Structural alterations of the social brain: a comparison between schizophrenia and autism

Uncovering convergence and divergence between autism and schizophrenia using genomic tools and patients' neurons

Autism spectrum disorders (ASDs) are highly heritable and result in abnormal repetitive behaviors and impairment in communication and cognitive skills. Previous studies have focused on the genetic correlation between ASDs and other neuropsychiatric disorders, but an in-depth understanding of the correlation to other disorders is required. We conducted an extensive meta-analysis of common variants identified in ASDs by genome-wide association studies (GWAS) and compared it to the consensus genes and single nucleotide polymorphisms (SNPs) of Schizophrenia (SCZ). We found approximately 75% of the GWAS genes that are associated with ASD are also associated with SCZ. We further investigated the cellular phenotypes of neurons derived from induced pluripotent stem cell (iPSC) models in ASD and SCZ. Our findings revealed that ASD and SCZ neurons initially follow divergent developmental trajectories compared to control neurons. However, despite these early diametrical differences, both ASD and SCZ neurons ultimately display similar deficits in synaptic activity as they mature. This significant genetic overlap between ASD and SCZ, coupled with the convergence towards similar synaptic deficits, highlights the intricate interplay of genetic and developmental factors in shaping the shared underlying mechanisms of these complex neurodevelopmental and neuropsychiatric disorders.

Disentangling the role of gray matter volume and concentration in autism spectrum disorder: A meta-analytic investigation of 25 years of voxel-based morphometry research

Despite over two decades of neuroimaging research, a unanimous definition of the pattern of structural variation associated with autism spectrum disorder (ASD) has yet to be found. One potential impeding issue could be the sometimes ambiguous use of measurements of variations in gray matter volume (GMV) or gray matter concentration (GMC). In fact, while both can be calculated using voxel-based morphometry analysis, these may reflect different underlying pathological mechanisms. We conducted a coordinate-based meta-analysis, keeping apart GMV and GMC studies of subjects with ASD. Results showed distinct and non-overlapping patterns for the two measures. GMV decreases were evident in the cerebellum, while GMC decreases were mainly found in the temporal and frontal regions. GMV increases were found in the parietal, temporal, and frontal brain regions, while GMC increases were observed in the anterior cingulate cortex and middle frontal gyrus. Age-stratified analyses suggested that such variations are dynamic across the ASD lifespan. The present findings emphasize the importance of considering GMV and GMC as distinct yet synergistic indices in autism research.

Aggravation of cognitive impairments in the valproic acid-induced animal model of autism in BALB/c mice infected with Toxoplasma gondii

PURPOSE

Toxoplasmosis is a disease caused by infection with a type of coccidial protozoan parasite called Toxoplasma gondii. The relationship between toxoplasmosis and cognitive disorders in neurodegenerative diseases has been proven. There is also evidence that children born to Toxoplasma-infected mothers are more likely to develop autism.

METHODS

In the present study, Toxoplasma-infected pregnant BALB/c mice were given valproic acid to induce autism in their male offspring, and their social behaviors, learning, and memory were examined. Chronic toxoplasmosis was established in BALB/c mice by intraperitoneal injection of cyst form of T. gondii. To induce autism, 600 mg/kg of valproic acid was injected intraperitoneally into mice on the 12.5th day of pregnancy. The behavioral experiments, such as social interaction, novel object recognition, and passive avoidance tasks, were performed on male offspring at 50 days.

RESULTS

Toxoplasma and valproic acid during the embryonic period caused social communication deficits and disrupted recognition memory and avoidance memory in offspring. Our findings showed that administering valproic acid to Toxoplasma-infected mothers exacerbates cognitive disorders in their offspring.

Effects of music on cognitive behavioral impairments in both sex of adult rats exposed prenatally to valproic acid

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairment in reciprocal social interactions, deficits in communication, and restrictive and repetitive behaviors and interests. In previous studies, music has been identified as an intervention therapy for children with ASD.

OBJECTIVES

The present study evaluated the effects of music on cognitive behavioral impairments in both sexes of adult rats exposed prenatally to Valproic acid.

METHODS

For induction of autism, pregnant female rats were pretreated with either saline or VPA (600 mg/kg.i.p.) at gestational day (GD) 12.5. Male and female offspring were divided into Saline.Non-Music, VPA.Non-Music, Saline.Music, and VPA.Music groups. The adult rats in the music groups were exposed to Mozart's piano sonata K.448 for 30 days (4 h/day), from postnatal day (PND) 60 to 90. Social interaction and Morris water maze (MWM) tasks were tested at PND 90.

RESULTS

Our results revealed that prenatal exposure to VPA decreased sociability and social memory performance in both sexes of adult rats. Moreover, prenatal exposure to VPA created learning and memory impairments in both sexes of adult rats in the MWM task. Music intervention improved sociability in both sexes of VPA-exposed rats and social memory in both sexes of VPA-exposed rats, especially in females. Furthermore, our results revealed that music ameliorated learning impairments in VPA-exposed female rats in the MWM task. In addition, music improved spatial memory impairments in VPA-exposed rats of both sexes, especially in females, which needs more investigation in molecular and histological fields in future studies.

CONCLUSION

Music intervention improved sociability and social memory in adult VPA-exposed rats, especially in female animals. Furthermore, music improved memory impairments in VPA-exposed rats of both sexes. It seems that music had a better influence on female rats. However, future studies need more investigations in molecular and histological fields.

White and gray matter correlates of theory of mind in autism: a voxel-based morphometry study

Autism spectrum disorder (ASD) is characterized by difficulties in theory of mind (ToM) and social communication. Studying structural and functional correlates of ToM in the brain and how autistic and nonautistic groups differ in terms of these correlates can help with diagnosis and understanding the biological mechanisms of ASD. In this study, we investigated white matter volume (WMV) and gray matter volume (GMV) differences between matching autistic and nonautistic samples, and how these structural features relate to age and ToM skills, indexed by the Reading the Mind in the Eyes (RMIE) measure. The results showed widespread GMV and WMV differences between the two groups in regions crucial for social processes. The autistic group did not express the typically observed negative GMV and positive WMV correlations with age at the same level as the nonautistic group, pointing to abnormalities in developmental structural changes. In addition, we found differences between the two groups in how GMV relates to ToM, particularly in the left frontal regions, and how WMV relates to ToM, mostly in the cingulate and corpus callosum. Finally, GMV in the left insula, a region that is part of the salience network, was found to be crucial in distinguishing ToM performance between the two groups.

Immersive and maladaptive daydreaming and divergent thinking in autism spectrum disorders

Little is known about the internal mental experiences of individuals with ASD. While some research suggests a limited capacity for imagination, other studies show heightened interest in fantasy and unique forms of creative thinking in ASD. This study explored daydreaming experiences in adults with ASD, with a focus on immersive daydreaming and its relation to divergent thinking abilities. Individuals with and without a diagnosis of ASD were surveyed on their daydreaming habits and completed a divergent thinking task. Experiences of immersive daydreaming were identified in 42% of adults with ASD and were related to broad ASD traits in those without a diagnosis of ASD. However, ASD diagnosis was unrelated to originality of divergent thinking, which was negatively associated with immersive daydreaming. Moreover, daydreaming experiences in ASD were diverse. A more nuanced understanding of the mental experiences in ASD may assist in the development of interventions and support for this population.

