

BACKGROUND: Although the ventral visual stream is understood to be responsible for object recognition, it has been proposed that the dorsal stream may contribute to object recognition by rapidly activating parietal attention mechanisms, prior to ventral stream object processing. METHODS: To investigate the relative contribution of the dorsal visual stream to object recognition a group of tertiary students were divided into good and poor motion coherence groups and assessed on tasks classically assumed to rely on ventral stream processing. Participants were required to identify simple line drawings in two tasks, one where objects were presented abruptly for 50 ms followed by a white-noise mask, the other where contrast was linearly ramped on and off over 325 ms and replaced with a mask. RESULTS: Although both groups only differed in motion coherence performance (a dorsal stream measure), the good motion coherence group showed superior contrast sensitivity for object recognition on the abrupt, but not the ramped presentation tasks. CONCLUSIONS: We propose that abrupt presentation of objects activated attention mechanisms fed by the dorsal stream, whereas the ramped presentation had reduced transience and thus did not activate dorsal attention mechanisms as well. The results suggest that rapid dorsal stream activation may be required to assist with ventral stream object processing.

Alterations in Rapid Social Evaluations in Individuals with High Autism Traits.

Typically developing adults with low and high Autism Spectrum Quotient (AQ) scores made rapid social evaluations of neutral faces when these were primed by briefly presented emotional faces. High AQ participants rated neutral faces as more threatening than low AQ participants, regardless of the prime condition. Both groups rated target neutral faces as more threatening with fearful compared with neutral primes, while neither group demonstrated an effect of happy primes on the ratings of neutral target faces. These results demonstrate subtle anomalies in rapid visual processing of emotional faces across the broader autism spectrum. They suggest that higher autism traits may be associated with a generalized threat bias in rapid social evaluations.

Corrigendum: Saccade Latency Provides Evidence for Reduced Face Inversion Effects With Higher Autism Traits.

[This corrects the article DOI: 10.3389/fnhum.2019.00470.].

TMS disruption of V5/MT+ indicates a role for the dorsal stream in word recognition.

Although word recognition is a skill commonly expected to rely more on ventral rather than dorsal stream processing, there is some evidence for a magnocellular/dorsal impairment in dyslexia. The early rapid feedforward/feedback loop through the dorsal stream seen in primate has been suggested to allow an initial global analysis, and in human early activation of parietal attention mechanisms for detecting salient stimuli, facilitating more local level detailed ventral stream processing. To test this model in humans, transcranial magnetic stimulation (TMS) was used to probe the role of early visual cortex (V1/V2) and V5/MT+ in single word identification. TMS over V1/V2 between word onset and 36 ms post word onset disrupted accurate word discrimination, with disruption also evident at approximately 99 ms. TMS over V5/MT+ also disrupted accuracy following stimulation at approximately the same time as word onset and again at 130 ms post word onset. Thus, a role for V5/MT+ in accurate single word identification is apparent suggesting rapid triggering of attention to salient exogenous stimuli may be required prior to processing in primary and temporal cortical regions.

Subclinical high schizotypy traits are associated with slower change detection.

Patients with schizophrenia often show impairments in visual information processing that have been linked to abnormal magnocellular or dorsal stream functioning. However, such deficits are not consistently reported, possibly due to the broad symptomology inherent to schizophrenia, and/or medication effects. To avoid these latter issues this study employed visual perceptual tasks targeting magnocellular (flicker-defined form contrast threshold), dorsal stream (motion coherence, change detection) and ventral stream (form coherence) processing, and compared performance of groups of high and low sub-clinical schizotypy traits from a neurotypical population (n = 20 per group). Significantly worse performance of high compared with low schizotypy participants was only demonstrated on the change detection task that requires rapid attention acquisition and encoding of the first visual array into short term memory prior to a comparison of a second array presentation. No group differences on the other tasks were established. Given this potentially important effect is apparent in a non-clinical population, there are likely to be implications for understanding visual and attentional abnormalities in the schizophrenia spectrum more broadly.

Anxiety as a Common Biomarker for School Children With Additional Health and Developmental Needs Irrespective of Diagnosis.

