A novel functional brain imaging endophenotype of autism: the neural response to facial expression of emotion

Endophenotype trait domains for advancing gene discovery in autism spectrum disorder

Autism spectrum disorder (ASD) is associated with a diverse range of etiological processes, including both genetic and non-genetic causes. For a plurality of individuals with ASD, it is likely that the primary causes involve multiple common inherited variants that individually account for only small levels of variation in phenotypic outcomes. This genetic landscape creates a major challenge for detecting small but important pathogenic effects associated with ASD. To address similar challenges, separate fields of medicine have identified endophenotypes, or discrete, quantitative traits that reflect genetic likelihood for a particular clinical condition and leveraged the study of these traits to map polygenic mechanisms and advance more personalized therapeutic strategies for complex diseases. Endophenotypes represent a distinct class of biomarkers useful for understanding genetic contributions to psychiatric and developmental disorders because they are embedded within the causal chain between genotype and clinical phenotype, and they are more proximal to the action of the gene(s) than behavioral traits. Despite their demonstrated power for guiding new understanding of complex genetic structures of clinical conditions, few endophenotypes associated with ASD have been identified and integrated into family genetic studies. In this review, we argue that advancing knowledge of the complex pathogenic processes that contribute to ASD can be accelerated by refocusing attention toward identifying endophenotypic traits reflective of inherited mechanisms. This pivot requires renewed emphasis on study designs with measurement of familial co-variation including infant sibling studies, family trio and quad designs, and analysis of monozygotic and dizygotic twin concordance for select trait dimensions. We also emphasize that clarification of endophenotypic traits necessarily will involve integration of transdiagnostic approaches as candidate traits likely reflect liability for multiple clinical conditions and often are agnostic to diagnostic boundaries. Multiple candidate endophenotypes associated with ASD likelihood are described, and we propose a new focus on the analysis of "endophenotype trait domains" (ETDs), or traits measured across multiple levels (e.g., molecular, cellular, neural system, neuropsychological) along the causal pathway from genes to behavior. To inform our central argument for research efforts toward ETD discovery, we first provide a brief review of the concept of endophenotypes and their application to psychiatry. Next, we highlight key criteria for determining the value of candidate endophenotypes, including unique considerations for the study of ASD. Descriptions of different study designs for assessing endophenotypes in ASD research then are offered, including analysis of how select patterns of results may help prioritize candidate traits in future research. We also present multiple candidate ETDs that collectively cover a breadth of clinical phenomena associated with ASD, including social, language/communication, cognitive control, and sensorimotor processes. These ETDs are described because they represent promising targets for gene discovery related to clinical autistic traits, and they serve as models for analysis of separate candidate domains that may inform understanding of inherited etiological processes associated with ASD as well as overlapping neurodevelopmental disorders.

Should perception of emotions be classified according to threat detection rather than emotional valence? An updated meta-analysis for a whole-brain atlas of emotional faces processing

BACKGROUND

Human navigation of social interactions relies on the processing of emotion on faces. This meta-analysis aimed to produce an updated brain atlas of emotional face processing from whole-brain studies based on a single emotional face-viewing paradigm (PROSPERO CRD42022251548).

METHODS

We conducted a systematic literature search of Embase, MEDLINE and PsycINFO from May 2008 to October 2021. We used seed-based d mapping with permutation of subject images to conduct a quantitative meta-analysis of functional neuroimaging contrasts between emotional (e.g., angry, happy) and neutral faces. We conducted agglomerative hierarchical clustering of meta-analytic map contrasts of emotional faces relative to neutral faces. We investigated lateralization of emotional face processing.

RESULTS

From 5549 studies identified, 55 data sets (1489 healthy participants) met our inclusion criteria. Relative to neutral faces, we found extensive activation clusters by fearful faces in the right inferior temporal gyrus, right fusiform area, left putamen and amygdala, right parahippocampalgyrus and cerebellum; we found smaller activation clusters by angry faces in the right cerebellum and right middle temporal gyrus (MTG) and by disgusted faces in the left MTG. Happy and sad faces did not reach statistical significance. Clustering analyses showed similar activation patterns of fearful and angry faces; activation patterns of happy and sad faces showed the least correlation with other emotional faces. Emotional face processing was predominantly left-lateralized in the amygdala and anterior insula, and right-lateralized in the ventromedial prefrontal cortex.

LIMITATIONS

Reliance on discretized effect sizes based on peak coordinate location instead of statistical brain maps, and the varying level of statistical threshold reporting from original studies, could lead to underdetection of smaller clusters of activation.

CONCLUSION

Processing of emotional faces appeared to be oriented toward identifying threats on faces, from highest (i.e., angry or fearful faces) to lowest level (i.e., happy or sad faces), with a more complex lateralization pattern than previously theorized. Emotional faces may be processed in latent grouping but organized by threat content rather than emotional valence.

Examining the Dominant Presence of Brain Grey Matter in Autism During Functional Magnetic Resonance Imaging

Introduction

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with symptoms appearing from early childhood. Behavioral modifications, special education, and medicines are used to treat ASD; however, the effectiveness of the treatments depends on early diagnosis of the disorder. The primary approach in diagnosing ASD is based on clinical interviews and valid scales. Still, methods based on brain imaging could also be possible diagnostic biomarkers for ASD.

Methods

To identify the amount of information the functional magnetic resonance imaging (fMRI) reveals on ASD, we reviewed 292 task-based fMRI studies on ASD individuals. This study is part of a systematic review with the registration number CRD42017070975.

Results

We observed that face perception, language, attention, and social processing tasks were mainly studied in ASD. In addition, 73 brain regions, nearly 83% of brain grey matter, showed an altered activation between the ASD and normal individuals during these four tasks, either in a lower or a higher activation.

Conclusion

Using imaging methods, such as fMRI, to diagnose and predict ASD is a great objective; research similar to the present study could be the initial step.