Music alleviates cognitive impairments in an animal model of autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by core symptoms including impairment in social communication and restrictive and repetitive behaviors and interests. Music has emerged in the past decade as an intervention therapy for children with ASD. The aim of the present study was to evaluate the effects of music on cognition impairments in the valproic acid (VPA) rat model of autism. The VPA was administered for animal modeling of autism on embryonic day 12.5 (E12.5) (600 mg/kg). Male and female pups were sub divided into four main groups (Saline.Non-music, VPA.Non-music, Saline.Music, and VPA.Music). The rats in the music groups were exposed to Mozart's piano sonata K.448 for 30 days (4 h/day), from postnatal day (PND) 21 to 50. Autistic-like behaviors were tested using a social interaction, the Morris water maze (MWM), and a passive avoidance tasks at the end of the PND 50. Our results demonstrated that VPA-exposed rat pups had significantly lower sociability and social memory performance compared with the saline-exposed rats in both sexes. VPA-exposed rat pups exhibited learning and memory impairments in the MWM and passive avoidance tasks. Our results demonstrated that music improved sociability in VPA-exposed rats, especially in males. Furthermore, our findings revealed that music improved learning impairments in VPA-exposed male rats in MWM task. In addition, music improved spatial memory impairments in VPA-exposed rats of both sexes. We also found that music improved passive avoidance memory impairments in VPA-exposed rats of both sexes, especially in females. More investigation in future studies are needed.

Evaluation of brain structure abnormalities in children with autism spectrum disorder (ASD) using structural magnetic resonance imaging

Background

Autism spectrum disorder (ASD) is a group of developmental disorders of the nervous system. Since the core cause of many of the symptoms of autism spectrum disorder is due to changes in the structure of the brain, the importance of examining the structural abnormalities of the brain in these disorder becomes apparent. The aim of this study is evaluation of brain structure abnormalities in children with autism spectrum disorder (ASD) using structural magnetic resonance imaging (sMRI). sMRI images of 26 autistic and 26 Healthy control subjects in the range of 5–10 years are selected from the ABIDE database. For a better assessment of structural abnormalities, the surface and volume features are extracted together from this images. Then, the extracted features from both groups were compared with the sample t test and the features with significant differences between the two groups were identified.

Results

The results of volume-based features indicate an increase in total brain volume and white matter and a change in white and gray matter volume in brain regions of Hammers atlas in the autism group. In addition, the results of surface-based features indicate an increase in mean and standard deviation of cerebral cortex thickness and changes in cerebral cortex thickness, sulcus depth, surface complexity and gyrification index in the brain regions of the Desikan–Killany cortical atlas.

Conclusions

Identifying structurally abnormal areas of the brain and examining their relationship to the clinical features of Autism Spectrum Disorder can pave the way for the correct and early detection of this disorder using structural magnetic resonance imaging. It is also possible to design treatment for autistic people based on the abnormal areas of the brain, and to see the effectiveness of the treatment using imaging.

Examining Associations Between Amygdala Volumes and Anxiety Symptoms in Autism Spectrum Disorder

BACKGROUND

Anxiety is one of the most common co-occurring conditions in people with autism spectrum disorder. The amygdala has been identified as being associated with anxiety in populations with and without autism, yet associations in autism were based on relatively small or developmentally constrained samples, leaving questions as to whether these results hold at different developmental ages and in a larger, more robust sample.

METHODS

Structural neuroimaging and parent report of anxiety symptoms of children ages 5-13 years with (n = 123) and without (n = 171) a diagnosis of autism were collected from the University of Maryland and three sites from the Autism Brain Imaging Data Exchange. Standardized residuals for bilateral amygdala volumes were computed adjusting for site, hemispheric volumes, and covariates (age, sex, Full Scale IQ).

RESULTS

Clinically significant anxiety symptoms did not differentiate amygdala volumes between groups (i.e., autism and anxiety, autism without anxiety, without autism or anxiety). No significant association between left or right amygdala volumes and anxiety scores was observed among the sample of individuals with autism. Meta-analytic and Bayes factor estimations provided additional support for the null hypothesis. Age, sex, and autism severity did not moderate associations between anxiety and amygdala volumes.

CONCLUSIONS

No relation between amygdala volumes and anxiety symptoms in children with autism was observed in the largest sample to investigate this question. We discuss directions for future research to determine whether additional factors including age or method of assessment may contribute to this lack of association.

Histamine H3 receptor antagonist, ciproxifan, alleviates cognition and synaptic plasticity alterations in a valproic acid-induced animal model of autism

RATIONALE

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and cognitive behaviors. Histamine H3 receptor (H3R) antagonists are considered as therapeutic factors for treating cognitive impairments.

OBJECTIVES

The aim of the present study was to evaluate the effects of the H3R antagonist, ciproxifan (CPX), on cognition impairment especially, spatial learning memory, and synaptic plasticity in the CA1 region of the hippocampus in autistic rats.

METHODS

Pregnant rats were injected with either valproic acid (VPA) (600 mg/kg, i.p.) or saline on an embryonic day 12.5 (E12.5). The effects of the H3R antagonist, ciproxifan (CPX) (1, 3 mg/kg, i.p.), were investigated on learning and memory in VPA-exposed rat pups and saline-exposed rat pups using Morris water maze (MWM) and social interaction tasks. The H2R antagonist, famotidine (FAM) (10, 20, 40 mg/kg, i.p.), was used to determine whether brain histaminergic neurotransmission exerted its procognitive effects through the H2R. In addition, synaptic reinforcement was evaluated by in vivo field potential recording.

RESULTS

The results showed that VPA-exposed rat pups had significantly lower sociability and social memory performance compared to the saline rats. VPA-exposed rat pups exhibited learning and memory impairments in the MWM task. In addition, VPA caused suppression of long-term potentiation (LTP) in the CA1 area of the hippocampus. Our results demonstrated that CPX 3 mg/kg improved VPA-induced cognitive impairments and FAM 20 mg/kg attenuated cognitive behaviors as well as electrophysiological properties.

CONCLUSIONS

CPX 3 mg/kg improved VPA-induced impairments of LTP as well as learning and memory deficits through H2R.

Participation of Hippocampal 5-HT5A, 5-HT6 and 5-HT7 Serotonin Receptors on the Consolidation of Social Recognition Memory

Social recognition is the ability of animals to identify and recognize a conspecific. The consolidation of social stimuli in long-term memory is crucial for the establishment and maintenance of social groups, reproduction and species survival. Despite its importance, little is known about the circuitry and molecular mechanisms involved in the social recognition memory (SRM). Serotonin (5-hydroxytryptamine, 5-HT) is acknowledged as a major neuromodulator, which plays a key role in learning and memory. Focusing on the more recently described 5-HT receptors, we investigated in the CA1 region of the dorsal hippocampus the participation of 5-HT_5A, 5-HT₆ and 5-HT₇ receptors in the consolidation of SRM. Male Wistar rats cannulated in CA1 were subjected to a social discrimination task. In the sample phase the animals were exposed to a juvenile conspecific for 1 h. Immediately after, they received different pharmacological treatments. Twenty-four hours later, they were submitted to a 5 min retention test in the presence of the previously presented juvenile (familiar) and a novel juvenile. The animals that received infusions of 5-HT_5A receptor antagonist SB-699551 (10 µg/µL), 5-HT₆ receptor agonist WAY-208466 (0.63 µg/µL) or 5-HT₇ receptor agonist AS-19 (5 µg/µL) intra-CA1 were unable to recognize the familiar juvenile. This effect was blocked by the coinfusion of WAY-208466 plus 5-HT₆ receptor antagonist SB-271046 (10 µg/µL) or AS-19 plus 5-HT₇ receptor antagonist SB-269970 (5 µg/µL). The present study helps to clarify the neurobiological functions of the 5-HT receptors more recently described and extends our knowledge about mechanisms underlying the SRM.

