Pupillometry reveals reduced unconscious emotional reactivity in autism

Impairment of affective and cognitive empathy in high functioning autism is mediated by alterations in emotional reactivity

Empathy impairments are considered a key aspect of autism-spectrum disorders (ASD). Previous research consistently shows reduced cognitive empathy, but findings on affective empathy vary, possibly due to experimental design variations (e.g., stimulus modality, social distance) and individual psychological factors (e.g., perceptual abilities, emotional reactivity). This study aims to clarify deficits in affective and cognitive empathy in ASD by addressing these contributing factors. Empathy was examined in 34 autistic individuals and 33 typically developed controls (TDCs) through the Textual Empathy Test (TET). The TET was developed to assess emotional responses when imagining oneself (emotional reactivity) as compared to a target person (friend, stranger) in emotional situations presented via short verbal descriptions. Participants rated emotional states of the target person (cognitive empathy) as well as their own emotional responses when imagining the target person in that situation (affective empathy). Ratings were interpreted relative to normative mean values through standardized regression coefficients. Results showed that high-functioning autism was associated with lower cognitive and affective empathy irrespective of social distance as well as with decreased emotional reactivity compared to controls. Moreover, emotional reactivity mediated the impact of ASD on both empathic components. In summary, altered emotional reactivity may underlie impaired empathy in autistic individuals.

Temporal progression of pupil dilation and gaze behavior to emotion expressions in preschoolers with autism spectrum disorder

Previous work has shown divergent pupil dilation (PD) and gaze behavior in individuals with autism spectrum disorder (ASD), which may relate to the development of social difficulties in early life. Here, we investigated temporal dynamics of both phenotypes during naturalistic videos of a person displaying facial emotion expressions in 61 autistic and 61 non-autistic preschoolers. PD was segmented into three serial time components derived from a principal component analysis. Growth curve analysis was applied to analyze changes in looking time on eye and mouth regions over time. Groups did not differ in PD time components. Growth curve analysis revealed initially shorter looking times on the eyes and longer looking times on the mouth in autistic versus non-autistic preschoolers. However, a reversion of this pattern was observed over time, suggesting a delayed compensatory increase in eye attention during prolonged viewing periods in autistic children. Positive and negative associations of PD components and gaze behavior over time indicated a dynamic temporal relationship during emotion viewing. Our findings emphasize the need to apply time-sensitive measures in ecologically valid research, which may index etiological mechanisms of social difficulties in ASD.

Are depressive symptoms linked to a reduced pupillary response to novel positive information?-An eye tracking proof-of-concept study

Introduction

Depressive symptoms have been linked to difficulties in revising established negative beliefs in response to novel positive information. Recent predictive processing accounts have suggested that this bias in belief updating may be related to a blunted processing of positive prediction errors at the neural level. In this proof-of-concept study, pupil dilation in response to unexpected positive emotional information was examined as a psychophysiological marker of an attenuated processing of positive prediction errors associated with depressive symptoms.

Methods

Participants (N = 34) completed a modified version of the emotional Bias Against Disconfirmatory Evidence (BADE) task in which scenarios initially suggest negative interpretations that are later either confirmed or disconfirmed by additional information. Pupil dilation in response to the confirmatory and disconfirmatory information was recorded.

Results

Behavioral results showed that depressive symptoms were related to difficulties in revising negative interpretations despite disconfirmatory positive information. The eye tracking results pointed to a reduced pupil response to unexpected positive information among people with elevated depressive symptoms.

Discussion

Altogether, the present study demonstrates that the adapted emotional BADE task can be appropriate for examining psychophysiological aspects such as changes in pupil size along with behavioral responses. Furthermore, the results suggest that depression may be characterized by deviations in both behavioral (i.e., reduced updating of negative beliefs) and psychophysiological (i.e., decreased pupil dilation) responses to unexpected positive information. Future work should focus on a larger sample including clinically depressed patients to further explore these findings.

Temporal characteristics of facial ensemble in individuals with autism spectrum disorder: examination from arousal and attentional allocation

Introduction

Individuals with Autism Spectrum Disorder (ASD) show atypical recognition of facial emotions, which has been suggested to stem from arousal and attention allocation. Recent studies have focused on the ability to perceive an average expression from multiple spatially different expressions. This study investigated the effect of autistic traits on temporal ensemble, that is, the perception of the average expression from multiple changing expressions.

Methods

We conducted a simplified temporal-ensemble task and analyzed behavioral responses, pupil size, and viewing times for eyes of a face. Participants with and without diagnosis of ASD viewed serial presentations of facial expressions that randomly switched between emotional and neutral. The temporal ratio of the emotional expressions was manipulated. The participants estimated the intensity of the facial emotions for the overall presentation.

Results

We obtained three major results: (a) many participants with ASD were less susceptible to the ratio of anger expression for temporal ensembles, (b) they produced significantly greater pupil size for angry expressions (within-participants comparison) and smaller pupil size for sad expressions (between-groups comparison), and (c) pupil size and viewing time to eyes were not correlated with the temporal ensemble.

