Hypoconnectivity of insular resting-state networks in adolescents with Autism Spectrum Disorder

Insular functional connectivity in autistic and non-autistic development

BACKGROUND

There is evidence for altered interoceptive processing in individuals diagnosed with autism, compared to non-autistic individuals. At a neural level, functional and structural connectivity of interoceptive cortices may differ in autism, though developmental patterns of these differences are unclear as well as how these patterns may vary by subregion within the insular cortex. To better understand the roles of autism, age, and subregion in interoceptive connectivity patterns, we used a cross-sectional approach to examine interoceptive functional connectivity across individuals spanning a wide age range.

METHODS

N=59 autistic individuals (ages 7-54) and N=71 non-autistic individuals (ages 7-51) completed a resting-state functional magnetic resonance imaging scan. From these scans, we analyzed seed-based functional connectivity of insula subregions (posterior, middle, and anterior) by hemisphere. We analyzed associations with age, group, and interoceptive self-reported experiences, as measured in a subset of individuals who completed the Body Perception Questionnaire.

RESULTS

We found that with age, primary interoceptive cortex showed decreased functional coupling with subcortical regions such as the thalamus and increased coupling with multimodal parietal regions. Functional connectivity within key interoceptive areas was decreased in those with increased reported body awareness. Differences between the autistic and non-autistic groups were minimal, with a single finding of heightened connectivity in autism between left posterior insula and lateral occipital cortex.

CONCLUSIONS

These findings shed light on potential developmental shifts in how interoceptive processing is balanced between lower-order and higher-order areas. Further, they provide background for how autistic patterns of interoceptive processing may be considered relative to age.

Dynamic functional adaptations during touch observation in autism: connectivity strength is linked to attitudes towards social touch and social responsiveness

BACKGROUND

Autistic adults experience differences in social interactions involving physical contact. Brain imaging studies suggest that these differences may be related to atypical brain responses to social-affective cues, affecting both the experience of receiving touch and observing it in others. However, it remains unclear whether these atypical responses are limited to specific brain regions or represent broader alterations in brain connectivity. The current study investigated how the functional network architecture is modulated during touch observation associated with autism and explored the extent to which changes in this architecture are associated with individual differences in social touch preferences and social responsiveness.

METHODS

By integrating generalized psychophysiological interaction (gPPI) analysis with independent component analysis (ICA), the current study analyzed existing fMRI datasets, in which 21 autistic and 21 non-autistic male adults viewed videos of social and nonsocial touch while undergoing MRI scans.

RESULTS

A gPPI analysis of regions of interest revealed that autistic adults exhibited increased connectivity between sensory and social brain regions. The strength of some of these connections was positively associated with a higher preference for social touch and greater social responsiveness, suggesting neural compensatory mechanisms that may help autistic adults better understand the meaning of touch. At the level of large-scale brain networks extracted using ICA, atypical connectivity was predominantly observed between the sensorimotor network and other networks involved in social-emotional processing. Increased connectivity was observed in the sensorimotor network during nonsocial touch, suggesting that embodied simulation, the process by which individuals internally simulate touch experience of others in this context, may be more engaged when observing human-object interactions than during human-to-human touch.

LIMITATIONS

This study focused on a specific subgroup of 21 autistic male adults with minimal support needs. Future research would benefit from including a more diverse autistic sample.

CONCLUSIONS

This study reveals atypical context-dependent modulation of functional brain architecture associated with autism during touch observation. Neural compensatory mechanisms in autistic individuals who enjoy social touch and show higher social responsiveness may function as adaptive social responses. However, these compensations may be limited to specific brain regions, rather than occurring at the level of large-scale brain networks.