A meta-analytic investigation of grey matter differences in anorexia nervosa and autism spectrum disorder

Recent research reports Anorexia Nervosa (AN) to be highly dependent upon neurobiological function. Some behaviours, particularly concerning food selectivity are found in populations with both Autism Spectrum Disorder (ASD) and AN, and there is a proportionally elevated number of anorexic patients exhibiting symptoms of ASD. We performed a systematic review of structural MRI literature with the aim of identifying common structural neural correlates common to both AN and ASD. Across 46 ASD publications, a meta‐analysis of volumetric differences between ASD and healthy controls revealed no consistently affected brain regions. Meta‐analysis of 23 AN publications revealed increased volume within the orbitofrontal cortex and medial temporal lobe, and adult‐only AN literature revealed differences within the genu of the anterior cingulate cortex. The changes are consistent with alterations in flexible reward‐related learning and episodic memory reported in neuropsychological studies. There was no structural overlap between ASD and AN. Findings suggest no consistent neuroanatomical abnormality associated with ASD, and evidence is lacking to suggest that reported behavioural similarities between those with AN and ASD are due to neuroanatomical structural similarities.

Findings related to neuroanatomical structure in AN/ASD demonstrate overlap and require revisiting.

Meta‐analytic findings show structural increase/decrease versus healthy controls (LPFC/MTL/OFC) in AN, but no clusters found in ASD.

The neuroanatomy associated with ASD is inconsistent, but findings in AN reflect condition‐related impairment in executive function and sociocognitive behaviours.

Subcortical Brain Morphometry Differences between Adults with Autism Spectrum Disorder and Schizophrenia

Autism spectrum disorder (ASD) and schizophrenia (SZ) are neuropsychiatric disorders that overlap in symptoms associated with social-cognitive impairment. Subcortical structures play a significant role in cognitive and social-emotional behaviors and their abnormalities are associated with neuropsychiatric conditions. This exploratory study utilized ABIDE II/COBRE MRI and corresponding phenotypic datasets to compare subcortical volumes of adults with ASD (n = 29), SZ (n = 51) and age and gender matched neurotypicals (NT). We examined the association between subcortical volumes and select behavioral measures to determine whether core symptomatology of disorders could be explained by subcortical association patterns. We observed volume differences in ASD (viz., left pallidum, left thalamus, left accumbens, right amygdala) but not in SZ compared to their respective NT controls, reflecting morphometric changes specific to one of the disorder groups. However, left hippocampus and amygdala volumes were implicated in both disorders. A disorder-specific negative correlation (r = −0.39, p = 0.038) was found between left-amygdala and scores on the Social Responsiveness Scale (SRS) Social-Cognition in ASD, and a positive association (r = 0.29, p = 0.039) between full scale IQ (FIQ) and right caudate in SZ. Significant correlations between behavior measures and subcortical volumes were observed in NT groups (ASD-NT range; r = −0.53 to −0.52, p = 0.002 to 0.004, SZ-NT range; r = −0.41 to −0.32, p = 0.007 to 0.021) that were non-significant in the disorder groups. The overlap of subcortical volumes implicated in ASD and SZ may reflect common neurological mechanisms. Furthermore, the difference in correlation patterns between disorder and NT groups may suggest dysfunctional connectivity with cascading effects unique to each disorder and a potential role for IQ in mediating behavior and brain circuits.

Brain mRNA Expression Associated with Cortical Volume Alterations in Autism Spectrum Disorder

Numerous studies report abnormal cerebral cortex volume (CCV) in autism spectrum disorder (ASD); however, genes related to CCV abnormalities in ASD remain largely unknown. Here, we identify genes associated with CCV alterations in ASD by performing spatial correlations between the gene expression of 6 donated brains and neuroimaging data from 1,404 ASD patients and 1,499 controls. Based on spatial correlations between gene expression and CCV differences from two independent meta-analyses and between gene expression and individual CCV distributions of 404 patients and 496 controls, we identify 417 genes associated with both CCV differences and individual CCV distributions. These genes are enriched for genetic association signals and genes downregulated in the ASD post-mortem brain. The expression patterns of these genes are correlated with brain activation patterns of language-related neural processes frequently impaired in ASD. These findings highlight a model whereby genetic risk impacts gene expression (downregulated), which leads to CCV alterations in ASD.

Social Cognitive Performance in Schizophrenia Spectrum Disorders Compared With Autism Spectrum Disorder: A Systematic Review, Meta-analysis, and Meta-regression

IMPORTANCE

Schizophrenia spectrum disorders (SSDs) and autism spectrum disorder (ASD) both feature social cognitive deficits; however, these disorders historically have been examined separately using a range of tests and subdomain focus and at different time points in the life span. Moving beyond diagnostic categories and characterizing social cognitive deficits can enhance understanding of shared pathways across these disorders.

OBJECTIVE

To investigate how deficits in social cognitive domains diverge or overlap between SSDs and ASD based on the extant literature.

DATA SOURCES

Literature searches were conducted in MEDLINE, PsycInfo, Embase, and Web of Science from database inception until July 26, 2020.

STUDY SELECTION

Original research articles were selected that reported performance-based measures of social cognition in both SSDs and ASD samples. Selected articles also had to be published in English and use International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, DSM-IV, or more recent diagnostic criteria.

DATA EXTRACTION AND SYNTHESIS

This systematic review and meta-analysis was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses and Meta-analysis of Observational Studies in Epidemiology reporting guidelines, including data extraction and quality assessment using a modified version of the Newcastle-Ottawa Scale. Data were pooled using a random-effects model.

MAIN OUTCOMES AND MEASURES

Effect sizes were calculated as Hedges g (SSDs vs ASD). The primary outcomes were performance on emotion processing tasks, theory of mind (ToM) tasks, and the Reading the Mind in the Eyes Test (RMET) in SSDs compared with ASD. Meta-regressions were performed for age difference, publication year, quality assessment scores, and antipsychotic medication use.

RESULTS

Of the 4175 screened articles, 36 studies directly comparing social cognitive performance in individuals with SSDs vs ASD were included in the qualitative analysis (n = 1212 for SSDs groups and n = 1109 for ASD groups), and 33 studies were included in the quantitative analyses (n = 1113 for SSDs groups and n = 1015 for ASD groups). Most study participants were male (number of studies [k] = 36, 72% [878 of 1212] in SSDs groups and 82% [907 of 1109] in ASD groups), and age (k = 35) was older in SSDs groups (mean [SD], 28.4 [9.5] years) than in ASD groups (mean [SD], 23.3 [7.6] years). Included studies highlighted the prevalence of small, male-predominant samples and a paucity of cross-disorder clinical measures. The meta-analyses revealed no statistically significant differences between SSDs and ASD on emotion processing measures (k = 15; g = 0.12 [95% CI, -0.07 to 0.30]; P = .21; I2 = 51.0%; 1 outlier excluded), ToM measures (k = 17; g = -0.01 [95% CI, -0.21 to 0.19]; P = .92; I2 = 56.5%; 1 outlier excluded), or the RMET (k = 13; g = 0.25 [95% CI, -0.04 to 0.53]; P = .10; I2 = 75.3%). However, SSDs vs ASD performance differences between studies were statistically significantly heterogeneous, which was only minimally explained by potential moderators.

CONCLUSIONS AND RELEVANCE

In this analysis, similar levels of social cognitive impairment were present, on average, in individuals with SSDs and ASD. Cross-disorder studies of social cognition, including larger samples, consensus batteries, and consistent reporting of measures, as well as data across multiple levels of analysis, are needed to help identify subgroups within and across disorders that may be more homogeneous in etiology and treatment response.