Discussion

These results suggest atypical temporal integration of anger expression and arousal characteristics in individuals with ASD; however, the atypical integration is not fully explained by arousal or attentional allocation.

Slower Peak Pupillary Response to Emotional Faces in Parents of Autistic Individuals

Background

Atypical autonomic arousal has been consistently documented in autism spectrum disorder (ASD) and is thought to contribute to the social-communication phenotype of ASD. Some evidence suggests that clinically unaffected first-degree relatives of autistic individuals may also show subtle differences in indices of autonomic arousal, potentially implicating heritable pathophysiological mechanisms in ASD. This study examined pupillary responses in parents of autistic individuals to investigate evidence that atypical autonomic arousal might constitute a subclinical physiological marker of ASD heritability within families of autistic individuals.

Methods

Pupillary responses to emotional faces were measured in 47 ASD parents and 20 age-matched parent controls. Macro-level pupillary responses (e.g., mean, peak, latency to peak) and dynamic pupillary responses over the course of the stimulus presentation were compared between groups, and in relationship to subclinical ASD-related features in ASD parents. A small ASD group (n = 20) and controls (n = 17) were also included for exploratory analyses of parent–child correlations in pupillary response.

Results

Parents of autistic individuals differed in the time course of pupillary response, exhibiting a later primary peak response than controls. In ASD parents, slower peak response was associated with poorer pragmatic language and larger peak response was associated with poorer social cognition. Exploratory analyses revealed correlations between peak pupillary responses in ASD parents and mean and peak pupillary responses in their autistic children.

Conclusion

Differences in pupillary responses in clinically unaffected parents, together with significant correlations with ASD-related features and significant parent–child associations, suggest that pupillary responses to emotional faces may constitute an objective physiological marker of ASD genetic liability, with potential to inform the mechanistic underpinnings of ASD symptomatology.

Automatic processing of emotional images and psychopathic personality traits

Psychopathy is associated with a deficit in affective processes and might be reflected in the inability to extract the emotional content of a stimulus. Across two experiments, we measured the interference effect from emotional images that were irrelevant to the processing of simultaneous target stimuli and examined if this interference was moderated by psychometrically defined traits of psychopathy. In Experiment 1, we showed this emotional distraction effect was reduced as a function of psychopathic traits related to cold-heartedness and occurred for both positively- and negatively-valenced images. Experiment 2 attempted to test the automaticity of the effects by presenting the emotional stimuli briefly so that the emotion was difficult to report. Again, high visibility images produced strong effects that were moderated by the cold-heatedness/meanness traits of psychopathy, but the low-visibility images did not evoke the emotional distractor effect. Our results strongly support the notion that psychopathic traits related to cold-heartedness/meanness are associated with an inability to automatically process the emotional content of images.

Reduced Pupil Oscillation During Facial Emotion Judgment in People with Autism Spectrum Disorder

People with autism spectrum disorder (ASD) show abnormal face perception and emotion recognition. However, it remains largely unknown whether these differences are associated with abnormal physiological responses when viewing faces. In this study, we employed a sensitive emotion judgment task and conducted a detailed investigation of pupil dilation/constriction and oscillation in high-functioning adult participants with ASD and matched controls. We found that participants with ASD showed normal pupil constriction to faces; however, they demonstrated reduced pupil oscillation, which was independent of stimulus properties and participants' perception of the emotion. Together, our results have revealed an abnormal physiological response to faces in people with ASD, which may in turn be associated with impaired face perception previously found in many studies.

Pupillary Responses Obey Emmert's Law and Co-vary with Autistic Traits

We measured the pupil response to a light stimulus subject to a size illusion and found that stimuli perceived as larger evoke a stronger pupillary response. The size illusion depends on combining retinal signals with contextual 3D information; contextual processing is thought to vary across individuals, being weaker in individuals with stronger autistic traits. Consistent with this theory, autistic traits correlated negatively with the magnitude of pupil modulations in our sample of neurotypical adults; however, psychophysical measurements of the illusion did not correlate with autistic traits, or with the pupil modulations. This shows that pupillometry provides an accurate objective index of complex perceptual processes, particularly useful for quantifying interindividual differences, and potentially more informative than standard psychophysical measures.