Salience Network in Autism: preliminary results on functional connectivity analysis in resting state

The literature suggests that alterations in functional connectivity (FC) of the Salience Network (SN) may contribute to the manifestation of some clinical features of Autism Spectrum Disorder (ASD). The SN plays a key role in integrating external sensory information with internal emotional and bodily information. An atypical FC of this network could explain some symptomatic features of ASD such as difficulties in self-awareness and emotion processing and provide new insights into the neurobiological basis of autism. Using the Autism Brain Imaging Data Exchange II we investigated the resting-state FC of core regions of SN and its association with autism symptomatology in 29 individuals with ASD compared with 29 typically developing (TD) individuals. In ASD compared to TD individuals, seed-based connectivity analysis showed a reduced FC between the rostral prefrontal cortex and left cerebellum and an increased FC between the right supramarginal gyrus and the regions of the middle temporal gyrus and angular gyrus. Finally, we found that the clinical features of ASD are mainly associated with an atypical FC of the anterior insula and the involvement of dysfunctional mechanisms for emotional and social information processing. These findings expand the knowledge about the differences in the FC of SN between ASD and TD, highlighting atypical FC between structures that play key roles in social cognition and complex cognitive processes. Such anomalies could explain difficulties in processing salient stimuli, especially those of a socio-affective nature, with an impact on emotional and behavioral regulation.

Relationship Between Interoception and Autistic Traits: A Resting-State Functional Connectivity Study

Interoception, the sense of the physiological condition of our body, is impaired in individuals with autism spectrum disorders. Evidence suggests that subclinical autistic traits are mild manifestations of autistic symptoms, present in the general population. We examined the resting-state functional connectivity (rsFC) associating with interoception and autistic traits in 62 healthy young adults. Autistic traits correlated negatively with the rsFC between the lateral ventral anterior insula and anterior cingulate cortex. Interoceptive accuracy and sensibility correlated positively with the rsFC between interoceptive brain networks and the cerebellum, supplementary motor area, and visual regions. The results suggest that a negative relationship between interoception and autistic traits is largely accounted for by both self-report measures and decreased rsFC amongst the interoceptive brain network.

Social intelligence mediates the protective role of resting-state brain activity in the social cognition network against social anxiety

Background

Social intelligence refers to an important psychosocial skill set encompassing an array of abilities, including effective self-expression, understanding of social contexts, and acting wisely in social interactions. While there is ample evidence of its importance in various mental health outcomes, particularly social anxiety, little is known on the brain correlates underlying social intelligence and how it can mitigate social anxiety.

Objective

This research aims to investigate the functional neural markers of social intelligence and their relations to social anxiety.

Methods

Data of resting-state functional magnetic resonance imaging and behavioral measures were collected from 231 normal students aged 16 to 20 years (48% male). Whole-brain voxel-wise correlation analysis was conducted to detect the functional brain clusters related to social intelligence. Correlation and mediation analyses explored the potential role of social intelligence in the linkage of resting-state brain activities to social anxiety.

Results

Social intelligence was correlated with neural activities (assessed as the fractional amplitude of low-frequency fluctuations, fALFF) among two key brain clusters in the social cognition networks: negatively correlated in left superior frontal gyrus (SFG) and positively correlated in right middle temporal gyrus. Further, the left SFG fALFF was positively correlated with social anxiety; brain-personality-symptom analysis revealed that this relationship was mediated by social intelligence.

Conclusion

These results indicate that resting-state activities in the social cognition networks might influence a person's social anxiety via social intelligence: lower left SFG activity → higher social intelligence → lower social anxiety. These may have implication for developing neurobehavioral interventions to mitigate social anxiety.

Neurochemical differences in core regions of the autistic brain: a multivoxel 1H-MRS study in children