Visual-Tactile Spatial Multisensory Interaction in Adults With Autism and Schizophrenia

Background: Individuals with autism spectrum disorder (ASD) and schizophrenia (SZ) exhibit multisensory processing difficulties and social impairments, with growing evidence that the former contributes to the latter. However, this work has largely reported on separate cohorts, introducing method variance as a barrier to drawing broad conclusions across studies. Further, very few studies have addressed touch, resulting in sparse knowledge about how these two clinical groups may integrate somatic information with other senses. Methods: In this study, we compared adults with ASD (n = 29), SZ (n = 24), and typical developmental histories (TD, n = 37) on two tasks requiring visual-tactile spatial multisensory processing. In the first task (crossmodal congruency), participants judged the location of a tactile stimulus in the presence or absence of simultaneous visual input that was either spatially congruent or incongruent, with poorer performance for incongruence an index of spatial multisensory interaction. In the second task, participants reacted to touch in the presence or absence of dynamic visual stimuli that appeared to approach or recede from the body. Within a certain radius around the body, defined as peripersonal space (PPS), an approaching visual or auditory stimulus reliably speeds reaction times (RT) to touch; outside of this radius, in extrapersonal space (EPS), there is no multisensory effect. PPS can be defined both by its size (radius) and slope (sharpness of the PPS-EPS boundary). Clinical measures were administered to explore relations with visual-tactile processing. Results: Neither clinical group differed from controls on the crossmodal congruency task. The ASD group had significantly smaller and more sharply-defined PPSs compared to the other two groups. Small PPS size was related to social symptom severity across groups, but was largely driven by the TD group, without significant effects in either clinical group. Conclusions: These results suggest that: (1) spatially static visual-tactile facilitation is intact in adults with ASD and SZ, (2) spatially dynamic visual-tactile facilitation impacting perception of the body boundary is affected in ASD but not SZ, and (3) body boundary perception is related to social-emotional function, but not in a way that maps on to clinical status.

Social Cognition in a Research Domain Criteria Perspective: A Bridge Between Schizophrenia and Autism Spectra Disorders

Schizophrenia and autism spectra disorders are currently conceptualized as distinct clinical categories. However, the relationship between these two nosological entities has been revisited in recent years due to the evidence that they share some important clinical and neurobiological features, putting into question the nature and the extent of their commonalities and differences. In this respect, some core symptoms that are present in both disorders, such as social cognitive deficits, could be a primary target of investigation. This review briefly summarizes the commonalities and overlapping features between schizophrenia and autism spectra disorders in social cognitive functions, considering this construct in a Research Domain Criteria perspective. The clinical manifestation of deficits in social cognition are similar in schizophrenia spectrum disorders and autism spectrum disorders, and brain areas that appear to be altered in relation to these impairments are largely shared; however, the results of various studies suggest that, in some cases, the qualitative nature of these alterations may be different in the two spectra. Moreover, relevant differences could be present at the level of brain networks and connections. More research is required in this field, regarding molecular and genetic aspects of both spectra, to better define the neurobiological mechanisms involved in social cognition deficits, with the objective of developing specific and targeted treatments.

Comparative meta-analyses of brain structural and functional abnormalities during cognitive control in attention-deficit/hyperactivity disorder and autism spectrum disorder

BACKGROUND

People with attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) have abnormalities in frontal, temporal, parietal and striato-thalamic networks. It is unclear to what extent these abnormalities are distinctive or shared. This comparative meta-analysis aimed to identify the most consistent disorder-differentiating and shared structural and functional abnormalities.

METHODS

Systematic literature search was conducted for whole-brain voxel-based morphometry (VBM) and functional magnetic resonance imaging (fMRI) studies of cognitive control comparing people with ASD or ADHD with typically developing controls. Regional gray matter volume (GMV) and fMRI abnormalities during cognitive control were compared in the overall sample and in age-, sex- and IQ-matched subgroups with seed-based d mapping meta-analytic methods.

RESULTS

Eighty-six independent VBM (1533 ADHD and 1295 controls; 1445 ASD and 1477 controls) and 60 fMRI datasets (1001 ADHD and 1004 controls; 335 ASD and 353 controls) were identified. The VBM meta-analyses revealed ADHD-differentiating decreased ventromedial orbitofrontal (z = 2.22, p < 0.0001) but ASD-differentiating increased bilateral temporal and right dorsolateral prefrontal GMV (zs ⩾ 1.64, ps ⩽ 0.002). The fMRI meta-analyses of cognitive control revealed ASD-differentiating medial prefrontal underactivation but overactivation in bilateral ventrolateral prefrontal cortices and precuneus (zs ⩾ 1.04, ps ⩽ 0.003). During motor response inhibition specifically, ADHD relative to ASD showed right inferior fronto-striatal underactivation (zs ⩾ 1.14, ps ⩽ 0.003) but shared right anterior insula underactivation.

CONCLUSIONS

People with ADHD and ASD have mostly distinct structural abnormalities, with enlarged fronto-temporal GMV in ASD and reduced orbitofrontal GMV in ADHD; and mostly distinct functional abnormalities, which were more pronounced in ASD.

Cerebellar-Cortical Connectivity Is Linked to Social Cognition Trans-Diagnostically

Background: Psychotic disorders are characterized by impairment in social cognitive processing, which is associated with poorer community functioning. However, the neural mechanisms of social impairment in psychosis remain unclear. Social impairment is a hallmark of other psychiatric illnesses as well, including autism spectrum disorders (ASD), and the nature and degree of social cognitive impairments across psychotic disorders and ASD are similar, suggesting that mechanisms that are known to underpin social impairments in ASD may also play a role in the impairments seen in psychosis. Specifically, in both humans and animal models of ASD, a cerebellar-parietal network has been identified that is directly related to social cognition and social functioning. In this study we examined social cognition and resting-state brain connectivity in people with psychosis and in neurotypical adults. We hypothesized that social cognition would be most strongly associated with cerebellar-parietal connectivity, even when using a whole-brain data driven approach. Methods: We examined associations between brain connectivity and social cognition in a trans-diagnostic sample of people with psychosis (n = 81) and neurotypical controls (n = 45). Social cognition was assessed using the social cognition domain score of the MATRICS Consensus Cognitive Battery. We used a multivariate pattern analysis to correlate social cognition with resting-state functional connectivity at the individual voxel level. Results: This approach identified a circuit between right cerebellar Crus I, II and left parietal cortex as the strongest correlate of social cognitive performance. This connectivity-cognition result was observed in both people with psychotic disorders and in neurotypical adults. Conclusions: Using a data-driven whole brain approach we identified a cerebellar-parietal circuit that was robustly associated with social cognitive ability, consistent with findings from people with ASD and animal models. These findings suggest that this circuit may be marker of social cognitive impairment trans-diagnostically and support cerebellar-parietal connectivity as a potential therapeutic target for enhancing social cognition.

White matter structure in schizophrenia and autism: Abnormal diffusion across the brain in schizophrenia

BACKGROUND

Schizophrenia and autism share many behavioral and neurological similarities, including altered white matter tract structure. However, because schizophrenia and autism are rarely compared directly, it is difficult to establish whether white matter abnormalities are disorder-specific or are common across these disorders that share some symptomatology.

METHODS

In the current study, we compared white matter water diffusion using tensor imaging in 25 adults with autism, 15 adults with schizophrenia, all with IQ scores above 88, and 19 neurotypical adults.

RESULTS

Although the three groups evinced no statistically significant differences in measures of fractional anisotropy (FA), the schizophrenia group showed significantly greater mean diffusivity (MD; Cohen's d > 0.77), due to greater radial diffusivity (RD; Cohen's d > 0.92), compared to both the autism and control groups. This effect was evident across the brain rather than specific to a particular tract.

CONCLUSIONS

The greater MD and RD in schizophrenia appears to be diagnosis-specific. The altered diffusion may reflect subtle abnormalities in myelination, which could be a potential mechanism underlying the widespread behavioral deficits associated with schizophrenia.

Transdiagnostic neuroimaging in psychiatry: A review

Transdiagnostic approach has a long history in neuroimaging, predating its recent ascendance as a paradigm for new psychiatric nosology. Various psychiatric disorders have been compared for commonalities and differences in neuroanatomical features and activation patterns, with different aims and rationales. This review covers both structural and functional neuroimaging publications with direct comparison of different psychiatric disorders, including schizophrenia, bipolar disorder, major depressive disorder, autism spectrum disorder, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, conduct disorder, anorexia nervosa, and bulimia nervosa. Major findings are systematically presented along with specific rationales for each comparison.