Gray matter asymmetry atypical patterns in subgrouping minors with autism based on core symptoms

Abnormal gray matter (GM) asymmetry has been verified in autism spectrum disorder (ASD), which is characterized by high heterogeneity. ASD is distinguished by three core symptom domains. Previous neuroimaging studies have offered support for divergent neural substrates of different core symptom domains in ASD. However, no previous study has explored GM asymmetry alterations underlying different core symptom domains. This study sought to clarify atypical GM asymmetry patterns underlying three core symptom domains in ASD with a large sample of 230 minors with ASD (ages 7-18 years) and 274 matched TD controls from the Autism Brain Imaging Data Exchange I (ABIDE I) repository. To this end, the scores of the revised autism diagnostic interview (ADI-R) subscales were normalized for grouping ASD into three core-symptom-defined subgroups: social interaction (SI), verbal communication (VA), and restricted repetitive behaviors (RRB). We investigated core-symptom-related GM asymmetry alterations in ASD resulting from advanced voxel-based morphometry (VBM) by general linear models. We also examined the relationship between GM asymmetry and age and between GM asymmetry and symptom severity assessed by the Autism Diagnostic Observation Schedule (ADOS). We found unique GM asymmetry alterations underlying three core-symptom-defined subgroups in ASD: more rightward asymmetry in the thalamus for SI, less rightward asymmetry in the superior temporal gyrus, anterior cingulate and caudate for VA, and less rightward asymmetry in the middle and inferior frontal gyrus for RRB. Furthermore, the asymmetry indexes in the thalamus were negatively associated with ADOS_SOCIAL scores in the general ASD group. We also showed significant correlations between GM asymmetry and age in ASD and TD individuals. Our results support the theory that each core symptom domain of ASD may have independent etiological and neurobiological underpinnings, which is essential for the interpretation of heterogeneity and the future diagnosis and treatment of ASD.

Exaggerated amygdala activation to ambiguous facial expressions is a familial vulnerability factor for posttraumatic stress disorder

OBJECTIVE

Previous research has reported hyperresponsivity in the amygdala and hyporesponsivity in ventral portions of the medial prefrontal cortex to threat-related stimuli in posttraumatic stress disorder (PTSD). Whether such findings generalize to more ambiguous stimuli and whether such brain activation abnormalities reflect familial vulnerabilities, trauma-exposure, or acquired characteristics of PTSD remain unclear. In this study, we measured brain responses to emotionally ambiguous stimuli (i.e., surprised facial expressions) in identical twin pairs discordant for trauma exposure to elucidate the origin of brain activation abnormalities.

METHODS

Participants with PTSD (n = 12) and their trauma-unexposed identical cotwins (n = 12), as well as trauma-exposed participants without PTSD (n = 15) and their trauma-unexposed identical cotwins (n = 15), passively viewed surprised and neutral facial expressions during functional magnetic resonance imaging (fMRI). Afterward, participants labeled and rated each facial expression on valence and arousal.

RESULTS

Amygdala activation to Surprised and Neutral facial expressions (versus Fixation) was greater in the participants with PTSD and their trauma-unexposed identical cotwins without PTSD, compared to the control twin pairs. In contrast, medial frontal gyrus (MFG) activation to Surprised facial expressions (versus Fixation) was diminished in the PTSD group relative to the other three groups.

CONCLUSIONS

Amygdala hyperresponsivity to emotionally ambiguous facial expressions may be a familial vulnerability factor that increases the likelihood of developing PTSD after experiencing a traumatic event. In contrast, MFG hyporesponsivity may be an acquired characteristic of the disorder.

Attention to audiovisual speech does not facilitate language acquisition in infants with familial history of autism

BACKGROUND

Due to familial liability, siblings of children with ASD exhibit elevated risk for language delays. The processes contributing to language delays in this population remain unclear.

METHODS

Considering well-established links between attention to dynamic audiovisual cues inherent in a speaker's face and speech processing, we investigated if attention to a speaker's face and mouth differs in 12-month-old infants at high familial risk for ASD but without ASD diagnosis (hr-sib; n = 91) and in infants at low familial risk (lr-sib; n = 62) for ASD and whether attention at 12 months predicts language outcomes at 18 months.

RESULTS

At 12 months, hr-sib and lr-sib infants did not differ in attention to face (p = .14), mouth preference (p = .30), or in receptive and expressive language scores (p = .36, p = .33). At 18 months, the hr-sib infants had lower receptive (p = .01) but not expressive (p = .84) language scores than the lr-sib infants. In the lr-sib infants, greater attention to the face (p = .022) and a mouth preference (p = .025) contributed to better language outcomes at 18 months. In the hr-sib infants, neither attention to the face nor a mouth preference was associated with language outcomes at 18 months.

CONCLUSIONS

Unlike low-risk infants, high-risk infants do not appear to benefit from audiovisual prosodic and speech cues in the service of language acquisition despite intact attention to these cues. We propose that impaired processing of audiovisual cues may constitute the link between genetic risk factors and poor language outcomes observed across the autism risk spectrum and may represent a promising endophenotype in autism.

Decreased Empathy Response to Other's Pain in Parents of Children With Autism Spectrum Disorder

We aimed to investigate pain empathy ability and self-reported empathy among parents of children with autism spectrum disorder (ASD). Twenty-four parents of children with ASD and 26 parents of typically developing children completed the Empathy Quotient (EQ) self-report scale and responded to painful or neutral images during an empathy-for-pain paradigm test. Parents of children with ASD had lower EQ scores, lower accuracy, and longer reaction time (RT) for pain empathy task response (all p < 0.05) compared with controls. There was a negative relationship between cognitive empathy, social skills, total EQ scores, and RT of response in parents of children with ASD. Our findings indicate that self-reported empathy deficits and decreased empathy response to the sight of others' pain in parents of children with ASD are part of a broader autistic phenotype.

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

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

Differences in cortical processing of facial emotions in broader autism phenotype

Autism Spectrum Disorder (ASD) is a heterogeneous condition that affects face perception. Evidence shows that there are differences in face perception associated with the processing of low spatial frequency (LSF) and high spatial frequency (HSF) of visual stimuli between non-symptomatic relatives of individuals with autism (broader autism phenotype, BAP) and typically developing individuals. However, the neural mechanisms involved in these differences are not fully understood. Here we tested whether face-sensitive event related potentials could serve as neuronal markers of differential spatial frequency processing, and whether these potentials could differentiate non-symptomatic parents of children with autism (pASD) from parents of typically developing children (pTD). To this end, we performed electroencephalographic recordings of both groups of parents while they had to recognize emotions of face pictures composed of the same or different emotions (happiness or anger) presented in different spatial frequencies. We found no significant differences in the accuracy between groups but lower amplitude modulation in the Late Positive Potential activity in pASD. Source analysis showed a difference in the right posterior part of the superior temporal region that correlated with ASD symptomatology of the child. These results reveal differences in brain processing of recognition of facial emotion in BAP that could be a precursor of ASD.

Examining the relationship between measures of autistic traits and neural synchrony during movies in children with and without autism

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Neural synchrony during movie watching was measured in children with and without ASD.

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The ASD group had significantly less neural synchrony across the whole brain.

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The ASD group also had significantly less synchrony in the theory of mind network.

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Autistic traits did not predict neural synchrony in non-ASD children.

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These results suggest children with ASD process movies in a unique way.