Autism spectrum disorder (ASD) is a neurodevelopmental condition which compromises various cognitive and behavioural domains. The understanding of the pathophysiology and molecular neurobiology of ASD is still an open critical research question. Here, we aimed to address ASD neurochemistry in the same time point at key regions that have been associated with its pathophysiology: the insula, hippocampus, putamen and thalamus. We conducted a multivoxel proton magnetic resonance spectroscopy (1H-MRS) study to non-invasively estimate the concentrations of total choline (GPC + PCh, tCho), total N-acetyl-aspartate (NAA + NAAG, tNAA) and Glx (Glu + Gln), presenting the results as ratios to total creatine while investigating replication for ratios to total choline as a secondary analysis. Twenty-two male children aged between 10 and 18 years diagnosed with ASD (none with intellectual disability, in spite of the expected lower IQ) and 22 age- and gender-matched typically developing (TD) controls were included. Aspartate ratios were significantly lower in the insula (tNAA/tCr: p = 0.010; tNAA/tCho: p = 0.012) and putamen (tNAA/tCr: p = 0.015) of ASD individuals in comparison with TD controls. The Glx ratios were significantly higher in the hippocampus of the ASD group (Glx/tCr: p = 0.027; Glx/tCho: p = 0.011). Differences in tNAA and Glx indices suggest that these metabolites might be neurochemical markers of region-specific atypical metabolism in ASD children, with a potential contribution for future advances in clinical monitoring and treatment.

Relationship between abnormal intrinsic functional connectivity of subcortices and autism symptoms in high-functioning adults with autism spectrum disorder

PURPOSE

This study explores subcortices and their intrinsic functional connectivity (iFC) in autism spectrum disorder (ASD) adults and investigates their relationship with clinical severity.

METHODS

Resting-state functional magnetic resonance imaging (rs-fMRI) data were acquired from 74 ASD patients, and 63 gender and age-matched typically developing (TD) adults. Independent component analysis (ICA) was conducted to evaluate subcortical patterns of basal ganglia (BG) and thalamus. These two brain areas were treated as regions of interest to further calculate whole-brain FC. In addition, we employed multivariate machine learning to identify subcortices-based FC brain patterns and clinical scores to classify ASD adults from those TD subjects.

RESULTS

In ASD individuals, autism diagnostic observation schedule (ADOS) was negatively correlated with the BG network. Similarly, social responsiveness scale (SRS) was negatively correlated with the thalamus network. The BG-based iFC analysis revealed adults with ASD versus TD had lower FC, and its FC with the right medial temporal lobe (MTL), was positively correlated with SRS and ADOS separately. ASD could be predicted with a balanced accuracy of around 60.0 % using brain patterns and 84.7 % using clinical variables.

CONCLUSION

Our results revealed the abnormal subcortical iFC may be related to autism symptoms.

Connectivity differences between inferior frontal gyrus and mentalizing network in autism as compared to developmental coordination disorder and non-autistic youth

Prior studies have compared neural connectivity during mentalizing tasks in autism (ASD) to non-autistic individuals and found reduced connectivity between the inferior frontal gyrus (IFG) and mentalizing regions. However, given that the IFG is involved in motor processing, and about 80% of autistic individuals have motor-related difficulties, it is necessary to explore if these differences are specific to ASD or instead similar across other developmental motor disorders, such as developmental coordination disorder (DCD). Participants (29 ASD, 20 DCD, 31 typically developing [TD]; ages 8-17) completed a mentalizing task in the fMRI scanner, where they were asked to think about why someone was performing an action. Results indicated that the ASD group, as compared to both TD and DCD groups, showed significant functional connectivity differences when mentalizing about other's actions. The left IFG seed revealed ASD connectivity differences with the: bilateral temporoparietal junction (TPJ), left insular cortex, and bilateral dorsolateral prefrontal cortex (DLPFC). Connectivity differences using the right IFG seed revealed ASD differences in the: left insula, and right DLPFC. These results indicate that connectivity differences between the IFG, mentalizing regions, emotion and motor processing regions are specific to ASD and not a result of potentially co-occurring motor differences.