Simultaneous fMRI-EEG-DTI recording of MMN in patients with schizophrenia

Functional magnetic resonance imaging (fMRI), electroencephalogram (EEG), and diffusion tensor imaging (DTI) recording have complementary spatiotemporal resolution limitations but can be powerful methods when used together to enable both functional and anatomical modeling, with each neuroimaging procedure used to maximum advantage. We recorded EEGs during event-related fMRI followed by DTI in 15 healthy volunteers and 12 patients with schizophrenia using an omission mismatch negativity (MMN) paradigm. Blood oxygenation level-dependent (BOLD) signal changes were calculated in a region of interest (ROI) analysis, and fractional anisotropy (FA) in the white matter fibers related to each area was compared between groups using tract-specific analysis. Patients with schizophrenia had reduced BOLD activity in the left middle temporal gyrus, and BOLD activity in the right insula and right parahippocampal gyrus significantly correlated with positive symptoms on the Positive and Negative Syndrome Scale (PANSS) and hostility subscores. BOLD activation of Heschl’s gyri also correlated with the limbic system, including the insula. FA values in the left anterior cingulate cortex (ACC) significantly correlated with changes in the BOLD signal in the right superior temporal gyrus (STG), and FA values in the right ACC significantly correlated with PANSS scores. This is the first study to examine MMN using simultaneous fMRI, EEG, and DTI recording in patients with schizophrenia to investigate the potential implications of abnormalities in the ACC and limbic system, including the insula and parahippocampal gyrus, as well as the STG. Structural changes in the ACC during schizophrenia may represent part of the neural basis for the observed MMN deficits. The deficits seen in the feedback/feedforward connections between the prefrontal cortex and STG modulated by the ACC and insula may specifically contribute to impaired MMN generation and clinical manifestations.

Neuroanatomical deficits shared by youth with autism spectrum disorders and psychotic disorders

Autism spectrum disorders (ASD) and early-onset psychosis (EOP) are neurodevelopmental disorders that share genetic, clinical and cognitive facets; it is unclear if these disorders also share spatially overlapping cortical thickness (CT) and surface area (SA) abnormalities. MRI scans of 30 ASD, 29 patients with early-onset first-episode psychosis (EO-FEP) and 26 typically developing controls (TD) (age range 10-18 years) were analyzed by the FreeSurfer suite to calculate vertex-wise estimates of CT, SA, and cortical volume. Two publicly available datasets of ASD and EOP (age range 7-18 years and 5-17 years, respectively) were used for replication analysis. ASD and EO-FEP had spatially overlapping areas of cortical thinning and reduced SA in the bilateral insula (all p's < .00002); 37% of all left insular vertices presenting with significant cortical thinning and 20% (left insula) and 61% (right insula) of insular vertices displaying decreased SA overlapped across both disorders. In both disorders, SA deficits contributed more to cortical volume decreases than reductions in CT did. This finding, as well as the novel finding of an absence of spatial overlap (for ASD) or marginal overlap (for EOP) of deficits in CT and SA, was replicated in the two nonoverlapping independent samples. The insula appears to be a region with transdiagnostic vulnerability for deficits in CT and SA. The finding of nonexistent or small spatial overlap between CT and SA deficits in young people with ASD and psychosis may point to the involvement of common aberrant early neurodevelopmental mechanisms in their pathophysiology.

Ayres Theories of Autism and Sensory Integration Revisited: What Contemporary Neuroscience Has to Say

Abnormal sensory-based behaviors are a defining feature of autism spectrum disorders (ASD). Dr. A. Jean Ayres was the first occupational therapist to conceptualize Sensory Integration (SI) theories and therapies to address these deficits. Her work was based on neurological knowledge of the 1970’s. Since then, advancements in neuroimaging techniques make it possible to better understand the brain areas that may underlie sensory processing deficits in ASD. In this article, we explore the postulates proposed by Ayres (i.e., registration, modulation, motivation) through current neuroimaging literature. To this end, we review the neural underpinnings of sensory processing and integration in ASD by examining the literature on neurophysiological responses to sensory stimuli in individuals with ASD as well as structural and network organization using a variety of neuroimaging techniques. Many aspects of Ayres’ hypotheses about the nature of the disorder were found to be highly consistent with current literature on sensory processing in children with ASD but there are some discrepancies across various methodological techniques and ASD development. With additional characterization, neurophysiological profiles of sensory processing in ASD may serve as valuable biomarkers for diagnosis and monitoring of therapeutic interventions, such as SI therapy.

Insular function in autism: Update and future directions in neuroimaging and interventions

The insular cortex, hidden within the lateral sulcus of the human brain, participates in a range of cognitive, affective, and sensory functions. Autism spectrum disorder (ASD), a neurodevelopmental condition affecting all of these functional domains, has increasingly been linked with atypical activation and connectivity of the insular cortices. Here we review the latest research linking atypical insular function to a range of behaviors characteristic of ASD, with an emphasis on neuroimaging findings in the domains of social cognition and executive function. We summarize some of the recent work linking the insula to interventions in autism, including oxytocin-based pharmacological treatments and music therapy. We suggest that future directions likely to yield significant insights into insular pathology in ASD include the analysis of the dynamics of this brain region. We also conclude that more basic research is necessary on the use of oxytocin pharmacotherapy, and larger studies addressing participant heterogeneity are needed on the use of music therapy in ASD. Long-term studies are needed to ascertain sustained effects of these interventions.

Variation in fourteen brain structure volumes in schizophrenia: A comprehensive meta-analysis of 246 studies

Despite hundreds of structural MRI studies documenting smaller brain volumes on average in schizophrenia compared to controls, little attention has been paid to group differences in the variability of brain volumes. Examination of variability may help interpret mean group differences in brain volumes and aid in better understanding the heterogeneity of schizophrenia. Variability in 246 MRI studies was meta-analyzed for 13 structures that have shown medium to large mean effect sizes (Cohen's d≥0.4): intracranial volume, total brain volume, lateral ventricles, third ventricle, total gray matter, frontal gray matter, prefrontal gray matter, temporal gray matter, superior temporal gyrus gray matter, planum temporale, hippocampus, fusiform gyrus, insula; and a control structure, caudate nucleus. No significant differences in variability in cortical/subcortical volumes were detected in schizophrenia relative to controls. In contrast, increased variability was found in schizophrenia compared to controls for intracranial and especially lateral and third ventricle volumes. These findings highlight the need for more attention to ventricles and detailed analyses of brain volume distributions to better elucidate the pathophysiology of schizophrenia.

Do patients with high-functioning autism have similar social cognitive deficits as patients with a chronic cause of schizophrenia?

OBJECTIVE

There is substantial evidence that both patients with schizophrenia and patients with autism spectrum disorders (ASD) have impaired social cognition including theory of mind (ToM) deficits. However, it remains unclear if both verbal (explicit) and non-verbal (implicit) ToM as well as social perception are similarly affected in both disorders.

METHODS

Twenty-one patients diagnosed with schizophrenia and 11 patients diagnosed with ASD were matched one-to-one to healthy controls based on gender, age, and educational level. Social functioning was measured by Personal and Social Performance (PSP) scale. Neurocognition was measured using Brief Assessment of Cognition in Schizophrenia (BACS-DK), and four subtests from Wechsler Adult Intelligence (WAIS-IV) scale were applied to estimate IQ. The Animated Triangles Task was used to measure implicit ToM, while explicit ToM and social perception were measured by The Awareness and Social Inference Test (TASIT).

RESULTS

Patients with schizophrenia had deficits in implicit ToM and complex social perception compared to their matched controls, but no problems with explicit ToM. Surprisingly, patients with ASD solely had deficits with regard to complex social perception compared to their matched controls. The two patient groups were similar regarding estimated IQ, social functioning and years of education, but differed in age and neurocognition. When adjusting the p-values for age and neurocognitive deficits, both patients groups had similar social cognitive deficits.