Currently very little evidence is available regarding the biological characteristics and common comorbid behaviors that are associated with children characterized by learning difficulties who require additional support at school. These children are usually referred to as having Additional Health and Developmental Needs by the Australian Government and the associated public education system more broadly though the problems may arise from academic, social and/or emotional stressors and may or may not include children with clinically diagnosed Neurodevelopmental Disorders. Thus, the aim of this study was to investigate the relationship between anxiety levels (Spence Children's Anxiety Scale- Parent Report), autism traits (Autism Spectrum Quotient - Child Version) and sleep quality (Sleep Disturbance Scale for Children) in children with Additional Health and Developmental Needs without an intellectual disability, but with either a diagnosis of Autism Spectrum Disorder (ASD) (N = 25), Speech and Language Impairment (N = 37) or Other Diagnosis (N = 22). Our results demonstrated that these children with Additional Health and Developmental Needs showed atypically high levels of anxiety and impaired sleep quality, with the ASD group reporting more impairments associated with comorbid anxiety and sleep quality than either of the other clinically diagnosed groups. In fact, greater anxiety level was associated with a greater number of autism traits and poorer sleep quality regardless of diagnostic group suggesting that anxiety is a common experience for children with Additional Health and Developmental Needs. It is suggested that assessment of anxiety, sleep behaviors and autism traits may be useful markers for early identification of children within this population, thus providing scope for early and targeted intervention.

Saccade Latency Provides Evidence for Reduced Face Inversion Effects With Higher Autism Traits.

Individuals on the autism spectrum are reported to show impairments in the processing of social information, including aspects of eye-movements towards faces. Abnormalities in basic-level visual processing are also reported. In the current study, we sought to determine if the latency of saccades made towards social targets (faces) in a natural scene as opposed to inanimate targets (cars) would be related to sub-clinical autism traits (ATs) in individuals drawn from a neurotypical population. The effect of stimulus inversion was also examined given that difficulties with processing inverted faces are thought to be a function of face expertise. No group differences in saccadic latency were established for face or car targets, regardless of image orientation. However, as expected, we found that individuals with higher autism-like traits did not demonstrate a saccadic face inversion effect, but those with lower autism-like traits did. Neither group showed a car inversion effect. Thus, these results suggest that neurotypical individuals with high autism-like traits also show anomalies in detecting and orienting to faces. In particular, the reduced saccadic face inversion effect established in these participants with high ATs suggests that speed of visual processing and orienting towards faces may be associated with the social difficulties found across the broader autism spectrum.

Towards an understanding of the role of the 'magnocellular advantage' in fluent reading.

Reading disability is a relatively common developmental disorder, the aetiology of which is clouded by conflicting theoretical approaches and the heterogeneity of the subtypes found. Recent advances in understanding of the visual system have revived interest in the role of visual processing in the persisting inability to read fluently that characterises dyslexia. A new integrated model of visual processing based on primate single cell and human electrophysiology may provide such a framework, implicating the magnocellular pathway's role in activating and driving attentional mechanisms in higher order cortical regions. In particular, the recent introduction of transcranial magnetic stimulation (TMS) to create 'transient lesions' may provide causal evidence for dorsal stream feedforward/feedback involvement in rapid visual processing tasks. Such organization is argued to be crucial for the development of fluent reading.

A transcranial magnetic stimulation study of transcallosal inhibition and facilitation in schizophrenia.

Deficits in cortical inhibition (CI) have been implicated in the pathophysiology of schizophrenia, including decreased transcallosal inhibition (TCI). A closely related phenomenon, which has not yet been studied in schizophrenia, is transcallosal facilitation (TCF). TCI and TCF are thought to maintain a complimentary existence, allowing for the performance of tasks such as unilateral voluntary movement. Therefore, deficient TCI may lead to abnormal expression of TCF. This study aims to confirm the presence of TCI deficits in schizophrenia, and to examine TCF. Thirty consenting participants took part in the study (15 with schizophrenia and 15 healthy controls), although not all were able to complete all aspects of the study. TCI and TCF were measured using dual-pulse transcranial magnetic stimulation methodologies. Patients with schizophrenia exhibited significantly less TCI than controls; there was no difference in TCF, however. The lack of significant TCF findings is discussed in light of the methodological limitations, while the theoretical significance of deficient TCI to the pathophysiology of schizophrenia is considered.