Investigating automatic emotion processing in boys with autism via eye tracking and facial mimicry recordings

Difficulties in automatic emotion processing in individuals with autism spectrum disorder (ASD) might remain concealed in behavioral studies due to compensatory strategies. To gain more insight in the mechanisms underlying facial emotion recognition, we recorded eye tracking and facial mimicry data of 20 school-aged boys with ASD and 20 matched typically developing controls while performing an explicit emotion recognition task. Proportional looking times to specific face regions (eyes, nose, and mouth) and face exploration dynamics were analyzed. In addition, facial mimicry was assessed. Boys with ASD and controls were equally capable to recognize expressions and did not differ in proportional looking times, and number and duration of fixations. Yet, specific facial expressions elicited particular gaze patterns, especially within the control group. Both groups showed similar face scanning dynamics, although boys with ASD demonstrated smaller saccadic amplitudes. Regarding the facial mimicry, we found no emotion specific facial responses and no group differences in the responses to the displayed facial expressions. Our results indicate that boys with and without ASD employ similar eye gaze strategies to recognize facial expressions. Smaller saccadic amplitudes in boys with ASD might indicate a less exploratory face processing strategy. Yet, this slightly more persistent visual scanning behavior in boys with ASD does not imply less efficient emotion information processing, given the similar behavioral performance. Results on the facial mimicry data indicate similar facial responses to emotional faces in boys with and without ASD. LAY SUMMARY: We investigated (i) whether boys with and without autism apply different face exploration strategies when recognizing facial expressions and (ii) whether they mimic the displayed facial expression to a similar extent. We found that boys with and without ASD recognize facial expressions equally well, and that both groups show similar facial reactions to the displayed facial emotions. Yet, boys with ASD visually explored the faces slightly less than the boys without ASD.

Combined frequency-tagging EEG and eye-tracking measures provide no support for the "excess mouth/diminished eye attention" hypothesis in autism

BACKGROUND

Scanning faces is important for social interactions. Difficulty with the social use of eye contact constitutes one of the clinical symptoms of autism spectrum disorder (ASD). It has been suggested that individuals with ASD look less at the eyes and more at the mouth than typically developing (TD) individuals, possibly due to gaze aversion or gaze indifference. However, eye-tracking evidence for this hypothesis is mixed. While gaze patterns convey information about overt orienting processes, it is unclear how this is manifested at the neural level and how relative covert attention to the eyes and mouth of faces might be affected in ASD.

METHODS

We used frequency-tagging EEG in combination with eye tracking, while participants watched fast flickering faces for 1-min stimulation sequences. The upper and lower halves of the faces were presented at 6 Hz and 7.5 Hz or vice versa in different stimulation sequences, allowing to objectively disentangle the neural saliency of the eyes versus mouth region of a perceived face. We tested 21 boys with ASD (8-12 years old) and 21 TD control boys, matched for age and IQ.

RESULTS

Both groups looked longer at the eyes than the mouth, without any group difference in relative fixation duration to these features. TD boys looked significantly more to the nose, while the ASD boys looked more outside the face. EEG neural saliency data partly followed this pattern: neural responses to the upper or lower face half were not different between groups, but in the TD group, neural responses to the lower face halves were larger than responses to the upper part. Face exploration dynamics showed that TD individuals mostly maintained fixations within the same facial region, whereas individuals with ASD switched more often between the face parts.

LIMITATIONS

Replication in large and independent samples may be needed to validate exploratory results.

CONCLUSIONS

Combined eye-tracking and frequency-tagged neural responses show no support for the excess mouth/diminished eye gaze hypothesis in ASD. The more exploratory face scanning style observed in ASD might be related to their increased feature-based face processing style.

Autism spectrum disorder and pupillometry: A systematic review and meta-analysis

Pupillometry, measuring pupil size and reactivity, has been proposed as a measure of autonomic nervous system functioning, the latter which might be altered in individuals with autism spectrum disorder (ASD). This study aims to evaluate if pupillary responses differ in individuals with and without ASD. After performing a systematic literature search, we conducted a meta-analysis and constructed a qualitative synthesis. The meta-analysis shows a longer latency of the pupil response in the ASD-group as a substantial group difference, with a Hedges' g of 1.03 (95% CI 0.49-1.56, p = 0.008). Evidence on baseline pupil size and amplitude change is conflicting. We used the framework method to perform a qualitative evaluation of these differences. Explanations for the group differences vary between studies and are inconclusive, but many authors point to involvement of the autonomous nervous system and more specifically the locus coeruleus-norepinephrine system. Pupillometry reveals differences between people with and without ASD, but the exact meaning of these differences remains unknown. Future studies should align research designs and investigate a possible effect of maturation.

The developmental origins of subliminal face processing

Sensitive responding to facial information is of key importance during human social interactions. Research shows that adults glean much information from another person's face without conscious perception, attesting to the robustness of face processing in the service of adaptive social functioning. Until recently, it was unclear whether such subliminal face processing is an outcome of extensive learning, resulting in adult face processing skills, or an early defining feature of human face processing. Here, we review recent research examining the early ontogeny and brain correlates of subliminal face processing, demonstrating that subliminal face processing: (1) emerges during the first year of life; (2) is multifaceted in response to transient (gaze, emotion) and stable (trustworthiness) facial cues; (3) systematically elicits frontal brain responses linked to attention allocation. The synthesized research suggests that subliminal face processing emerges early in human development and thus may play a foundational role during human social interactions. This offers a fresh look at the ontogenetic origins of unconscious face processing and informs theoretical accounts of human sociality.