Disrupted functional connectivity of the primary auditory cortex in autism

Autism Spectrum Disorder (ASD) has been found to influence hearing and sensory integration, while brain functional connectivity in ASD has been repeatedly shown to be atypical. However, functional connectivity of the auditory cortex in ASD has not been well studied. In the current study, we used resting-state functional magnetic resonance imaging data, provided by the Autism Brain Imaging Data Exchange (ABIDE), to examine functional connectivity of the primary auditory cortex in ASD. The study subjects included 68 individuals with ASD and 77 individuals without ASD. In the primary dataset, the ASD group showed lesser functional connectivity between the auditory cortex and four regions: the medial occipital cortex, primary motor cortex, insular cortex, and Wernicke's area. In the replication dataset (44 individuals with ASD and 39 individuals without ASD), reduced connectivity to the medial occipital cortex and primary motor cortex was replicated among these four regions, which have previously been shown to be influenced by ASD. Thus, the reduced functional connectivity to these indicated regions may partly explain deficient sensory integration associated with ASD.

The Brain-Gut-Microbiome System: Pathways and Implications for Autism Spectrum Disorder

Gastrointestinal dysfunction is one of the most prevalent physiological symptoms of autism spectrum disorder (ASD). A growing body of largely preclinical research suggests that dysbiotic gut microbiota may modulate brain function and social behavior, yet little is known about the mechanisms that underlie these relationships and how they may influence the pathogenesis or severity of ASD. While various genetic and environmental risk factors have been implicated in ASD, this review aims to provide an overview of studies elucidating the mechanisms by which gut microbiota, associated metabolites, and the brain interact to influence behavior and ASD development, in at least a subgroup of individuals with gastrointestinal problems. Specifically, we review the brain-gut-microbiome system and discuss findings from current animal and human studies as they relate to social-behavioral and neurological impairments in ASD, microbiota-targeted therapies (i.e., probiotics, fecal microbiota transplantation) in ASD, and how microbiota may influence the brain at molecular, structural, and functional levels, with a particular interest in social and emotion-related brain networks. A deeper understanding of microbiome-brain-behavior interactions has the potential to inform new therapies aimed at modulating this system and alleviating both behavioral and physiological symptomatology in individuals with ASD.

Individuals with Autistic Traits Exhibit Heightened Alexithymia But Intact Interoceptive-Exteroceptive Sensory Integration

Interoceptive accuracy has been widely measured using the Heartbeat Tracking Test (HTT). We devised the novel paradigm of Interoception-Exteroception Synchronicity Judgement (IESJ) task to assess participants' interoceptive accuracy, exteroceptive accuracy, and the balancing score which reflected the ability to allocate attentions between interoceptive and exteroceptive signals. This study administered the behavioural paradigms of the HTT and the IESJ as well as other self-report scales to 119 typically-developing youths. Individuals with lower autistic traits (n = 30) showed comparable interoceptive accuracy, exteroceptive accuracy, and balancing scores as their higher autistic traits counterparts (n = 33). Taken together, the high autistic traits subgroup exhibited higher levels of alexithymia but not empathy or interoception than the low autistic traits subgroup.

Multidimensional Interoception and Autistic Traits Across life Stages: Evidence From a Novel Eye-tracking Task

Interoception is believed to underlie socio-cognitive functions which are often impaired in individuals with autism spectrum disorders (ASD). In this study, Experiment 1 examined in a sample of 114 neurotypical college students the associations among autistic traits, alexithymia, and interoceptive accuracy (IA), which was assessed by a novel paradigm "Eye-tracking Interoceptive Accuracy Task (EIAT). In Experiment 2, EIAT and the Autism Spectrum Quotient were administered to 52 preschool children, 50 adolescents, and 50 adults. Experiment 1 supported the association between autistic traits and alexithymia, but failed to support their association with multidimensional interoception. Experiment 2 strongly supported the association between age and IA. We conclude that cardiac IA differs between neurotypical age groups, but shows limited relationship with autistic traits.

