Autism from developmental and neuropsychological perspectives

Amygdala connectivity and implications for social cognition and disorders

The amygdala is a hub of subcortical region that is crucial in a wide array of affective and motivation-related behaviors. While early research contributed significantly to our understanding of this region's extensive connections to other subcortical and cortical regions, recent methodological advances have enabled researchers to better understand the details of these circuits and their behavioral contributions. Much of this work has focused specifically on investigating the role of amygdala circuits in social cognition. In this chapter, we review both long-standing knowledge and novel research on the amygdala's structure, function, and involvement in social cognition. We focus specifically on the amygdala's circuits with the medial prefrontal cortex, the orbitofrontal cortex, and the hippocampus, as these regions share extensive anatomic and functional connections with the amygdala. Furthermore, we discuss how dysfunction in the amygdala may contribute to social deficits in clinical disorders including autism spectrum disorder, social anxiety disorder, and Williams syndrome. We conclude that social functions mediated by the amygdala are orchestrated through multiple intricate interactions between the amygdala and its interconnected brain regions, endorsing the importance of understanding the amygdala from network perspectives.

Autism and Williams syndrome: truly mirror conditions in the socio-cognitive domain?

Autism Spectrum Disorders (ASD) and Williams Syndrome (WS) are frequently characterized as mirror conditions in the socio-cognitive domain, with ASD entailing restrictive social interests and with WS exhibiting hypersociability. In this review paper, we examine in detail the strong points and deficits of people with ASD or WS in the socio-cognitive domain and show that both conditions also share some common features. Moreover, we explore the neurobiological basis of the social profile of ASD and WS and found a similar mixture of common affected areas and condition-specific impaired regions. We discuss these findings under the hypothesis of a continuum of the socio-cognitive abilities in humans.

Natural Products and Their Therapeutic Effect on Autism Spectrum Disorder

Autism is a complex neurodevelopmental disorder that is evident in early childhood and can persist throughout the entire life. The disease is basically characterized by hurdles in social interaction where the individuals demonstrate repetitive and stereotyped interests or patterns of behavior. A wide number of neuroanatomical studies with autistic patients revealed alterations in brain development which lead to diverse cellular and anatomical processes including atypical neurogenesis, neuronal migration, maturation, differentiation, and degeneration. Special education programs, speech and language therapy, have been employed for the amelioration of behavioral deficits in autism. Although commonly prescribed antidepressants, antipsychotics, anticonvulsants, and stimulants have revealed satisfactory responses in autistic individuals, adverse side effects and increased risk of several other complications including obesity, dyslipidemia, diabetes mellitus, thyroid disorders, etc. have compelled the researchers to turn their attention toward herbal remedies. Alternative approaches with natural compounds are on continuous clinical trial to confirm their efficacy and to understand their potential in autism treatment. This chapter aims to cover the major plant-based natural products which hold promising outcomes in the field of reliable therapeutic interventions for autism.

Attentional network deficits in children with autism spectrum disorder

STATEMENT OF PURPOSE

Individuals with autism spectrum disorder (ASD) often demonstrate deficient attentional ability, but the specific nature of the deficit is unclear. The Attention Networks model provides a useful approach to deconstruct this attentional deficit into its component parts.

METHOD

Fifty-two neurotypical (NT) children and 14 children with ASD performed the child version of the Attention Network Test (ANT). The latter requires participants to indicate the direction of a centre target stimulus, which is presented above/below fixation and sometimes flanked by either congruent or incongruent distractor stimuli.

RESULTS

Relative to NT children, those with ASD were: (1) slower to react to spatially cued trials and (2) more error prone on executive (conflict) attention trials.

CONCLUSIONS

Young children with ASD have intact alerting attention, but less-efficient orienting and executive attention.

Ketogenic diet restores aberrant cortical motor maps and excitation-to-inhibition imbalance in the BTBR mouse model of autism spectrum disorder

Autism spectrum disorder (ASD) is an increasingly prevalent neurodevelopmental disorder characterized by deficits in sociability and communication, and restricted and/or repetitive motor behaviors. Amongst the diverse hypotheses regarding the pathophysiology of ASD, one possibility is that there is increased neuronal excitation, leading to alterations in sensory processing, functional integration and behavior. Meanwhile, the high-fat, low-carbohydrate ketogenic diet (KD), traditionally used in the treatment of medically intractable epilepsy, has already been shown to reduce autistic behaviors in both humans and in rodent models of ASD. While the mechanisms underlying these effects remain unclear, we hypothesized that this dietary approach might shift the balance of excitation and inhibition towards more normal levels of inhibition. Using high-resolution intracortical microstimulation, we investigated basal sensorimotor excitation/inhibition in the BTBR T+Itpr(tf)/J (BTBR) mouse model of ASD and tested whether the KD restores the balance of excitation/inhibition. We found that BTBR mice had lower movement thresholds and larger motor maps indicative of higher excitation/inhibition compared to C57BL/6J (B6) controls, and that the KD reversed both these abnormalities. Collectively, our results afford a greater understanding of cortical excitation/inhibition balance in ASD and may help expedite the development of therapeutic approaches aimed at improving functional outcomes in this disorder.