Children who have been diagnosed with autism spectrum disorder (ASD) often show a marked deficit in measures of social cognition. In autistic adults, measures of social cognition have been shown to relate to differences in brain synchronization (as measured by fMRI) when individuals are processing naturalistic stimuli, such as movies. However, whether children who differ in their degree of autistic traits, with or without a diagnosis of ASD, differ in their neural responses to movies has not yet been investigated. In the current study, neural synchrony, measured using fMRI, was examined in three groups of children aged 7 to 12, who differed with respect to scores on a measure of autistic traits associated with social impairment and whether or not they had been diagnosed with ASD. While watching the movie ‘Despicable Me’, those diagnosed with ASD had significantly less neural synchrony in areas that have been previously shown to be associated with social cognition (e.g. areas related to ‘theory of mind’), and plot following (e.g. the lateral prefrontal cortex), than those who did not have an ASD diagnosis. In contrast, two groups who differed in their degree of autistic traits, but did not have a diagnosis of ASD, showed no significant differences in neural synchrony across the whole brain. These results shed some light on how autistic traits may contribute to an individual’s conscious experience of the world, and how, for children with ASD, that experience may differ markedly from that of those without ASD.

Core-Symptom-Defined Cortical Gyrification Differences in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a heterogeneous disease that is characterized by abnormalities in social communication and interaction as well as repetitive behaviors and restricted interests. Structural brain imaging has identified significant cortical folding alterations in ASD; however, relatively less known is whether the core symptoms are related to neuroanatomical differences. In this study, we aimed to explore core-symptom-anchored gyrification alterations and their developmental trajectories in ASD. We measured the cortical vertex-wise gyrification index (GI) in 321 patients with ASD (aged 7-39 years) and 350 typically developing (TD) subjects (aged 6-33 years) across 8 sites from the Autism Brain Imaging Data Exchange I (ABIDE I) repository and a longitudinal sample (14 ASD and 7 TD, aged 9-14 years in baseline and 12-18 years in follow-up) from ABIDE II. Compared with TD, the general ASD patients exhibited a mixed pattern of both hypo- and hyper- and different developmental trajectories of gyrification. By parsing the ASD patients into three subgroups based on the subscores of the Autism Diagnostic Interview-Revised (ADI-R) scale, we identified core-symptom-specific alterations in the reciprocal social interaction (RSI), communication abnormalities (CA), and restricted, repetitive, and stereotyped patterns of behavior (RRSB) subgroups. We also showed atypical gyrification patterns and developmental trajectories in the subgroups. Furthermore, we conducted a meta-analysis to locate the core-symptom-anchored brain regions (circuits). In summary, the current study shows that ASD is associated with abnormal cortical folding patterns. Core-symptom-based classification can find more subtle changes in gyrification. These results suggest that cortical folding pattern encodes changes in symptom dimensions, which promotes the understanding of neuroanatomical basis, and clinical utility in ASD.

Processing of pragmatic communication in ASD: a video-based brain imaging study

Social and pragmatic difficulties in autism spectrum disorder (ASD) are widely recognized, although their underlying neural level processing is not well understood. The aim of this study was to examine the activity of the brain network components linked to social and pragmatic understanding in order to reveal whether complex socio-pragmatic events evoke differences in brain activity between the ASD and control groups. Nineteen young adults (mean age 23.6 years) with ASD and 19 controls (mean age 22.7 years) were recruited for the study. The stimulus data consisted of video clips showing complex social events that demanded processing of pragmatic communication. In the analysis, the functional magnetic resonance imaging signal responses of the selected brain network components linked to social and pragmatic information processing were compared. Although the processing of the young adults with ASD was similar to that of the control group during the majority of the social scenes, differences between the groups were found in the activity of the social brain network components when the participants were observing situations with concurrent verbal and non-verbal communication events. The results suggest that the ASD group had challenges in processing concurrent multimodal cues in complex pragmatic communication situations.

The Mid-Fusiform Sulcus in Autism Spectrum Disorder: Establishing a Novel Anatomical Landmark Related to Face Processing

Despite decades of research, the brain basis of aberrant face processing in autism spectrum disorder (ASD) remains a topic of debate. The mid-fusiform sulcus (MFS), a minor feature of the ventral occipitotemporal cortex, provides new directions for studying face processing. The MFS closely aligns with face-selective cortical patches and other structural and functional divisions of the fusiform gyrus; however, it has received little attention in clinical populations. We collected structural MRI data from 54 individuals with ASD and 61 age-and-IQ-matched controls ages 8 to 40 years. The MFS was identified on cortical surface reconstructions via 4 trained raters and classified into known surface patterns. Mean MFS gray matter volume (GMV), cortical surface area (SA), cortical thickness (CT), and standard deviation of CT (CT SD) were extracted. Effects of diagnosis, age, and hemisphere on MFS surface presentation and morphometry were assessed via multinomial logistic regression and mixed effects general linear modeling, respectively. The MFS was reliably identified in 97% of hemispheres examined. Macroanatomical patterns and age-related decreases in MFS GMV and CT were similar between groups. CT SD was greater in the left hemisphere in ASD. Participants' ability to interpret emotions and mental states from facial features was significantly negatively correlated with MFS CT and CT SD. Overall, the MFS is a stable feature of the fusiform gyrus in ASD and CT related measures appear to be sensitive to diagnosis and behavior. These results can inform future investigations of face processing and structure-function relationships in populations with social deficits. LAY SUMMARY: A small structural feature of the brain related to seeing faces (the mid-fusiform sulcus; MFS) appears similar in autism spectrum disorder (ASD) and neurotypical development; however, the thickness of this structure on the left side of the brain is more variable in ASD. People who are better at judging mental states from another person's eyes tend to have thinner and less variable MFS. This feature may teach us more about face processing and how brain structure influences function in ASD.

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.

Social endophenotypes in autism spectrum disorder: A scoping review

Endophenotypes are measurable markers of genetic vulnerability to current or future disorder. Autism spectrum disorder (ASD) is well-suited to be examined within an endophenotype framework given past and current emphases on the broader autism phenotype and early detection. We conducted a scoping review to identify potential socially-related endophenotypes of ASD. We focused on paradigms related to sociality (e.g., theory of mind (TOM), social attention), which comprise most of this literature. We integrated findings from traditional behavioral paradigms with brain-based measures (e.g., electroencephalography, functional magnetic resonance imaging). Broadly, infant research regarding social attention and responsivity (Research Domain Criteria (RDoC) domain of affiliation) and attention to faces and voices (social communication) finds consistent abnormality in vulnerable infant siblings. Several additional paradigms that have shown differences in vulnerable infants and young children include animacy perception tasks (perception and understanding of others), measures of recognition and response to familiar faces (attachment), and joint attention and false-belief tasks (understanding mental states). Research areas such as alexithymia (the perception and understanding of self), empathic responding, and vocal prosody may hold interest; however, challenges in measurement across populations and age ranges is a limiting factor. Future work should address sex differences and age dependencies, specificity to ASD, and heterogeneous genetic pathways to disorder within samples individuals with ASD and relatives.