Perceptual Discrimination of Basic Object Features Is Not Facilitated When Priming Stimuli Are Prevented From Reaching Awareness by Means of Visual Masking.

Our understanding of how form, orientation and size are processed within and outside of awareness is limited and requires further investigation. Therefore, we investigated whether or not the visual discrimination of basic object features can be influenced by subliminal processing of stimuli presented beforehand. Visual masking was used to render stimuli perceptually invisible. Three experiments examined if visible and invisible primes could facilitate the subsequent feature discrimination of visible targets. The experiments differed in the kind of perceptual discrimination that participants had to make. Namely, participants were asked to discriminate visual stimuli on the basis of their form, orientation, or size. In all three experiments, we demonstrated reliable priming effects when the primes were visible but not when the primes were made invisible. Our findings underscore the importance of conscious awareness in facilitating the perceptual discrimination of basic object features.

A comparative study of the effects of repetitive paired transcranial magnetic stimulation on motor cortical excitability.

OBJECTIVES: Various methods of application of repetitive transcranial magnetic stimulation (TMS) have been evaluated for their potential capacity to alter motor cortical excitability. Initial research suggests that the repetitive application of paired TMS pulses (repetitive paired pulse TMS (rppTMS)) may have greater effects on cortical excitability, perhaps through the facilitation of I-wave interaction. We aimed to compare the post-train effects of 15 min trains of rppTMS to investigate the potential therapeutic application of this technique as well as to compare it to a standard high frequency repetitive TMS paradigm. METHODS: Ten normal subjects received three 15 min sessions of rppTMS, 5 Hz high frequency rTMS and sham TMS in randomised order. rppTMS consisted of a single train of 180 pulse pairs (0.2 Hz, 1.5 ms inter-stimulus interval, supra-threshold intensity) administered over 15 min. The rTMS condition involved 750 pulses provided in 5s 5 Hz trains with a 25s inter-train interval at 90% of the RMT. Motor evoked potential size and cortical silent period duration were assessed before and after each session. RESULTS: There were no significant changes in cortical excitability produced by any of the stimulation conditions. Five hertz rTMS produced an increase in cortical silent period duration (p=0.004) which was not affected by rppTMS. CONCLUSIONS: Fifteen minutes trains of 1.5ms rppTMS do not substantially increase post train cortical excitability. Repetitive brief trains of 5Hz rTMS also do not alter excitability but appear to effect cortical inhibition.

Attention Orienting in Response to Non-conscious Hierarchical Arrows: Individuals with Higher Autistic Traits Differ in Their Global/Local Bias.

One aspect of the social communication impairments that characterize autism spectrum disorder (ASD) include reduced use of often subtle non-verbal social cues. People with ASD, and those with self-reported sub-threshold autistic traits, also show impairments in rapid visual processing of stimuli unrelated to social or emotional properties. Hence, this study sought to investigate whether perceptually non-conscious visual processing is related to autistic traits. A neurotypical sample of thirty young adults completed the Subthreshold Autism Trait Questionnaire and a Posner-like attention cueing task. Continuous Flash Suppression (CFS) was employed to render incongruous hierarchical arrow cues perceptually invisible prior to consciously presented targets. This was achieved via a 10 Hz masking stimulus presented to the dominant eye that suppressed information presented to the non-dominant eye. Non-conscious arrows consisted of local arrow elements pointing in one direction, and forming a global arrow shape pointing in the opposite direction. On each trial, the cue provided either a valid or invalid cue for the spatial location of the subsequent target, depending on which level (global or local) received privileged attention. A significant autism-trait group by global cue validity interaction indicated a difference in the extent of non-conscious local/global cueing between groups. Simple effect analyses revealed that whilst participants with lower autistic traits showed a global arrow cueing effect, those with higher autistic traits demonstrated a small local arrow cueing effect. These results suggest that non-conscious processing biases in local/global attention may be related to individual differences in autistic traits.