CONCLUSIONS

Results imply that we compared schizophrenia patients with substantial neurocognitive deficits to a group of high-functioning patients with ASD. However, these two subgroups may have the same level of social cognitive deficits.

Diametrical relationship between gray and white matter volumes in autism spectrum disorder and schizophrenia

Autism spectrum disorders and schizophrenia have been variously characterized as separate nosological entities with overlapping deficits in social cognition or diametrical extremes of a phenotypic continuum. This study aimed to determine how these models apply to comparative morphometric data. MRI scans of the brain were obtained in 49 subjects with schizophrenia, 20 subjects with autism and 39 healthy controls. Images were parcellated into 40 Brodmann areas and entered into repeated-measures ANOVA for between-group comparison of global and localized gray and white matter volumes. A pattern of lower gray mater volumes and greater white matter volumes was found in subjects with schizophrenia in comparison to subjects with autism. For both gray and white matter, this pattern was most pronounced in regions associated with motor-premotor and anterior frontal cortex, anterior cingulate, fusiform, superior and middle temporal gyri. Patient groups tended to diverge from healthy controls in opposite directions, with greater-than-normal gray matter volumes and lower-than-normal white matter volumes in subjects with autism and reversed patterns in subjects with schizophrenia. White matter reductions in subjects with autism were seen in posterior frontal lobe and along the cingulate arch. Normal hemispheric asymmetry in the temporal lobe was effaced in subjects with autism and schizophrenia, especially in the latter. Nearly identical distribution of changes and diametrically divergent volumetry suggest that autism and schizophrenia may occupy opposite extremes of the same cognitive continuum.

Altered Anterior Insular Asymmetry in Pre-teen and Adolescent Youth with Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is hallmarked by social-emotional reciprocity deficits. Social-emotional responding requires the clear recognition of social cues as well as the internal monitoring of emotional salience. Insular cortex is central to the salience network, and plays a key role in approach-avoidance emotional valuation. Consistent right anterior insular hypoactivity and variable volumetric differences of insular cortical volumes were shown previously. The current study analyzed anterior and posterior insular volume/asymmetry changes in ASD across age. Age was used as an additional grouping variable as previous studies indicated differential regional volume in ASD individuals before and after puberty onset. In the current sample, pre-teen ASD expressed left lateralized anterior insula, while adolescent ASD had right lateralization. Typically developing (TD) individuals expressed the opposite lateralization of anterior insula in both age-groups (right greater than left anterior insular volume among pre-teen TD and left greater than right anterior insular volume among adolescent TD). Social-emotional calibrated severity scores from the ADOS were positively correlated with leftward anterior insular asymmetry and negatively correlated with proportional right anterior insular volumes in ASD. Insular cortex has a lateralized role in autonomic nervous system regulation (parasympathetic control in the left, sympathetic control in the right). Atypical insular asymmetry in ASD may contribute to the development of networks with a diminished salience signal to human faces and voices, and may lead to more learned passive avoidant responses to such stimuli at younger ages, leading to more distressed responses in adolescence. Data here supports the use of early behavioral intervention to increase awareness of and reward for social-emotional cues.

Autism: a transdiagnostic, dimensional, construct of reasoning?

The concept of autism has changed across time, from the Bleulerian concept, which defined it as one of several symptoms of dementia praecox, to the present-day concept representing a pervasive development disorder. The present theoretical contribution to this special issue of EJN on autism introduces new theoretical ideas and discusses them in light of selected prior theories, clinical examples, and recent empirical evidence. The overall aim is to identify some present challenges of diagnostic practice and autism research and to suggest new pathways that may help direct future research. Future research must agree on the definitions of core concepts such as autism and psychosis. A possible redefinition of the concept of autism may be a condition in which the rationale of an individual's behaviour differs qualitatively from that of the social environment due to characteristic cognitive impairments affecting reasoning. A broad concept of psychosis could focus on deviances in the experience of reality resulting from impairments of reasoning. In this light and consistent with recent empirical evidence, it may be appropriate to redefine dementia praecox as a developmental disorder of reasoning. A future challenge of autism research may be to develop theoretical models that can account for the impact of complex processes acting at the social level in addition to complex neurobiological and psychological processes. Such models could profit from a distinction among processes related to (i) basic susceptibility, (ii) adaptive processes and (iii) decompensating factors involved in the development of manifest illness.

Brain structure in autism: a voxel-based morphometry analysis of the Autism Brain Imaging Database Exchange (ABIDE)

Increased brain volume is a consistent finding in young children with autism spectrum disorders (ASD); however, the regional specificity and developmental course of abnormal brain structure are less clear. Small sample sizes, particularly among voxel-based morphometry (VBM) investigations, likely contribute to this difficulty. Recently established large-scale neuroimaging data repositories have helped clarify the neuroanatomy of neuropsychiatric disorders such as schizophrenia and may prove useful in ASD. Structural brain images from the Autism Brain Imaging Database Exchange (ABIDE), which contains over 1100 participants, were analyzing using DARTEL VBM to investigate total brain and tissue volumes, and regional brain structure abnormalities in ASD. Two, overlapping cohorts were analyzed; an 'All Subjects' cohort (n = 833) that included all individuals with usable MRI data, and a 'Matched Samples' cohort (n = 600) comprised of ASD and TD individuals matched, within each site, on age and sex. Total brain and grey matter volumes were enlarged by approximately 1-2 % in ASD; however, the effect reached statistical significance in only the All Subjects cohort. Within the All Subjects cohort, VBM analysis revealed enlargement of the left anterior superior temporal gyrus in ASD. No significant regional changes were detected in the Matched Samples cohort. There was a non-significant reduction in the correlation between IQ and TBV in ASD compared to TD. Brain structure abnormalities in ASD individuals age 6 and older consists of a subtle increase in total brain volume due to enlargement of grey matter with little evidence of regionally specific effects.

Methylphenidate induces state-dependency of social recognition learning: Central components

Methylphenidate (MPH) is a widely prescribed drug for the treatment of attention-deficit hyperactivity disorder. Findings in the literature suggest that the effects of MPH on memory may result from increased extracellular levels of norepinephrine (NE) and dopamine (DA). Here, we report that the systemic administration of MPH before the acquisition phase in a social discrimination task impaired the retrieval of the social recognition memory (SRM), but made it state-dependent: another administration of MPH before the retention test recovered the SRM. We observed that the induction of state dependency by MPH relies on the ventromedial prefrontal cortex (vmPFC), but not on the CA1 region of the hippocampus (CA1). Also, the inhibitors of NE and DA, nisoxetine and GBR12909, respectively, restored the SRM when infused into the vmPFC. Only the GBR12909 was able to restore the SRM in the CA1, whereas nisoxetine could not restore and even caused an impairment on memory retrieval when infused alone before the retention test. The data suggest that the state-dependence of SRM induced by MPH depends on an influence of both catecholamines on the vmPFC, while NE inhibits the retrieval of SRM on the hippocampus.

Transdiagnostic deviant facial recognition for implicit negative emotion in autism and schizophrenia

Impaired facial affect recognition (FAR) is observed in schizophrenia and autism spectrum disorder (ASD) and has been linked to amygdala and fusiform gyrus dysfunction. ASD patient's impairments seem to be more pronounced during implicit rather than explicit FAR, whereas for schizophrenia data are inconsistent. However, there are no studies comparing both patient groups in an identical design. The aim of this three-group study was to identify (i) whether FAR alterations are equally present in both groups, (ii) whether they are present rather during implicit or explicit FAR, (iii) and whether they are conveyed by similar or disorder-specific neural mechanisms. Using fMRI, we investigated neural activation during explicit and implicit negative and neutral FAR in 33 young-adult individuals with ASD, 20 subjects with paranoid-schizophrenia and 25 IQ- and gender-matched controls individuals. Differences in activation patterns between each clinical group and controls, respectively were found exclusively for implicit FAR in amygdala and fusiform gyrus. In addition, the ASD group additionally showed reduced activations in medial prefrontal cortex (PFC), bilateral dorso-lateral PFC, ventro-lateral PFC, posterior-superior temporal sulcus and left temporo-parietal junction. Although subjects with ASD showed more widespread altered activation patterns, a direct comparison between both patient groups did not show disorder-specific deficits in neither patient group. In summary, our findings are consistent with a common neural deficit during implicit negative facial affect recognition in schizophrenia and autism spectrum disorders.