Social brain dysfunctionality in individuals with autism spectrum disorder and their first-degree relatives: An activation likelihood estimation meta-analysis

The social brain hypothesis is regarded as a powerful theory to understand social cognition. Individuals with autism spectrum disorder (ASD) have specific deficits in social and communicative behavior, but the exact relationship between these deficits and abnormalities in the social brain remains unclear. The high heritability of this disorder makes it important to focus on the first-degree relatives of those affected. Research focusing on genetically at-risk (yet healthy) relatives of patients with ASD is critical to the study of neuroimaging endophenotypes. We conducted a voxel-wise activation likelihood estimation (ALE) meta-analysis of 9 functional neuroimaging studies published during the period from 2006 to 2018. These studies included 200 individuals with ASD, 216 unaffected family members (UF), and 235 typical development controls (TD). The voxel-wise significance threshold was p < 0.01 (uncorrected p = 0.001).The ALE meta-analyses showed hyperactivation in the inferior frontal gyrus (IFG) and superior temporal gyrus (STG) among individuals with ASD and UF, compared with TD individuals. Group comparisons showed greater likelihood of hyperactivation in the amygdala for ASD, compared with UF and TD.

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.

The Animal in Me: Enhancing Emotion Recognition in Adolescents with Autism Using Animal Filters

People with autism are often characterized as having difficulties with theory of mind abilities such as emotion recognition. However, rather than being a pervasive deficit of ‘mindblindness,’ a number of studies suggests these difficulties vary by context, and when people with autism mindread non-human agents, such as animals or cartoons, these abilities improve. To replicate this effect, 15 adolescents with both autism and intellectual disability participated in a test of facial emotion recognition, with both human and animal faces. Participants performed significantly better on the animal version of the assessment compared to the human version, and human rather than animal scores were the strongest predictor of symptom severity. These results were shown to be primarily driven by improvement in recognition of the emotions happiness and anger in animal rather than human faces. Implications with regards to social motivation and theory of mind interventions are discussed.

Neural Correlates of Social Perception in Children with Autism: Local versus Global Preferences

The Weak Central Coherence account of autism spectrum disorders posits that individuals with ASD utilize a detail-oriented information processing bias. While this local bias is helpful in visual search tasks, ASD individuals falter in social cognition tasks where coherence is advantageous. The present study examined the neural correlates of Weak Central Coherence in ASD during visual and social processing. Fifteen ASD and sixteen typically developing children/adolescents completed a social/visual information processing task in an fMRI scanner. The stimuli consisted of human characters, composed of geometrical shapes, displaying different emotions. In the locally oriented Shape condition, participants indicated whether a given shape was present in a figure. In the Emotion condition, participants identified the emotion conveyed by the character in the figure at the global level. Whole-brain within- and between-group activation and seed-to-voxel functional connectivity analyses were conducted in SPM12 and the CONN toolbox. The ASD group was significantly faster in shape identification, but less accurate in emotion identification. The TD group showed significantly increased areas of activity over the ASD group in the Shape task in regions associated with executive control, such as the medial prefrontal cortex and middle frontal gyrus, suggesting increased interference from the global/social information. During the Emotion condition, the ASD group showed decreased connectivity between frontal and posterior regions and between body perception and motor networks, suggesting a possible difference in mirroring. The findings suggest that social cognitive factors, not visual processing biases, underlie the observed behavioral differences.

Visual and auditory emotion recognition problems as familial cross-disorder phenomenon in ASD and ADHD

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are frequently comorbid disorders. Emotion recognition problems are considered an important familial deficit in ASD, but this is unknown in ADHD. Very few studies have directly compared emotion recognition performance of youth with ASD and/or ADHD and of their unaffected siblings across age to quantify the contribution of emotion recognition problems to the ADHD phenotype. We therefore devised a study of 64 ASD+ADHD participants, 89 ASD-only participants, 111 ADHD-only participants, 122 unaffected ASD(+ADHD) siblings, 69 unaffected ADHD-only siblings and 220 controls aged 7-18 years, who had completed two tasks assessing auditory and visual emotion recognition. Factor analysis was used to detect underlying dimensions of emotion recognition capacity. Linear mixed models were used to compare performance across groups and to assess age effects. The factor-analysis revealed four factors separating speed and accuracy regarding visual and auditory emotion recognition. ASD+ADHD, ASD-only, and ADHD-only participants all performed worse than controls. ASD+ADHD, ASD-only, and ADHD-only participants did not differ in the severity of their emotion recognition problems. Both unaffected sibling groups performed intermediate between patients and controls. For ASD+ADHD and ADHD-only participants, group differences were more marked in adolescence than childhood, whereas in ASD participants this was not observed. We conclude that emotion recognition problems are a familial deficit in ADHD to a similar extent as in ASD. Emotion recognition problems specifically - and social cognition problems more generally - should be assessed in clinical practice for ADHD.

Anxiety and Attentional Bias to Threat in Children at Increased Familial Risk for Autism Spectrum Disorder

Anxiety and threat bias were examined in 6-8-year-old children at familial-risk for Autism Spectrum Disorder (ASD) and low-risk (LR, n = 37) controls. The high-risk (HR) group was divided into those who met diagnostic criteria for ASD (HR-ASD, n = 15) and those who did not (HR-non ASD, n = 24). The HR-ASD group had highest levels of parent-reported anxiety. The HR-non ASD group exhibited increased threat bias on a spatial-cueing task, while the HR-ASD group did not. Anxiety symptoms were associated with both threat bias and ASD severity. These findings suggest that the mechanisms underlying anxiety in HR siblings without ASD are similar to those in non-ASD populations. However, among children with ASD, hypersensitivity to threat may not underlie anxiety symptoms.

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.

Neuroanatomical and neurofunctional markers of social cognition in autism spectrum disorder

Social impairments in autism spectrum disorder (ASD), a hallmark feature of its diagnosis, may underlie specific neural signatures that can aid in differentiating between those with and without ASD. To assess common and consistent patterns of differences in brain responses underlying social cognition in ASD, this study applied an activation likelihood estimation (ALE) meta-analysis to results from 50 neuroimaging studies of social cognition in children and adults with ASD. In addition, the group ALE clusters of activation obtained from this was used as a social brain mask to perform surface-based cortical morphometry (SBM) in an empirical structural MRI dataset collected from 55 ASD and 60 typically developing (TD) control participants. Overall, the ALE meta-analysis revealed consistent differences in activation in the posterior superior temporal sulcus at the temporoparietal junction, middle frontal gyrus, fusiform face area (FFA), inferior frontal gyrus (IFG), amygdala, insula, and cingulate cortex between ASD and TD individuals. SBM analysis showed alterations in the thickness, volume, and surface area in individuals with ASD in STS, insula, and FFA. Increased cortical thickness was found in individuals with ASD, the IFG. The results of this study provide functional and anatomical bases of social cognition abnormalities in ASD by identifying common signatures from a large pool of neuroimaging studies. These findings provide new insights into the quest for a neuroimaging-based marker for ASD. Hum Brain Mapp 37:3957-3978, 2016. © 2016 Wiley Periodicals, Inc.