Common variants of the autism-associated CNTNAP2 gene contribute to the modulatory effect of social function mediated by temporal cortex

Autistic traits are highly heritable and characterized by social deficits. Common genetic variants of the autism-related CNTNAP2 gene have been linked with social impairments, but the neural substrates are poorly understood. In the present study, we investigated the genetic effect of common variants of CNTNAP2 (rs2710102 and rs7794745) on gray matter volume and its association with social performance among 442 healthy participants. Our results showed that individuals with rs2710102 GG homozygotes had smaller left superior temporal gyrus (STG)/insular volume than A-allele carriers (AA and AG), while individuals with rs7794745 TT and AT showed smaller right parahippocampal, right STG/insular, and left inferior parietal lobule (IPL) cortex volume than those with rs7794745 AA. Smaller volume of the STG/insular and parahippocampal cortex was associated with poorer social performance. An indirect effect of CNTNAP2 rs7794745 and rs2710102 genotype on the social performance was mediated by the STG/insular cortex and parahippocampal cortex volume. These findings provided insight into the genetic effect of CNTNAP2 variants on social behavior, which may be moderated by the temporal cortex.

Perceived friendship and binge drinking in young adults: A study of the Human Connectome Project data

BACKGROUND

Peer influences figure prominently in young adult binge drinking. Women have trended to show a level of alcohol use on par with men during the last decades. It would be of interest to investigate the neural processes of social cognition that may underlie binge drinking and the potential sex differences.

METHODS

Here, we examined the data of the Human Connectome Project where we identified a total of 175 binge drinkers (125 men) and 285 non-binge drinkers (97 men) performing a social cognition task during brain imaging. We analyzed the imaging data with published routines and evaluated the results at a corrected threshold.

RESULTS

Both male and female binge relative to non-binge drinkers showed higher perceived friendship. Binge relative to non-binge drinkers demonstrated diminished activations in the anterior medial orbitofrontal cortex (amOFC) during perception of social vs. random interaction, with a more prominent effect size in women. Further, whole-brain regression identified activity of the right posterior insula (rPI) in negative correlation with perceived friendship score in non-binge drinking women. Post-hoc analyses showed significant correlation of rPI activity with perceived friendship, amOFC activity, and a summary measure of alcohol use severity identified by principal component analysis, across all subjects. Mediation and path analysis demonstrated a significant model: amOFC activity → rPI activity → perceived friendship → severity of alcohol use.

CONCLUSIONS

These findings support peer influences on binge drinking and suggest neural correlates that may relate altered social cognitive processing to alcohol misuse in young adults.

Differences in subcortico-cortical interactions identified from connectome and microcircuit models in autism

The pathophysiology of autism has been suggested to involve a combination of both macroscale connectome miswiring and microcircuit anomalies. Here, we combine connectome-wide manifold learning with biophysical simulation models to understand associations between global network perturbations and microcircuit dysfunctions in autism. We studied neuroimaging and phenotypic data in 47 individuals with autism and 37 typically developing controls obtained from the Autism Brain Imaging Data Exchange initiative. Our analysis establishes significant differences in structural connectome organization in individuals with autism relative to controls, with strong between-group effects in low-level somatosensory regions and moderate effects in high-level association cortices. Computational models reveal that the degree of macroscale anomalies is related to atypical increases of recurrent excitation/inhibition, as well as subcortical inputs into cortical microcircuits, especially in sensory and motor areas. Transcriptomic association analysis based on postmortem datasets identifies genes expressed in cortical and thalamic areas from childhood to young adulthood. Finally, supervised machine learning finds that the macroscale perturbations are associated with symptom severity scores on the Autism Diagnostic Observation Schedule. Together, our analyses suggest that atypical subcortico-cortical interactions are associated with both microcircuit and macroscale connectome differences in autism.

Electroencephalographic Correlate of Mexican Spanish Emotional Speech Processing in Autism Spectrum Disorder: To a Social Story and Robot-Based Intervention

Socio-emotional impairments are key symptoms of Autism Spectrum Disorders. This work proposes to analyze the neuronal activity related to the discrimination of emotional prosodies in autistic children (aged 9 to 11-year-old) as follows. Firstly, a database for single words uttered in Mexican Spanish by males, females, and children will be created. Then, optimal acoustic features for emotion characterization will be extracted, followed of a cubic kernel function Support Vector Machine (SVM) in order to validate the speech corpus. As a result, human-specific acoustic properties of emotional voice signals will be identified. Secondly, those identified acoustic properties will be modified to synthesize the recorded human emotional voices. Thirdly, both human and synthesized utterances will be used to study the electroencephalographic correlate of affective prosody processing in typically developed and autistic children. Finally, and on the basis of the outcomes, synthesized voice-enhanced environments will be created to develop an intervention based on social-robot and Social Story^TM for autistic children to improve affective prosodies discrimination. This protocol has been registered at BioMed Central under the following number: ISRCTN18117434.