Magnetoencephalography reveals an increased non-target P3a, but not target P3b, that is associated with high non-clinical psychosocial deficits

Auditory processing deficits are frequently identified in autism and schizophrenia, and the two disorders have been shown to share psychosocial difficulties. This study used magnetoencephalography to investigate auditory processing differences for those with a high degree of a non-clinical autistic and schizotypal trait phenotype, Social Disorganisation (SD). Participants were 18 low (9 female) and 19 high (9 female) SD scorers (18-40 years) who completed a three-stimulus auditory oddball paradigm of speech sounds (standard: 100ms 'o', deviant: 150ms 'o', novel: 150ms 'e'). Spatio-temporal cluster analysis revealed increased amplitude for the high SD group in a left (p = 0.006) and a right (p = 0.020) hemisphere cluster in response to the novel non-target. No cluster differences were found in response to the target deviant. These findings suggest that those with a high degree of the SD phenotype recruit more cortical resources when processing unattended, novel speech stimuli, which may lead to psychosocial deficits.

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.

Autism spectrum disorder and schizophrenia: boundaries and uncertainties

Autism and schizophrenia were placed in different diagnostic categories in DSM-III, having previously been considered as related diagnostic entities. New evidence suggests that these disorders show clinical and cognitive deficit overlaps and shared neurobiological characteristics. Furthermore, children presenting with both autism spectrum disorder (ASD) and psychotic experiences may represent a subgroup of ASD more closely linked to psychosis. The study of ASD and childhood schizophrenia, and their clinical boundaries and overlapping pathophysiological characteristics, may clarify their relationship and lead to more effective interventions. This article discusses the relationship through a critical review of current and historical dilemmas surrounding the phenomenology and pathophysiology of these disorders. It provides a framework for working with children and young people with mixed clinical presentations, illustrated by three brief fictional case vignettes.

Increased Left Inferior Temporal Gyrus Was Found in Both Low Function Autism and High Function Autism

Previous neuroimaging studies of autism spectrum disorder (ASD) have focused on subjects with IQ > 70 or ASD without considering IQ levels. It remains unclear whether differences in brain anatomy in this population are associated with variations in clinical phenotype. In this study, 19 children with low functioning autism (LFA) and 19 children with high functioning autism (HFA) were compared with 27 healthy controls (HC). We found increased gray matter volume (GMV) in the left inferior temporal gyrus in subjects with both HFA and LFA and increased GMV of left middle temporal gyrus BA21 was found only in the LFA group. A significant negative correlation was found between the left inferior temporal gyrus (LITG) and the score of repetitive behavior in the HFA group.

Social Cognition in Schizophrenia and Autism Spectrum Disorders: A Systematic Review and Meta-Analysis of Direct Comparisons

Background: Deficits in social cognition are well-recognized in both schizophrenia and autism spectrum disorders (ASD). However, it is less clear how social cognition deficits differ between both disorders and what distinct mechanisms may underlie such differences. We aimed at reviewing available evidence from studies directly comparing social cognitive performance between individuals with schizophrenia and ASD. Methods: We performed a systematic review of literature up to May 22, 2018 on Pubmed, Web of Science, and Scopus. Search terms included combinations of the keywords "social cognition," "theory of mind," "autism," "Asperger," "psychosis," and "schizophrenia." Two researchers independently selected and extracted data according to PRISMA guidelines. Random-effects meta-analyses were conducted for performance on social cognitive tasks evaluating: (1) emotion perception; (2) theory of mind (ToM); (3) emotional intelligence (managing emotions score of the Mayer-Salovey-Caruso Emotional Intelligence Test); and (4) social skills. Results: We identified 19 eligible studies for meta-analysis including a total of 1,040 patients (558 with schizophrenia and 482 with ASD). Eight studies provided data on facial emotion perception that evidenced a better performance by participants with schizophrenia compared to those with ASD (Hedges' g = 0.43; p = 0.031). No significant differences were found between groups in the Reading the Mind in the Eyes Test (8 studies; Hedges' g = 0.22; p = 0.351), other ToM tasks (9 studies; Hedges' g = -0.03; p = 0.903), emotional intelligence (3 studies; Hedges' g = -0.17; p = 0.490), and social skills (3 studies; Hedges' g = 0.86; p = 0.056). Participants' age was a significant moderator of effect size in emotion perception and RMET analyzes, with larger differences favoring patients with schizophrenia being observed in studies with younger participants. Conclusions: The instruments that are currently available to evaluate social cognition poorly differentiate between individuals with schizophrenia and ASD. Combining behavioral tasks with neurophysiologic assessments may better characterize the differences in social cognition between both disorders.

Insular pathology in young people with high-functioning autism and first-episode psychosis

BACKGROUND

Autism Spectrum Disorders (ASD) and psychosis share deficits in social cognition. The insular region has been associated with awareness of self and reality, which may be basic for proper social interactions.

METHODS

Total and regional insular volume and thickness measurements were obtained from a sample of 30 children and adolescents with ASD, 29 with early onset first-episode psychosis (FEP), and 26 healthy controls (HC). Total, regional, and voxel-level volume and thickness measurements were compared between groups (with correction for multiple comparisons), and the relationship between these measurements and symptom severity was explored.

RESULTS

Compared with HC, a shared volume deficit was observed for the right (but not the left) anterior insula (ASD: p = 0.007, FEP: p = 0.032), and for the bilateral posterior insula: (left, ASD: p = 0.011, FEP: p = 0.033; right, ASD: p = 0.004, FEP: p = 0.028). A voxel-based morphometry (VBM) conjunction analysis showed that ASD and FEP patients shared a gray matter volume and thickness deficit in the left posterior insula. Within patients, right anterior (r = -0.28, p = 0.041) and left posterior (r = -0.29, p = 0.030) insular volumes negatively correlated with the severity of insight deficits, and left posterior insular volume negatively correlated with the severity of 'autistic-like' symptoms (r = -0.30, p = 0.028).

CONCLUSIONS

The shared reduced volume and thickness in the anterior and posterior regions of the insula in ASD and FEP provides the first tentative evidence that these conditions share structural pathology that may be linked to shared symptomatology.

Social-cognitive brain function and connectivity during visual perspective-taking in autism and schizophrenia

BACKGROUND

Autism spectrum disorder (ASD) and schizophrenia are neurodevelopmental conditions that are characterized by significant social impairment. Emerging genomic and neurobiological evidence has increasingly pointed to shared pathophysiologic mechanisms in the two disorders. Overlap in social impairment may reflect similar underlying neural dysfunction in social-cognitive brain networks, yet few studies have directly compared brain function and communication between those with ASD and schizophrenia.

METHODS

Outpatients with schizophrenia (n=36), ASD (n=33), and healthy volunteers (n=37) completed a visual perspective-taking task during functional neuroimaging at 3T to assess similarities and differences in fronto-temporal brain function and connectivity during social-cognitive processing. Analyses employed general linear models to examine differences in amplitude of BOLD-signal response between disorder groups, and computed functional connectivity coefficients to investigate differences in the connectivity profiles of networks implicated in social cognition.

RESULTS

Despite similar behavioral impairments, participants with ASD and schizophrenia evidenced distinct neural abnormalities during perspective-taking. Functional activation results indicated reduced temporo-parietal junction and medial prefrontal activity in ASD compared to schizophrenia (all P_uncor<0.002). Functional connectivity analyses further revealed significantly greater local orbitofrontal connectivity in ASD than schizophrenia (all P_FDR<0.028) during perspective-taking. Differences in brain activation and connectivity were unrelated to antipsychotic medication dose.