Sensory Responsiveness in Siblings of Children with Autism Spectrum Disorders

This study examined sensory responsiveness in unaffected siblings of children with autism spectrum disorder (ASD) and associations between sensory responsiveness and social severity. Sensory Profile Caregiver Questionnaires and Social Responsiveness Scales were completed by parents of 185 children between age 4 and 10.95 years. Significant differences were found between participants with ASD and controls, and between participants with ASD and unaffected siblings for all sensory quadrants and domains, but not between controls and unaffected siblings. Social responsiveness scores were significantly correlated with scores from most sensory profile categories. Sensory responsiveness as an endophenotype of ASD is not indicated from these findings; however, studies with larger numbers of unaffected siblings and controls are needed to confirm the null hypothesis.

Progress and roadblocks in the search for brain-based biomarkers of autism and attention-deficit/hyperactivity disorder

Children with neurodevelopmental disorders benefit most from early interventions and treatments. The development and validation of brain-based biomarkers to aid in objective diagnosis can facilitate this important clinical aim. The objective of this review is to provide an overview of current progress in the use of neuroimaging to identify brain-based biomarkers for autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), two prevalent neurodevelopmental disorders. We summarize empirical work that has laid the foundation for using neuroimaging to objectively quantify brain structure and function in ways that are beginning to be used in biomarker development, noting limitations of the data currently available. The most successful machine learning methods that have been developed and applied to date are discussed. Overall, there is increasing evidence that specific features (for example, functional connectivity, gray matter volume) of brain regions comprising the salience and default mode networks can be used to discriminate ASD from typical development. Brain regions contributing to successful discrimination of ADHD from typical development appear to be more widespread, however there is initial evidence that features derived from frontal and cerebellar regions are most informative for classification. The identification of brain-based biomarkers for ASD and ADHD could potentially assist in objective diagnosis, monitoring of treatment response and prediction of outcomes for children with these neurodevelopmental disorders. At present, however, the field has yet to identify reliable and reproducible biomarkers for these disorders, and must address issues related to clinical heterogeneity, methodological standardization and cross-site validation before further progress can be achieved.

A review of endophenotypes in schizophrenia and autism: The next phase for understanding genetic etiologies

Many psychiatric disorders are caused by multiple genes and multiple environmental factors, making the identification of specific genetic risk factors for these disorders difficult. Endophenotypes are behaviors or characteristics that are intermediate between the genotype and a phenotype of interest. Because they are more directly related to the gene action than is the endpoint disorder, they may be useful in the identification of specific genes related to psychiatric disorders and the classification of disorders or traits that share an underlying genetic etiology. We discuss genetic and endophenotype research on schizophrenia and autism spectrum disorder (ASD) in this review. Some of the psychophysiological endophenotypes that have been studied for schizophrenia include prepulse inhibition of the startle response, the antisaccadic task assessing frontal lobe function, inhibition of the P50 event-related potential (ERP), and other auditory ERP measures. Potential ASD endophenotypes include theory of mind, language skills (specifically, age at first spoken word and first spoken phrase), social skills, and certain brain functions, such as asynchronization of neural activity and brain responses to emotional faces. Because the link between genes and specific psychiatric disorders is difficult to determine, identification of endophenotypes is useful for beginning the search to identify specific genes that affect these disorders.

Exploring the heterogeneity of neural social indices for genetically distinct etiologies of autism

Background

Autism spectrum disorder (ASD) is a genetically and phenotypically heterogeneous disorder. Promising initiatives utilizing interdisciplinary characterization of ASD suggest phenotypic subtypes related to specific likely gene-disrupting mutations (LGDMs). However, the role of functionally associated LGDMs in the neural social phenotype is unknown.

Methods

In this study of 26 children with ASD (n = 13 with an LGDM) and 13 control children, we characterized patterns of mu attenuation and habituation as children watched videos containing social and nonsocial motions during electroencephalography acquisition.

Results

Diagnostic comparisons were consistent with prior work suggesting aberrant mu attenuation in ASD within the upper mu band (10–12 Hz), but typical patterns within the lower mu band (8–10 Hz). Preliminary exploration indicated distinct social sensitization patterns (i.e., increasing mu attenuation for social motion) for children with an LGDM that is primarily expressed during embryonic development. In contrast, children with an LGDM primarily expressed post-embryonic development exhibited stable typical patterns of lower mu attenuation. Neural social indices were associated with social responsiveness, but not cognition.

Conclusions

These findings suggest unique neurophysiological profiles for certain genetic etiologies of ASD, further clarifying possible genetic functional subtypes of ASD and providing insight into mechanisms for targeted treatment approaches.

Electronic supplementary material

The online version of this article (doi:10.1186/s11689-017-9199-4) contains supplementary material, which is available to authorized users.

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.

Cerebellar gray matter differentiates children with early language delay in autism

Early language delay (ELD) is one of the earliest indicators of autism spectrum disorder (ASD), and predicts later cognitive and behavioral outcomes. We aimed to determine the neural correlates of ELD in autism, and examine the relationships between gray matter (GM), age of first word/phrase, and core ASD symptoms. We used voxel-based morphometry to examine whole-brain differences in GM in 8-13 year old children with autism (n = 13 ELD; n = 22 non-ELD) and 35 age-matched typically developing (TD) children. Multiple regression analyses examined the relationships between GM, age of first word/phrase, and autism diagnostic observation schedule (ADOS) scores. Composite age of first word/phrase negatively correlated with GM throughout the cerebellum. Both ASD groups (ELD and non-ELD) had reduced GM in right cerebellar Crus I/II when compared to TD children. Left cerebellar Crus I/II was the only region in the brain that differentiated ELD and non-ELD children, with ELD children showing reduced GM relative to both non-ELD and TD groups. Group×score interactions converged in left Crus I/II, such that the non-ELD group showed poorer ADOS scores with increasing GM, whereas the ELD group showed poorer ADOS scores as GM decreased. Reduced GM in right cerebellar Crus I/I was related ASD diagnosis, while children with ELD showed additional reduced GM in left Crus I/II. These findings highlight the importance of specific cerebellar networks in both ASD and early language development, and suggest that bilateral disruption in cerebellar regions that interconnect with fronto-parietal networks could impact language acquisition in ASD. Autism Res 2016, 9: 1191-1204. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Default Mode Hypoconnectivity Underlies a Sex-Related Autism Spectrum

Background

Females and males differ significantly in the prevalence and presentation of autism spectrum conditions. One theory of this effect postulates that autistic traits lie on a sex-related continuum in the general population, and autism represents the extreme male end of this spectrum. This theory predicts that any feature of autism in males should 1) be present in autistic females, 2) differentiate between the sexes in the typical population, and 3) correlate with autistic traits. We tested these three predictions for default mode network (DMN) hypoconnectivity during the resting state, one of the most robustly found neurobiological differences in autism.