Two Polarities of Attention in Social Contexts: From Attending-to-Others to Attending-to-Self

Social attention is one special form of attention that involves the allocation of limited processing resources in a social context. Previous studies on social attention often regard how attention is directed toward socially relevant stimuli such as faces and gaze directions of other individuals. In contrast to attending-to-others, a different line of researches has shown that self-related information such as own face and name automatically captures attention and is preferentially processed comparing to other-related information. These contrasting behavioral effects between attending-to-others and attending-to-self prompt me to consider a synthetic viewpoint for understanding social attention. I propose that social attention operates at two polarizing states: In one extreme, individual tends to attend to the self and prioritize self-related information over others', and, in the other extreme, attention is allocated to other individuals to infer their intentions and desires. Attending-to-self and attending-to-others mark the two ends of an otherwise continuum spectrum of social attention. For a given behavioral context, the mechanisms underlying these two polarities will interact and compete with each other in order to determine a saliency map of social attention that guides our behaviors. An imbalanced competition between these two behavioral and cognitive processes will cause cognitive disorders and neurological symptoms such as autism spectrum disorders and Williams syndrome. I have reviewed both behavioral and neural evidence that support the notion of polarized social attention, and have suggested several testable predictions to corroborate this integrative theory for understanding social attention.

NOMA-GAP/ARHGAP33 regulates synapse development and autistic-like behavior in the mouse

Neuropsychiatric developmental disorders, such as autism spectrum disorders (ASDs) and schizophrenia, are typically characterized by alterations in social behavior and have been linked to aberrant dendritic spine and synapse development. Here we show, using genetically engineered mice, that the Cdc42 GTPase-activating multiadaptor protein, NOMA-GAP, regulates autism-like social behavior in the mouse, as well as dendritic spine and synapse development. Surprisingly, we were unable to restore spine morphology or autism-associated social behavior in NOMA-GAP-deficient animals by Cre-mediated deletion of Cdc42 alone. Spine morphology can be restored in vivo by re-expression of wild-type NOMA-GAP or a mutant of NOMA-GAP that lacks the RhoGAP domain, suggesting that other signaling functions are involved. Indeed, we show that NOMA-GAP directly interacts with several MAGUK (membrane-associated guanylate kinase) proteins, and that this modulates NOMA-GAP activity toward Cdc42. Moreover, we demonstrate that NOMA-GAP is a major regulator of PSD-95 in the neocortex. Loss of NOMA-GAP leads to strong upregulation of serine 295 phosphorylation of PSD-95 and moreover to its subcellular mislocalization. This is associated with marked loss of surface α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor and defective synaptic transmission, thereby providing a molecular basis for autism-like social behavior in the absence of NOMA-GAP.

Integrated play groups: promoting symbolic play and social engagement with typical peers in children with ASD across settings

Children with autism spectrum disorders (ASD) face pervasive challenges in symbolic and social play development. The Integrated Play Groups (IPG) model provides intensive guidance for children with ASD to participate with typical peers in mutually engaging experiences in natural settings. This study examined the effects of a 12-week IPG intervention on the symbolic and social play of 48 children with ASD using a repeated measures design. The findings revealed significant gains in symbolic and social play that generalized to unsupported play with unfamiliar peers. Consistent with prior studies, the outcomes provide robust and compelling evidence that further validate the efficacy of the IPG model. Theoretical and practical implications for maximizing children's developmental potential and social inclusion in play are discussed.

Altered white matter connectivity as a neural substrate for social impairment in Autism Spectrum Disorder

BACKGROUND

Autism Spectrum Disorder (ASD) symptoms have been hypothesized to result from altered brain connectivity. The 'disconnectivity' hypothesis has been used to explain characteristic impairments in socio-emotional function, observed clinically in ASD. Here, we review the evidence for impaired white matter connectivity as a neural substrate for socio-emotional dysfunction in ASD. A review of diffusion tensor imaging (DTI) studies, and focused discussion of relevant post-mortem, structural, and functional neuroimaging studies, is provided.

METHODS

Studies were identified using a sensitive search strategy in MEDLINE, Embase and PsycINFO article databases using the OvidSP database interface. Search terms included database subject headings for the concepts of pervasive developmental disorders, and DTI. Seventy-two published DTI studies examining white matter microstructure in ASD were reviewed. A comprehensive discussion of DTI studies that examined white matter tracts linking socio-emotional structures is presented.

RESULTS

Several DTI studies reported microstructural differences indicative of developmental alterations in white matter organization, and potentially myelination, in ASD. Altered structure within long-range white matter tracts linking socio-emotional processing regions was implicated. While alterations of the uncinate fasciculus and frontal and temporal thalamic projections have been associated with social symptoms in ASD, few studies examined association of tract microstructure with core impairment in this disorder.