Pupil Response to Affective Stimuli: a Biomarker of Early Conduct Problems in Young Children

Childhood conduct problems have been associated with reduced autonomic arousal to negative cues indicative of an insensitivity to aversive stimuli, with mixed evidence in response to positive cues. Autonomic arousal to affective stimuli has traditionally been measured through galvanic skin responses and heart-rate, despite evidence that pupillometry is more reliable and practically beneficial (i.e., no wires are attached to the participant). The current study is the first to examine abnormal pupillary responsivity to affective stimuli as a biomarker for childhood conduct problems. We measured pupil reactivity to negative, positive and neutral images in 131 children aged 4-7 years, who were referred by their teachers for being at risk of future psychopathology. We assessed relationships between pupil response to the images and teacher-rated scores on the Strengths and Difficulties Questionnaire (SDQ), which indexed child conduct problems and their overlapping emotional, behavioural and social difficulties. Reduced pupil dilation to negative images was associated with significantly increased conduct, hyperactivity, emotional and peer problems, as well as reduced prosocial behaviour. Composite scores for disruptive behaviour and emotional difficulties both uniquely predicted blunted pupil response to negative threat stimuli; there were no relations with pupil responses to positive images. These findings highlight that blunted pupil responsivity to negative stimuli serves as a biomarker for early disruptive behavioural problems and affective difficulties. Pupillometry offers an inexpensive, fast and non-intrusive measure to help identify children who are showing early disruptive behaviour or experiencing affective difficulties, which can provide opportunities for preventative intervention to avoid further psychopathology.

Uncharacteristic Task-Evoked Pupillary Responses Implicate Atypical Locus Ceruleus Activity in Autism

Autism spectrum disorder (ASD) is characterized partly by atypical attentional engagement, reflected in exaggerated and variable responses to sensory stimuli. Attentional engagement is known to be regulated by the locus ceruleus (LC). Moderate baseline LC activity globally dampens neural responsivity and is associated with adaptive deployment and narrowing of attention to task-relevant stimuli. In contrast, increased baseline LC activity enhances neural responsivity across cortex and widening of attention to environmental stimuli regardless of their task relevance. Given attentional atypicalities in ASD, this study is the first to evaluate whether, under different attentional task demands, individuals with ASD exhibit a different profile of LC activity compared with typically developing controls. Males and females with ASD and age- and gender-matched controls participated in a one-back letter detection test while task-evoked pupillary responses, an established correlate for LC activity, were recorded. Participants completed this task in two conditions, either in the absence or presence of distractor auditory tones. Compared with controls, individuals with ASD evinced atypical pupillary responses in the presence versus absence of distractors. Notably, this atypical pupillary profile was evident despite the fact that both groups exhibited equivalent task performance. Moreover, between-group differences in pupillary responses were observed specifically in response to task-relevant events, providing confirmation that the group differences most likely were specifically associated with distinctions in LC activity. These findings suggest that individuals with ASD show atypical modulation of LC activity with changes in attentional demands, offering a possible mechanistic and neurobiological account for attentional atypicalities in ASD.SIGNIFICANCE STATEMENT Individuals with autism spectrum disorder (ASD) exhibit atypical attentional behaviors, including altered sensory responses and atypical fixedness, but the neural mechanism underlying these behaviors remains elusive. One candidate mechanism is atypical locus ceruleus (LC) activity, as the LC plays a critical role in attentional modulation. Specifically, LC activity is involved in regulating the trade-off between environmental exploration and focused attention. This study shows that, under tightly controlled conditions, task-evoked pupil responses, an LC activity proxy, are lower in individuals with ASD than in controls, but only in the presence of task-irrelevant stimuli. This suggests that individuals with ASD evince atypical modulation of LC activity in accordance with changes in attentional demands, offering a mechanistic account for attentional atypicalities in ASD.

Atypical Social Attention and Emotional Face Processing in Autism Spectrum Disorder: Insights From Face Scanning and Pupillometry

Social attention deficits are a hallmark characteristic within autism spectrum disorder (ASD) and have been hypothesized to have cascading effects on emotion recognition. Eye-tracking methodology has emerged as a potentially reliable, feasible, and sensitive biomarker for examining core phenotypic features of ASD; however, these findings are mixed with regards to measuring treatment change in clinical trials. The present study aimed to assess the utility of an eye-tracking paradigm to discriminate between clinical groups in social attention and emotion recognition through face scanning and pupillometry. The present study also assessed the reliability of this paradigm within the ASD sample to further our understanding of the utility of eye-tracking for future clinical trials. Participants included 42 individuals with ASD, 29 developmental disability (DD) controls, and 62 typically developing (TD) controls between 3 and 25 years of age. An emotional faces eye-tracking paradigm was administered to all participants, with the ASD group completing the paradigm a second time approximately 2 months later. Participants' average proportion of looking and number of fixations to specific areas of interest (AOI) were examined along with changes in pupil reactivity while viewing different emotional faces. Results suggest atypical face-scanning through a reduced proportion of looking and the number of fixations toward the eyes in the ASD group regardless of the emotion that was presented. Further, pupillometry measures were able to detect increases in pupil dilation to happy faces in the ASD group. Lastly, test-retest reliability coefficients varied between the poor and excellent range based on the mechanism assessed, with the proportion of looking demonstrating the highest reliability coefficients. These findings build on the promise of eye-tracking as a feasible and reliable biomarker for identifying social attention and emotion recognition deficits in ASD. Detecting differences in emotion recognition explicitly through facial scanning was not as clear. Specific mechanisms within the eye-tracking paradigm may be viable options for assessing treatment-specific outcomes.