CONCLUSIONS

Autism and schizophrenia are characterized by similar social-cognitive impairments that may stem from different underlying abnormalities in the functional organization and communication of the social brain.

Spatio-temporal source cluster analysis reveals fronto-temporal auditory change processing differences within a shared autistic and schizotypal trait phenotype

Social Disorganisation (SD) is a shared autistic and schizotypal phenotype that is present in the subclinical population. Auditory processing deficits, particularly in mismatch negativity/field (MMN/F) have been reported across both spectrum disorders. This study investigates differences in MMN/F cortical spatio-temporal source activity between higher and lower quintiles of the SD spectrum.

Sixteen low (9 female) and 19 high (9 female) SD subclinical adults (18–40years) underwent magnetoencephalography (MEG) during an MMF paradigm where standard tones (50ms) were interrupted by infrequent duration deviants (100ms).

Spatio-temporal source cluster analysis with permutation testing revealed no difference between the groups in source activation to the standard tone. To the deviant tone however, there was significantly reduced right hemisphere fronto-temporal and insular cortex activation for the high SD group (p= 0.038). The MMF, as a product of the cortical response to the deviant minus that to the standard, did not differ significantly between the high and low Social Disorganisation groups.

These data demonstrate a deficit in right fronto-temporal processing of an auditory change for those with more of the shared SD phenotype, indicating that right fronto-temporal auditory processing may be associated with psychosocial functioning.

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Autism and schizotypal spectra share a trait phenotype, Social Disorganisation (SD).

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Auditory mismatch paradigm demonstrates processing differences between high and low SD.

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High SD scorers have reduced fronto-temporal response to auditory change.

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Reduced fronto-temporal source activation in high SD is right lateralised.

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Psychosocial function is related to auditory deviant processing.

Autism Tendencies and Psychosis Proneness Interactively Modulate Saliency Cost

Atypical responses to salient information are a candidate endophenotype for both autism and psychosis spectrum disorders. The present study investigated the costs and benefits of such atypicalities for saliency-based selection in a large cohort of neurotypical adults in whom both autism and psychosis expressions were assessed. Two experiments found that autism tendencies and psychosis proneness interactively modulated the cost incurred in the presence of a task-irrelevant salient distractor. Specifically, expressions of autism and psychosis had opposing effects on responses to salient information such that the benefits associated with high expressions for autism offset costs associated with high expressions for psychosis. The opposing influences observed on saliency cost may be driven by distinct attentional mechanisms that are differentially affected by expressions for autism and psychosis.

Major neurotransmitter systems in dorsal hippocampus and basolateral amygdala control social recognition memory

Social recognition memory (SRM) is crucial for reproduction, forming social groups, and species survival. Despite its importance, SRM is still relatively little studied. Here we examine the participation of the CA1 region of the dorsal hippocampus (CA1) and the basolateral amygdala (BLA) and that of dopaminergic, noradrenergic, and histaminergic systems in both structures in the consolidation of SRM. Male Wistar rats received intra-CA1 or intra-BLA infusions of different drugs immediately after the sample phase of a social discrimination task and 24-h later were subjected to a 5-min retention test. Animals treated with the protein synthesis inhibitor, anisomycin, into either the CA1 or BLA were unable to recognize the previously exposed juvenile (familiar) during the retention test. When infused into the CA1, the β-adrenoreceptor agonist, isoproterenol, the D1/D5 dopaminergic receptor antagonist, SCH23390, and the H2 histaminergic receptor antagonist, ranitidine, also hindered the recognition of the familiar juvenile 24-h later. The latter drug effects were more intense in the CA1 than in the BLA. When infused into the BLA, the β-adrenoreceptor antagonist, timolol, the D1/D5 dopamine receptor agonist, SKF38393, and the H2 histaminergic receptor agonist, ranitidine, also hindered recognition of the familiar juvenile 24-h later. In all cases, the impairment to recognize the familiar juvenile was abolished by the coinfusion of agonist plus antagonist. Clearly, both the CA1 and BLA, probably in that order, play major roles in the consolidation of SRM, but these roles are different in each structure vis-à-vis the involvement of the β-noradrenergic, D1/D5-dopaminergic, and H2-histaminergic receptors therein.

Similar white matter but opposite grey matter changes in schizophrenia and high-functioning autism

OBJECTIVE

High-functioning autism (HFA) and schizophrenia (SZ) are two of the main neurodevelopmental disorders, sharing several clinical dimensions and risk factors. Their exact relationship is poorly understood, and few studies have directly compared both disorders. Our aim was thus to directly compare neuroanatomy of HFA and SZ using a multimodal MRI design.

METHODS

We scanned 79 male adult subjects with 3T MRI (23 with HFA, 24 with SZ and 32 healthy controls, with similar non-verbal IQ). We compared them using both diffusion-based whole-brain tractography and T1 voxel-based morphometry.

RESULTS

HFA and SZ groups exhibited similar white matter alterations in the left fronto-occipital inferior fasciculus with a decrease in generalized fractional anisotropy compared with controls. In grey matter, the HFA group demonstrated bilateral prefrontal and anterior cingulate increases in contrast with prefrontal and left temporal reductions in SZ.

CONCLUSION

HFA and SZ may share common white matter deficits in long-range connections involved in social functions, but opposite grey matter abnormalities in frontal regions that subserve complex cognitive functions. Our results are consistent with the fronto-occipital underconnectivity theory of HFA and the altered connectivity hypothesis of SZ and suggest the existence of both associated and diametrical liabilities to these two conditions.

Sex differences in structural organization of motor systems and their dissociable links with repetitive/restricted behaviors in children with autism

Background

Autism spectrum disorder (ASD) is diagnosed much less often in females than males. Emerging behavioral accounts suggest that the clinical presentation of autism is different in females and males, yet research examining sex differences in core symptoms of autism in affected children has been limited. Additionally, to date, there have been no systematic attempts to characterize neuroanatomical differences underlying the distinct behavioral profiles observed in girls and boys with ASD. This is in part because extant ASD studies have included a small number of girls.

Methods

Leveraging the National Database for Autism Research (NDAR), we first analyzed symptom severity in a large sample consisting of 128 ASD girls and 614 age- and IQ-matched ASD boys. We then examined symptom severity and structural imaging data using novel multivariate pattern analysis in a well-matched group of 25 ASD girls, 25 ASD boys, 19 typically developing (TD) girls, and 19 TD boys, obtained from the Autism Brain Imaging Data Exchange (ABIDE).

Results

In both the NDAR and ABIDE datasets, girls, compared to boys, with ASD showed less severe repetitive/restricted behaviors (RRBs) and comparable deficits in the social and communication domains. In the ABIDE imaging dataset, gray matter (GM) patterns in the motor cortex, supplementary motor area (SMA), cerebellum, fusiform gyrus, and amygdala accurately discriminated girls and boys with ASD. This sex difference pattern was specific to ASD as the GM in these brain regions did not discriminate TD girls and boys. Moreover, GM in the motor cortex, SMA, and crus 1 subdivision of the cerebellum was correlated with RRB in girls whereas GM in the right putamen—the region that discriminated TD girls and boys—was correlated with RRB in boys.

Conclusions

We found robust evidence for reduced levels of RRB in girls, compared to boys, with ASD, providing the strongest evidence to date for sex differences in a core phenotypic feature of childhood ASD. Sex differences in brain morphometry are prominent in the motor system and in areas that comprise the “social brain.” Notably, RRB severity is associated with sex differences in GM morphometry in distinct motor regions. Our findings provide novel insights into the neurobiology of sex differences in childhood autism.

Electronic supplementary material

The online version of this article (doi:10.1186/s13229-015-0042-z) contains supplementary material, which is available to authorized users.