Methods

We analyzed a primary dataset of adolescents (N = 121, 12–18 years of age) containing a relatively large number of females and a replication multisite dataset including children, adolescents, and adults (N = 980, 6–58 years of age). We quantified the average connectivity between DMN regions and tested for group differences and correlation with behavioral performance using robust regression.

Results

We found significant differences in DMN intraconnectivity between female controls and females with autism (p = .001 in the primary dataset; p = .009 in the replication dataset), and between female controls and male controls (p = .036 in the primary dataset; p = .002 in the replication dataset). We also found a significant correlation between DMN intraconnectivity and performance on a mentalizing task (p = .001) in the primary dataset.

Conclusions

Collectively, these findings provide the first evidence for DMN hypoconnectivity as a behaviorally relevant neuroimaging phenotype of the sex-related spectrum of autistic traits, of which autism represents the extreme case.

The Autism-Spectrum Quotient in Siblings of People With Autism

This study measures the distribution of autistic traits, using the autism-spectrum quotient (AQ), in siblings of individuals with autism spectrum conditions (ASC). Total AQ scores, along with AQ subscales, were collected from child, adolescent and adult controls, siblings, and volunteers with ASC using one of the three age-appropriate versions of the instrument: the AQ (adult self-report), the AQ-adolescent and AQ-child (both parent-reports). We examined the effect of Group (case, sibling and control) and AQ version (adult, adolescent and adult) on total and subscale scores. In addition, we tested for sex differences in all groups and on all versions. We found that in male and female adults, AQ scores in siblings fell between cases and controls (cases > siblings > controls). In children and adolescents, female siblings also scored higher than control females (female cases > female siblings > female controls), but there was no difference between male siblings and controls (male cases > male siblings = male controls). An investigation of subscale scores revealed that male siblings only differed from controls on the "Communication" subscale (male cases > male siblings > male controls), while female siblings differed from controls on all subscales except "Imagination" (female cases > female siblings > female controls). This study confirms the broader autism phenotype in siblings, and reveals this is modulated by sex and AQ version. Autism Res 2017, 10: 289-297. © 2016 The Authors Autism Research published by Wiley Periodicals, Inc. on behalf of International Society for Autism Research.

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.

The promise of multi-omics and clinical data integration to identify and target personalized healthcare approaches in autism spectrum disorders

Complex diseases are caused by a combination of genetic and environmental factors, creating a difficult challenge for diagnosis and defining subtypes. This review article describes how distinct disease subtypes can be identified through integration and analysis of clinical and multi-omics data. A broad shift toward molecular subtyping of disease using genetic and omics data has yielded successful results in cancer and other complex diseases. To determine molecular subtypes, patients are first classified by applying clustering methods to different types of omics data, then these results are integrated with clinical data to characterize distinct disease subtypes. An example of this molecular-data-first approach is in research on Autism Spectrum Disorder (ASD), a spectrum of social communication disorders marked by tremendous etiological and phenotypic heterogeneity. In the case of ASD, omics data such as exome sequences and gene and protein expression data are combined with clinical data such as psychometric testing and imaging to enable subtype identification. Novel ASD subtypes have been proposed, such as CHD8, using this molecular subtyping approach. Broader use of molecular subtyping in complex disease research is impeded by data heterogeneity, diversity of standards, and ineffective analysis tools. The future of molecular subtyping for ASD and other complex diseases calls for an integrated resource to identify disease mechanisms, classify new patients, and inform effective treatment options. This in turn will empower and accelerate precision medicine and personalized healthcare.

Typical and atypical neurodevelopment for face specialization: an FMRI study

Individuals with autism spectrum disorder (ASD) and their relatives process faces differently from typically developed (TD) individuals. In an fMRI face-viewing task, TD and undiagnosed sibling (SIB) children (5-18 years) showed face specialization in the right amygdala and ventromedial prefrontal cortex, with left fusiform and right amygdala face specialization increasing with age in TD subjects. SIBs showed extensive antero-medial temporal lobe activation for faces that was not present in any other group, suggesting a potential compensatory mechanism. In ASD, face specialization was minimal but increased with age in the right fusiform and decreased with age in the left amygdala, suggesting atypical development of a frontal-amygdala-fusiform system which is strongly linked to detecting salience and processing facial information.

Aberrant function of frontoamygdala circuits in adolescents with previous verbal abuse experiences

Previous studies reported an association of depressive disorder and structural alteration of frontolimbic brain regions in subjects with emotional abuse experiences during childhood and adolescence. The results suggest that aberrant function of the frontolimbic circuit and its relation with psychiatric symptoms can be found in adolescents with preclinical status. We investigated functional changes of frontolimbic networks during implicit negative emotional face processing and their relationships with depressive symptoms in adolescents with previous verbal abuse experiences. We designed a gender discrimination task using emotional faces to induce an implicit level of emotional exposure, and was completed by 31 preclinical male adolescents during an fMRI scan. The right amygdala activity and its functional connectivity with the rostral anterior cingulate cortex (ACC) during implicit processing of negative emotional faces showed a significant relationship with previous verbal abuse experiences. The hierarchical regression analyses showed that their current depressive symptoms were associated with aberrant functional interaction between the right amygdala activity and right amygdala-rostral ACC connectivity. Our findings of verbal abuse-related functional changes in the right frontoamygdala circuit may be related to vulnerability to future mood disorder.