The Mimicry Among Us: Intra- and Inter-Personal Mechanisms of Spontaneous Mimicry

This review explores spontaneous mimicry in the context of three questions. The first question concerns the role of spontaneous mimicry in processing conceptual information. The second question concerns the debate whether spontaneous mimicry is driven by simple associative processes or reflects higher-order processes such as goals, intentions, and social context. The third question addresses the implications of these debates for understanding atypical individuals and states. We review relevant literature and argue for a dynamic, context-sensitive role of spontaneous mimicry in social cognition and behavior. We highlight how the modulation of mimicry is often adaptive but also point out some cases of maladaptive modulations that impair an individuals’ engagement in social life.

Fast Periodic Visual Stimulation EEG Reveals Reduced Neural Sensitivity to Fearful Faces in Children with Autism

We objectively quantified the neural sensitivity of school-aged boys with and without autism spectrum disorder (ASD) to detect briefly presented fearful expressions by combining fast periodic visual stimulation with frequency-tagging electroencephalography. Images of neutral faces were presented at 6 Hz, periodically interleaved with fearful expressions at 1.2 Hz oddball rate. While both groups equally display the face inversion effect and mainly rely on information from the mouth to detect fearful expressions, boys with ASD generally show reduced neural responses to rapid changes in expression. At an individual level, fear discrimination responses predict clinical status with an 83% accuracy. This implicit and straightforward approach identifies subtle deficits that remain concealed in behavioral tasks, thereby opening new perspectives for clinical diagnosis.

Pupil dilation to emotional expressions in adolescent social anxiety disorder is related to treatment outcome

Atypical attention to potential social threats, such as emotional faces, may be one of the core mechanisms underlying social anxiety disorder (SAD). Pupil dilation is an index of locus coreuleus-noradrenergic activity, and closely linked to attention. In the present study, pupil dilation was studied in adolescents with SAD (N = 26; 22 Female) before the onset of a 12-week cognitive behavioral treatment, and in healthy controls (N = 23). Stimuli were faces with angry or happy emotional expressions. Contrary to our hypothesis, the SAD group did not show hyper-responsiveness to angry compared to happy faces. Instead, an atypical time course of the pupil dilation response was found, resulting in an attenuated response during late time stages. Larger pupil dilation amplitude to happy faces before treatment was related to worse treatment response. These results contribute significantly to our understanding of the mechanisms underlying adolescent SAD.

The Characteristics of Intelligence Profile and Eye Gaze in Facial Emotion Recognition in Mild and Moderate Preschoolers With Autism Spectrum Disorder

Childhood autism spectrum disorder (ASD) can easily be misdiagnosed, due to the nonspecific social and communicational deficits associated with the disorder. The present study attempted to profile the mental development and visual attention toward emotion among preschool children with mild or moderate ASD who were attending mainstream kindergartens. A total of 21 children (17 boys and 4 girls) diagnosed with mild or moderate ASD selected from 5,178 kindergarteners from the Xi'an city were recruited. Another group of 21 typically developing (TD) children who were matched with age, gender, and class served as controls. All children were assessed using the Griffiths Mental Development Scales-Chinese (GDS-C), and their social visual attention was assessed during watching 20 ecologically valid film scenes by using eye tracking technique. The results showed that ASD children had lower mental development scores in the Locomotor, Personal-Social, Language, Performance, and Practical Reasoning subscales than the TD peers. Moreover, deficits in recognizing emotions from facial expressions based on naturalistic scene stimuli with voice were found for ASD children. The deficits were significantly correlated with their ability in social interaction and development quotient in ASD group. ASD children showed atypical eye-gaze pattern when compared to TD children during facial emotion expression task. Children with ASD had reduced visual attention to facial emotion expression, especially for the eye region. The findings confirmed the deficits of ASD children in real life multimodal of emotion recognition, and their atypical eye-gaze pattern for emotion recognition. Parents and teachers of children with mild or moderate ASD should make informed educational decisions according to their level of mental development. In addition, eye tracking technique might clinically help provide evidence diagnosing children with mild or moderate ASD.