Altered patterns of brain dynamics linked with body mass index in youth with autism

Children with autism spectrum disorder (ASD) have higher rates of overweight and obesity (OWOB) compared with typically developing (TD) children. Brain functional connectivity differences have been shown in both ASD and OWOB. However, only one study to date has examined ASD and OWOB concurrently, so little is known regarding the neural mechanisms associated with the higher prevalence of OWOB and its behavioral impacts in ASD. We investigated co-activation patterns (CAPs) of brain regions identified by independent component analysis in 129 children and adolescents between 6 and 18 years of age (n = 68 ASD). We examined the interaction between body mass index (BMI) and diagnosis in predicting dynamic brain metrics (dwell time, DT; frequency of occurrence, and transitions between states) as well as dimensional brain-behavior relationships. The relationship between BMI and brain dynamics was moderated by diagnosis (ASD, TD), particularly among the frequency of CAP 4, characterized by co-activation of lateral frontoparietal, temporal, and frontal networks. This pattern was negatively associated with parent-reported inhibition skills. Children with ASD had shorter CAP 1, characterized by co-activation of the subcortical, temporal, sensorimotor, and frontal networks, and CAP 4 DTs compared with TD children. CAP 1 DT was negatively associated with cognitive flexibility, inhibition, social functioning, and BMI. Cognitive flexibility moderated the relationship between BMI and brain dynamics in the visual network. Our findings provide novel evidence of neural mechanisms associated with OWOB in children with ASD. Further, poorer cognitive flexibility may result in increased vulnerability for children with ASD and co-occurring OWOB. LAY SUMMARY: Obesity is a societal epidemic and is common in autism, however, little is known about the neural mechanisms associated with the higher rates of obesity in autism. Here, we find unique patterns of brain dynamics associated with obesity in autism that were not observed in typically developing children. Further, the relationship between body mass index and brain dynamics depended on cognitive flexibility. These findings suggest that individuals with autism may be more vulnerable to the effects of obesity on brain function. Autism Res 2021, 14: 873-886. © 2021 International Society for Autism Research, Wiley Periodicals LLC.

Underconnectivity Between Visual and Salience Networks and Links With Sensory Abnormalities in Autism Spectrum Disorders

OBJECTIVE

The anterior insular cortex (AI), which is a part of the salience network, is critically involved in visual awareness, multisensory perception, and social and emotional processing, among other functions. In children and adolescents with autism spectrum disorders (ASDs), evidence has suggested aberrant functional connectivity (FC) of AI compared with typically developing peers. While recent studies have primarily focused on the functional connections between salience and social networks, much less is known about connectivity between AI and primary sensory regions, including visual areas, and how these patterns may be linked to autism symptomatology.

METHOD

The current investigation implemented functional magnetic resonance imaging to examine resting-state FC patterns of salience and visual networks in children and adolescents with ASDs compared with typically developing controls, and to relate them to behavioral measures.

RESULTS

Functional underconnectivity was found in the ASD group between left AI and bilateral visual cortices. Moreover, in an ASD subgroup with more atypical visual sensory profiles, FC was positively correlated with abnormal social motivational responsivity.

CONCLUSION

Findings of reduced FC between salience and visual networks in ASDs potentially indicate deficient selection of salient information. Moreover, in children and adolescents with ASDs who show strongly atypical visual sensory profiles, connectivity at seemingly more neurotypical levels may be paradoxically associated with greater impairment of social motivation.