Identification of infants at high-risk for autism spectrum disorder using multiparameter multiscale white matter connectivity networks

Autism spectrum disorder (ASD) is a wide range of disabilities that cause life-long cognitive impairment and social, communication, and behavioral challenges. Early diagnosis and medical intervention are important for improving the life quality of autistic patients. However, in the current practice, diagnosis often has to be delayed until the behavioral symptoms become evident during childhood. In this study, we demonstrate the feasibility of using machine learning techniques for identifying high-risk ASD infants at as early as six months after birth. This is based on the observation that ASD-induced abnormalities in white matter (WM) tracts and whole-brain connectivity have already started to appear within 24 months after birth. In particular, we propose a novel multikernel support vector machine classification framework by using the connectivity features gathered from WM connectivity networks, which are generated via multiscale regions of interest (ROIs) and multiple diffusion statistics such as fractional anisotropy, mean diffusivity, and average fiber length. Our proposed framework achieves an accuracy of 76% and an area of 0.80 under the receiver operating characteristic curve (AUC), in comparison to the accuracy of 70% and the AUC of 70% provided by the best single-parameter single-scale network. The improvement in accuracy is mainly due to the complementary information provided by multiparameter multiscale networks. In addition, our framework also provides the potential imaging connectomic markers and an objective means for early ASD diagnosis.

Semi-Metric Topology of the Human Connectome: Sensitivity and Specificity to Autism and Major Depressive Disorder

Introduction

The human functional connectome is a graphical representation, consisting of nodes connected by edges, of the inter-relationships of blood oxygenation-level dependent (BOLD) time-series measured by MRI from regions encompassing the cerebral cortices and, often, the cerebellum. Semi-metric analysis of the weighted, undirected connectome distinguishes an edge as either direct (metric), such that there is no alternative path that is accumulatively stronger, or indirect (semi-metric), where one or more alternative paths exist that have greater strength than the direct edge. The sensitivity and specificity of this method of analysis is illustrated by two case-control analyses with independent, matched groups of adolescents with autism spectrum conditions (ASC) and major depressive disorder (MDD).

Results

Significance differences in the global percentage of semi-metric edges was observed in both groups, with increases in ASC and decreases in MDD relative to controls. Furthermore, MDD was associated with regional differences in left frontal and temporal lobes, the right limbic system and cerebellum. In contrast, ASC had a broadly increased percentage of semi-metric edges with a more generalised distribution of effects and some areas of reduction. In summary, MDD was characterised by localised, large reductions in the percentage of semi-metric edges, whilst ASC is characterised by more generalised, subtle increases. These differences were corroborated in greater detail by inspection of the semi-metric backbone for each group; that is, the sub-graph of semi-metric edges present in >90% of participants, and by nodal degree differences in the semi-metric connectome.

Conclusion

These encouraging results, in what we believe is the first application of semi-metric analysis to neuroimaging data, raise confidence in the methodology as potentially capable of detection and characterisation of a range of neurodevelopmental and psychiatric disorders.

Whole-brain functional hypoconnectivity as an endophenotype of autism in adolescents

Endophenotypes are heritable and quantifiable markers that may assist in the identification of the complex genetic underpinnings of psychiatric conditions. Here we examined global hypoconnectivity as an endophenotype of autism spectrum conditions (ASCs). We studied well-matched groups of adolescent males with autism, genetically-related siblings of individuals with autism, and typically-developing control participants. We parcellated the brain into 258 regions and used complex-network analysis to detect a robust hypoconnectivity endophenotype in our participant group. We observed that whole-brain functional connectivity was highest in controls, intermediate in siblings, and lowest in ASC, in task and rest conditions. We identified additional, local endophenotype effects in specific networks including the visual processing and default mode networks. Our analyses are the first to show that whole-brain functional hypoconnectivity is an endophenotype of autism in adolescence, and may thus underlie the heritable similarities seen in adolescents with ASC and their relatives.

Trait-level temporal lobe hypoactivation to social exclusion in unaffected siblings of children and adolescents with autism spectrum disorders

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Brain responses to social exclusion were measured in ASD unaffected siblings.

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Unaffected siblings show trait atypical activation in posterior temporal lobe.

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Biological vulnerability moderates relationship between IQ and brain responses.

Social exclusion elicits powerful feelings of negative affect associated with rejection. Additionally, experiencing social exclusion reliably recruits neural circuitry associated with emotion processing. Recent work has demonstrated abnormal neural responses to social exclusion in children and adolescents with autism spectrum disorders (ASD). However, it remains unknown to what extent these abnormalities are due to atypical social experiences versus genetic predispositions to atypical neural processing. To address this question, the current study investigated brain responses to social exclusion compared to a baseline condition of fair play in unaffected siblings of youth with ASD using functional magnetic resonance imaging. We identified common deviations between unaffected siblings and ASD probands that might represent trait-level abnormalities in processing Social Exclusion vs. Fair Play, specifically in the right anterior temporoparietal junction extending into posterior superior temporal sulcus. Thus, hypoactivation to Social Exclusion vs. Fair Play in this region may represent a shared genetic vulnerability to developing autism. In addition, we present evidence supporting the idea that one's status as an unaffected sibling moderates the relationship between IQ and neural activation to Social Exclusion vs. Fair Play in anterior cingulate cortex. These results are discussed in the context of previous literature on neural endophenotypes of autism.

The Cambridge Mindreading Face-Voice Battery for Children (CAM-C): complex emotion recognition in children with and without autism spectrum conditions

Background

Difficulties in recognizing emotions and mental states are central characteristics of autism spectrum conditions (ASC). However, emotion recognition (ER) studies have focused mostly on recognition of the six ‘basic’ emotions, usually using still pictures of faces.

Methods

This study describes a new battery of tasks for testing recognition of nine complex emotions and mental states from video clips of faces and from voice recordings taken from the Mindreading DVD. This battery (the Cambridge Mindreading Face-Voice Battery for Children or CAM-C) was given to 30 high-functioning children with ASC, aged 8 to 11, and to 25 matched controls.

Results

The ASC group scored significantly lower than controls on complex ER from faces and voices. In particular, participants with ASC had difficulty with six out of nine complex emotions. Age was positively correlated with all task scores, and verbal IQ was correlated with scores in the voice task. CAM-C scores were negatively correlated with parent-reported level of autism spectrum symptoms.

Conclusions

Children with ASC show deficits in recognition of complex emotions and mental states from both facial and vocal expressions. The CAM-C may be a useful test for endophenotypic studies of ASC and is one of the first to use dynamic stimuli as an assay to reveal the ER profile in ASC. It complements the adult version of the CAM Face-Voice Battery, thus providing opportunities for developmental assessment of social cognition in autism.