Neuromodulation and a Reconceptualization of Autism Spectrum Disorders: Using the Locus Coeruleus Functioning as an Exemplar

The Autism Spectrum Disorders (ASD) are a heterogeneous group of developmental disorders. Although, ASD can be reliably diagnosed, the etiology, pathophysiology, and treatment targets remain poorly characterized. While there are many atypical findings in anatomy, genetics, connectivity, and other biologic parameters, there remains no discreet hypothesis to explain the core signs as well as the very frequent comorbidities. Due to this, designing targets for treatments can only be done by assuming each symptom is a result of a discreet abnormality which is likely not the case. Neuronal circuity remains a major focus of research but rarely taking into account the functioning of the brain is highly dependent on various systems, including the neuromodulatory substances originating in the midbrain. A hypothesis is presented which explores the possibility of explaining many of the symptoms found in ASD in terms of inefficient neuromodulation using the functioning of the locus coeruleus and norepinephrine (LC/NE) as exemplars. The basic science of LC/NE is reviewed. Several functions found to be impaired in ASD including learning, attention, sensory processing, emotional regulation, autonomic functioning, adaptive and repetitive behaviors, sleep, language acquisition, initiation, and prompt dependency are examined in terms of the functioning of the LC/NE system. Suggestions about possible treatment directions are explored.

Unconscious Psychological Treatments for Physiological Survival Circuits

The idea of targeting unconscious or implicit processes in psychological treatments is not new, but until recently it has not been easy to manipulate these processes without also engaging consciousness. Here we review how this is possible, using various modern cognitive neuroscience methods including a technique known as Decoded Neural-Reinforcement. We discuss the general advantages of this approach, such as how it can facilitate double-blind placebo-controlled studies, and minimize premature patient dropouts in the treatment of fear. We also speculate how this may generalize to other similar physiological survival processes.

Pupil response to social-emotional material is associated with rumination and depressive symptoms in adults with autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is marked by repetitive thinking and high rates of depression. Understanding the extent to which repetitive negative thinking in ASD reflects autistic stereotypy versus general depressive thinking patterns (e.g., rumination) could help guide treatment research to improve emotional health in ASD. We compared associations between rumination, depressive symptoms, and pupil response to social-emotional material in adults with ASD and typically developing (TD) adults with and without depression.

METHODS

N = 53 verbally fluent young adults were recruited to three cohorts: ASD, n = 21; TD-depressed, n = 13; never-depressed TD-controls, n = 19. Participants completed Ruminative Response Scale and Beck Depression Inventory self-reports and a passive-viewing task employing emotionally-expressive faces, during which pupillary motility was assessed to quantify cognitive-affective load. Main and interactive effects of cohort, emotion condition, and time on pupil amplitude were tested via a linear mixed effects analysis of variance using restricted maximum likelihood estimation. Similar procedures were used to test for effects of rumination and depressive symptoms on pupil amplitude over time within ASD.

RESULTS

Responsive pupil dilation in the ASD cohort tended to be significantly lower than TD-depressed initially but increased to comparable levels by trial end. When viewing sad faces, individuals with ASD who had higher depression scores resembled TD-depressed participants' faster, larger, and sustained pupil response. Within ASD, depressive symptoms uniquely predicted early pupil response to sad faces, while rumination and depression scores each independently predicted sustained pupil response.

CONCLUSIONS

People with elevated depressive symptoms appear to have faster and greater increases in pupil-indexed neural activation following sad stimuli, regardless of ASD status, suggesting the utility of conceptualizing rumination as depression-like in treatment. Ruminative processes may increase more slowly in ASD, suggesting the potential utility of interventions that decrease reactions before they are uncontrollable. Findings also reinforce the importance of testing for effects of internalizing variables in broader ASD research.

Self-Report and Brain Indicators of Impaired Emotion Regulation in the Broad Autism Spectrum

Although not used as a diagnostic criterion, impaired emotion regulation is frequently observed in autism. The present study examined self-reported use of emotion regulation strategies in individuals scoring low or high on autistic traits. In addition, the late positive potential, which is sensitive to emotional arousal, was used to examine the effect of one strategy, reappraisal. Reporting more autistic traits was related to using more maladaptive and fewer adaptive emotion regulation strategies. Across both groups, no attenuation of the late positive potential during downregulation of unpleasant pictures was found, possibly because of the used valence-changing reappraisal operationalisation. Hence, although self-report indicated impaired emotion regulation in individuals high on autistic traits, electrophysiological findings could not confirm this.

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.

Altered Pre-Ejection Period Response to Social Evaluative Threat in Adolescents with Autism Spectrum Disorder

INTRODUCTION

The autonomic nervous system (ANS) is involved in regulating social behavior; Autism Spectrum Disorder (ASD) is characterized by alterations in social behavior and reduced physiological response to threat. We hypothesized that adolescents with ASD would show reduced ANS response to social threat.

METHODS

Eighteen males with ASD and thirteen males with typical development (TD), ages 12 to 17, completed a social threat paradigm while wearing an impedance cardiography apparatus. We calculated pre-ejection period (PEP) and tested for between-group differences in PEP response to social threat. We also conducted correlation analyses between PEP change scores and clinical symptom scales.

RESULTS

There was an effect of diagnosis on change in PEP from baseline to the onset of social threat (F=7.60, p=0.01), with greater changes in PEP in TD compared to ASD. PEP change score and the Social Communication Questionnaire (r=0.634, p=0.005) and the ADHD Problems Subscale of the Child Behavior Checklist (r=0.568, p=0.014) were correlated.

CONCLUSIONS

These findings suggest reduced arousal in response to social threat in ASD, with preliminary evidence that reduced sympathetic activation is associated with increased social behavior symptoms.

As Far as the Eye Can See: Relationship between Psychopathic Traits and Pupil Response to Affective Stimuli

Psychopathic individuals show a range of affective processing deficits, typically associated with the interpersonal/affective component of psychopathy. However, previous research has been inconsistent as to whether psychopathy, within both offender and community populations, is associated with deficient autonomic responses to the simple presentation of affective stimuli. Changes in pupil diameter occur in response to emotionally arousing stimuli and can be used as an objective indicator of physiological reactivity to emotion. This study used pupillometry to explore whether psychopathic traits within a community sample were associated with hypo-responsivity to the affective content of stimuli. Pupil activity was recorded for 102 adult (52 female) community participants in response to affective (both negative and positive affect) and affectively neutral stimuli, that included images of scenes, static facial expressions, dynamic facial expressions and sound-clips. Psychopathic traits were measured using the Triarchic Psychopathy Measure. Pupil diameter was larger in response to negative stimuli, but comparable pupil size was demonstrated across pleasant and neutral stimuli. A linear relationship between subjective arousal and pupil diameter was found in response to sound-clips, but was not evident in response to scenes. Contrary to predictions, psychopathy was unrelated to emotional modulation of pupil diameter across all stimuli. The findings were the same when participant gender was considered. This suggests that psychopathy within a community sample is not associated with autonomic hypo-responsivity to affective stimuli, and this effect is discussed in relation to later defensive/appetitive mobilisation deficits.

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.

Autistic traits modulate conscious and nonconscious face perception

Difficulty with emotion perception is a core feature of autism spectrum disorder (ASD) that is also associated with the broader autism phenotype. The current study explored the neural underpinnings of conscious and nonconscious perceptions of affect in typically developing individuals with varying levels of autistic-like traits, as measured by the Autism Quotient (AQ). We investigated the relationship between autistic traits and face processing efficiency using event-related potentials (ERPs). In 20 typically developing adults, we utilized ERPs (the P100, N170, and P300) to measure differences in face processing for emotional faces that were presented either (a) too quickly to reach conscious awareness (16 ms) or (b) slowly enough to be consciously observed (200 ms). All individuals evidenced increased P100 and P300 amplitude and shorter N170 latencies for nonconscious versus consciously presented faces. Individuals with high AQ scores evidenced delayed ERP components. Nonconsciously perceived emotional faces elicited enhanced neural responses regardless of AQ score. Higher levels of autistic traits were associated with inefficient face perception (i.e., longer latency of ERP components). This delay parallels processing delays observed in ASD. These data suggest that inefficient social perception is present in individuals with subclinical levels of social impairment.

Others' emotions teach, but not in autism: an eye-tracking pupillometry study

BACKGROUND

Much research has investigated deficit in emotional reactivity to others in people with autism, but scant attention has been paid to how this deficit affects their own reactions to features of their environment (objects, events, practices, etc.). The present study presents a preliminary analysis on whether calibrating one's own emotional reactions to others' emotional reactions about features of the world, a process we term social-emotional calibration, is disrupted in autism.

METHODS

To examine this process, we used a novel eye-tracking pupillometry paradigm in which we showed 20 preschoolers with autism and 20 matched typically developing preschoolers' videos of an actor opening a box and reacting to the occluded object inside, with fear or happiness. We expected preschoolers to come to perceive the box as containing a positive or threatening stimulus through emotionally calibrating to the actor's emotional expressions. Children's mean pupil diameter (indicating emotional reactivity) was measured whilst viewing an up-close, visually identical image of the box before and then after the scene, and this difference was taken as an index of social-emotional calibration and compared between groups.

RESULTS

Whilst the typically developing preschoolers responded more emotionally to the box after, compared to before the scene (as indexed by an increase in pupil size), those with autism did not, suggesting their reaction to the object was not affected by the actor's emotional expressions. The groups did not differ in looking duration to the emotional expressions; thus, the pupil dilation findings cannot be explained by differences in visual attention. More social-emotional calibration on the happy condition was associated with less severe autism symptoms.

CONCLUSIONS

Through the measurement of physiological reactivity, findings suggest social-emotional calibration is diminished in children with autism, with calibration to others' positive emotions as particularly important. This study highlights a possible mechanism by which individuals with autism develop idiosyncratic reactions to features of their environment, which is likely to impact their active and harmonious participation on social and cultural practices from infancy, throughout the lifespan. More research is needed to examine the mediators and developmental sequence of this tendency to emotionally calibrate to others' feelings about the world.