Multimodal neuroimaging based classification of autism spectrum disorder using anatomical, neurochemical, and white matter correlates

Neuroimaging techniques, such as fMRI, structural MRI, diffusion tensor imaging (DTI), and proton magnetic resonance spectroscopy (1H-MRS) have uncovered evidence for widespread functional and anatomical brain abnormalities in autism spectrum disorder (ASD) suggesting it to be a system-wide neural systems disorder. Nevertheless, most previous studies have focused on examining one index of neuropathology through a single neuroimaging modality, and seldom using multiple modalities to examine the same cohort of individuals. The current study aims to bring together multiple brain imaging modalities (structural MRI, DTI, and 1H-MRS) to investigate the neural architecture in the same set of individuals (19 high-functioning adults with ASD and 18 typically developing (TD) peers). Morphometry analysis revealed increased cortical thickness in ASD participants, relative to typical controls, across the left cingulate, left pars opercularis of the inferior frontal gyrus, left inferior temporal cortex, and right precuneus, and reduced cortical thickness in right cuneus and right precentral gyrus. ASD adults also had reduced fractional anisotropy (FA) and increased radial diffusivity (RD) for two clusters on the forceps minor of the corpus callosum, revealed by DTI analyses. 1H-MRS results showed a reduction in the N-acetylaspartate/Creatine ratio in dorsal anterior cingulate cortex (dACC) in ASD participants. A decision tree classification analysis across the three modalities resulted in classification accuracy of 91.9% with FA, RD, and cortical thickness as key predictors. Examining the same cohort of adults with ASD and their TD peers, this study found alterations in cortical thickness, white matter (WM) connectivity, and neurochemical concentration in ASD. These findings underscore the potential for multimodal imaging to better inform on the neural characteristics most relevant to the disorder.

Developmental white matter microstructure in autism phenotype and corresponding endophenotype during adolescence

During adolescence, white matter microstructure undergoes an important stage of development. It is hypothesized that the alterations of brain connectivity that have a key role in autism spectrum conditions (ASCs) may interact with the development of white matter microstructure. This interaction may be present beyond the phenotype of autism in siblings of individuals with ASC, who are 10 to 20 times more likely to develop certain forms of ASC. We use diffusion tensor imaging to examine how white matter microstructure measurements correlate with age in typically developing individuals, and how this correlation differs in n=43 adolescents with ASC and their n=38 siblings. Correlations observed in n=40 typically developing individuals match developmental changes noted in previous longitudinal studies. In comparison, individuals with ASC display weaker negative correlation between age and mean diffusivity in a broad area centred in the right superior longitudinal fasciculus. These differences may be caused either by increased heterogeneity in ASC or by temporal alterations in the group's developmental pattern. Siblings of individuals with ASC also show diminished negative correlation between age and one component of mean diffusivity-second diffusion eigenvalue-in the right superior longitudinal fasciculus. As the observed differences match for location and correlation directionality in our comparison of typically developing individuals to those with ASC and their siblings, we propose that these alterations constitute a part of the endophenotype of autism.

Association of autism tendency and hemodynamic changes in the prefrontal cortex during facial expression stimuli measured by multi-channel near-infrared spectroscopy

AIM

The aim of this study is to examine the hemodynamic changes induced by the cognitive process of facial expression by using multi-channel near-infrared spectroscopy in healthy subjects with varying degrees of autism tendency.

METHODS

Subjects were 38 volunteers, 20 men and 18 women. Autism tendency was measured by the Autism Spectrum Quotient. The hemodynamic changes in the prefrontal cortex were measured by 24-channel near-infrared spectroscopy system, while subjects were asked to judge their own emotional response to standardized pictures of eight kinds of facial expressions on a computer screen.

RESULTS

There were significant negative correlations between Autism Spectrum Quotient scores and accuracy of fearful expression recognition as well as increases in the concentration of oxygenated hemoglobin in response to four kinds of emotional faces (fear, contempt, sadness and disgust).

CONCLUSION

Our findings suggest that the greater tendency to autism that subjects have, the more difficulty they have in recognizing a fearful expression and the less hemodynamic change in the prefrontal cortex they show in response to negative facial expressions.

Meta-Analysis of Gene Expression in Autism Spectrum Disorder

Autism spectrum disorders (ASD) are clinically heterogeneous and biologically complex. In general it remains unclear, what biological factors lead to changes in the brains of autistic individuals. A considerable number of transcriptome analyses have been performed in attempts to address this question, but their findings lack a clear consensus. As a result, each of these individual studies has not led to any significant advance in understanding the autistic phenotype as a whole. Here, we report a meta-analysis of more than 1000 microarrays across twelve independent studies on expression changes in ASD compared to unaffected individuals, in both blood and brain tissues. We identified a number of known and novel genes that are consistently differentially expressed across three studies of the brain (71 samples in total). A subset of the highly ranked genes is suggestive of effects on mitochondrial function. In blood, consistent changes were more difficult to identify, despite individual studies tending to exhibit larger effects than the brain studies. Our results are the strongest evidence to date of a common transcriptome signature in the brains of individuals with ASD.

Social-cognitive, physiological, and neural mechanisms underlying emotion regulation impairments: understanding anxiety in autism spectrum disorder

Anxiety is one of the most common clinical problems among children, adolescents, and adults with autism spectrum disorder (ASD), yet we know little about its etiology in the context of ASD. We posit that emotion regulation (ER) impairments are a risk factor for anxiety in ASD. Specifically, we propose that one reason why anxiety disorders are so frequently comorbid with ASD is because ER impairments are ubiquitous to ASD, stemming from socio-cognitive, physiological, and neurological processes related to impaired cognitive control, regulatory processes, and arousal. In this review, we offer a developmental model of how ER impairments may arise in ASD, and when (moderating influences) and how (meditational mechanisms) they result in anxiety.

'Reading the Mind in the Eyes': an fMRI study of adolescents with autism and their siblings

BACKGROUND

Mentalizing deficits are a hallmark of the autism spectrum condition (ASC) and a potential endophenotype for atypical social cognition in ASC. Differences in performance and neural activation on the 'Reading the Mind in the Eyes' task (the Eyes task) have been identified in individuals with ASC in previous studies.

METHOD

Performance on the Eyes task along with the associated neural activation was examined in adolescents with ASC (n = 50), their unaffected siblings (n = 40) and typically developing controls (n = 40). Based on prior literature that males and females with ASC display different cognitive and associated neural characteristics, analyses were stratified by sex. Three strategies were applied to test for endophenotypes at the level of neural activation: (1) identifying and locating conjunctions of ASC-control and sibling-control differences; (2) examining whether the sibling group is comparable to the ASC or intermediate between the ASC and control groups; and (3) examining spatial overlaps between ASC-control and sibling-control differences across multiple thresholds.

RESULTS

Impaired behavioural performance on the Eyes task was observed in males with ASC compared to controls, but only at trend level in females; and no difference in performance was identified between sibling and same-sex control groups in both sexes. Neural activation showed a substantial endophenotype effect in the female groups but this was only modest in the male groups.

CONCLUSIONS

Behavioural impairment on complex emotion recognition associated with mental state attribution is a phenotypic, rather than an endophenotypic, marker of ASC. However, the neural response during the Eyes task is a potential endophenotypic marker for ASC, particularly in females.