The pupil's response to affective pictures: Role of image duration, habituation, and viewing mode

The pupil has been shown to be sensitive to the emotional content of stimuli. We examined this phenomenon by comparing fearful and neutral images carefully matched in the domains of luminance, image contrast, image color, and complexity of content. The pupil was more dilated after viewing affective pictures, and this effect was (a) shown to be independent of the presentation time of the images (from 100–3,000 ms), (b) not diminished by repeated presentations of the images, and (c) not affected by actively naming the emotion of the stimuli in comparison to passive viewing. Our results show that the emotional modulation of the pupil is present over a range of variables that typically vary from study to study (image duration, number of trials, free viewing vs. task), and encourages the use of pupillometry as a measure of emotional processing in populations where alternative techniques may not be appropriate.

Greater Pupil Size in Response to Emotional Faces as an Early Marker of Social-Communicative Difficulties in Infants at High Risk for Autism

When scanning faces, individuals with autism spectrum disorder (ASD) have shown reduced visual attention (e.g., less time on eyes) and atypical autonomic responses (e.g., heightened arousal). To understand how these differences might explain sub-clinical variability in social functioning, 9-month-olds, with or without a family history of ASD, viewed emotionally-expressive faces, and gaze and pupil diameter (a measure of autonomic activation) were recorded using eye-tracking. Infants at high-risk for ASD with no subsequent clinical diagnosis (HRA-) and low-risk controls (LRC) showed similar face scanning and attention to eyes and mouth. Attention was overall greater to eyes than mouth, but this varied as a function of the emotion presented. HRA- showed significantly larger pupil size than LRC. Correlations between scanning at 9 months, pupil size at 9 months, and 18-month social-communicative behavior, revealed positive associations between pupil size and attention to both face and eyes at 9 months in LRC, and a negative association between 9-month pupil size and 18-month social-communicative behavior in HRA-. The present findings point to heightened autonomic arousal in HRA-. Further, with greater arousal relating to worse social-communicative functioning at 18 months, this work points to a mechanism by which unaffected siblings might develop atypical social behavior.

Pupil size directly modulates the feedforward response in human primary visual cortex independently of attention

Controversy revolves around the question of whether psychological factors like attention and emotion can influence the initial feedforward response in primary visual cortex (V1). Although traditionally, the electrophysiological correlate of this response in humans (the C1 component) has been found to be unaltered by psychological influences, a number of recent studies have described attentional and emotional modulations. Yet, research into psychological effects on the feedforward V1 response has neglected possible direct contributions of concomitant pupil-size modulations, which are known to also occur under various conditions of attentional load and emotional state. Here we tested the hypothesis that such pupil-size differences themselves directly affect the feedforward V1 response. We report data from two complementary experiments, in which we used procedures that modulate pupil size without differences in attentional load or emotion while simultaneously recording pupil-size and EEG data. Our results confirm that pupil size indeed directly influences the feedforward V1 response, showing an inverse relationship between pupil size and early V1 activity. While it is unclear in how far this effect represents a functionally-relevant adaptation, it identifies pupil-size differences as an important modulating factor of the feedforward response of V1 and could hence represent a confounding variable in research investigating the neural influence of psychological factors on early visual processing.

Approaches to studying and manipulating the enteric microbiome to improve autism symptoms

There is a growing body of scientific evidence that the health of the microbiome (the trillions of microbes that inhabit the human host) plays an important role in maintaining the health of the host and that disruptions in the microbiome may play a role in certain disease processes. An increasing number of research studies have provided evidence that the composition of the gut (enteric) microbiome (GM) in at least a subset of individuals with autism spectrum disorder (ASD) deviates from what is usually observed in typically developing individuals. There are several lines of research that suggest that specific changes in the GM could be causative or highly associated with driving core and associated ASD symptoms, pathology, and comorbidities which include gastrointestinal symptoms, although it is also a possibility that these changes, in whole or in part, could be a consequence of underlying pathophysiological features associated with ASD. However, if the GM truly plays a causative role in ASD, then the manipulation of the GM could potentially be leveraged as a therapeutic approach to improve ASD symptoms and/or comorbidities, including gastrointestinal symptoms. One approach to investigating this possibility in greater detail includes a highly controlled clinical trial in which the GM is systematically manipulated to determine its significance in individuals with ASD. To outline the important issues that would be required to design such a study, a group of clinicians, research scientists, and parents of children with ASD participated in an interdisciplinary daylong workshop as an extension of the 1st International Symposium on the Microbiome in Health and Disease with a Special Focus on Autism (www.microbiome-autism.com). The group considered several aspects of designing clinical studies, including clinical trial design, treatments that could potentially be used in a clinical trial, appropriate ASD participants for the clinical trial, behavioral and cognitive assessments, important biomarkers, safety concerns, and ethical considerations. Overall, the group not only felt that this was a promising area of research for the ASD population and a promising avenue for potential treatment but also felt that further basic and translational research was needed to clarify the clinical utility of such treatments and to elucidate possible mechanisms responsible for a clinical response, so that new treatments and approaches may be discovered and/or fostered in the future.