CONCLUSIONS

The uncinate fasciculus and frontal and temporal thalamic projections mediate limbic connectivity and integrate structures responsible for complex socio-emotional functioning. Impaired development of limbic connectivity may represent one neural substrate contributing to ASD social impairments. Future efforts to further elucidate the nature of atypical white matter development, and its relationship to core symptoms, may offer new insights into etiological mechanisms contributing to ASD impairments and uncover novel opportunities for targeted intervention.

Quality of life: a case-controlled long-term follow-up study, comparing young high-functioning adults with autism spectrum disorders with adults with other psychiatric disorders diagnosed in childhood

BACKGROUND

Long term outcome in childhood autism spectrum disorders (ASD) was evaluated by studying quality of life (QoL) in young adulthood in comparison to the outcome of other child psychiatric disorders.

METHODS

In this follow-up study, objective and subjective QoL of 169 high-functioning (IQ>70) adults with ASD (19 to 30 years) was contrasted with QoL data of age matched adults diagnosed with attention deficit/hyperactivity disorder (N=85), disruptive behaviour disorders (N=83), and affective disorders (N=85) during childhood. The mean follow-up period of the ASD patients was 13.9 years. Objective QoL included marital status, living arrangements, level of education, employment, and usage of mental health care. Subjective QoL included satisfaction concerning living arrangements, work or education, physical condition, partner relationship, social relationships, state of mind, and future perspective.

RESULTS

QoL was more compromised in adults diagnosed with ASD in childhood than in adults with other psychiatric disorders in childhood. A relatively large proportion of the adults with ASD were single, few lived with a partner or a family and many of them were institutionalized. Adults with ASD had lower educational levels, relatively few had paid employment and many were social security recipients, as compared to the other psychiatric patients. In case the adults with ASD used medication, 47% used anti-psychotics. Regarding the subjective QoL, the adults with ASD were less satisfied about their work or education, partner relationship, and future perspective than the other groups. Even when highly educated adults with ASD were compared to highly educated adults diagnosed with other childhood disorders, the QoL appeared to be more disadvantageous in adults with ASD.

CONCLUSION

Many studies have shown that QoL is threatened in psychiatric patients, but findings of this study indicate that young high-functioning adults diagnosed with ASD in childhood are at relatively high risk for poor QoL compared to other childhood psychiatric disorders.

Resting state functional connectivity associated with trait emotional intelligence

Previous neuroimaging studies have suggested that trait emotional intelligence (TEI) is associated with components of the neural network involved in social cognition (SCN) and somatic marker circuitry (SMC). Our study is the first to investigate the association of TEI with resting-state functional connectivity (RSFC) between the key nodes of SCN and SMC [medial prefromtal cortex (mPFC) and bilateral anterior insula (AI), respectively] and other brain regions. We found that (a) the intrapersonal factor of TEI was negatively correlated with RSFC between mPFC and the anterior part of the right dorsolateral prefrontal cortex (DLPFC), (b) the TEI interpersonal factor score was positively correlated with RSFC between mPFC and the lingual gyrus, and (c) total TEI was positively correlated with RSFC between mPFC and the precuneus as well as (d) between the left AI and the middle part of the right DLPFC. Taken together with previous study findings, our findings can be comprehensively understood as neural mechanisms of SCN and SMC components are associated with TEI. In particular, the fluent interaction between SCN's two key nodes (mPFC and precuneus/PCC) [as well as between DMN's two key nodes] is suggested to be crucial for total TEI. Our study also indicated that (a) a clear functional separation between the two key nodes of the two major intrinsic networks, DMN and the task-positive network (mPFC and DLPFC), is important for higher intrapersonal TEI, (b) brain interactions involving vision-related areas (lingual gyrus) and the key node of SCN (mPFC) are important for interpersonal TEI, and (c) control of DLPFC over the key node of SMC (AI) is important for total TEI.

Longitudinal developmental courses in Japanese children with autism spectrum disorder

We followed up 67 children with autistic disorder (AD) and 31 children with pervasive developmental disorder not otherwise specified (PDDNOS) for more than 10 years by reviewing medical records at a clinic for children with developmental disabilities. The participants' data were collected between their first visit to the clinic and the visit at which they applied for basic disability benefits. The standardized IQ scores and autistic symptoms were examined as measures of the children's personal functioning. For environmental factors, we examined the participants' educational placements and work and residential status. Using structural equation modeling, we examined the longitudinal developmental courses of AD and PDDNOS. Participants diagnosed with AD consistently showed lower IQ and more severe autistic symptoms than those diagnosed with PDDNOS. Relationships between personal functioning and environmental factors differed between the two groups. AD and PDDNOS are heterogeneous, so they must be treated differently to improve children's prognoses.

Sensorimotor integration and psychopathology: motor control abnormalities related to psychiatric disorders

OBJECTIVES

Recent evidence is reviewed to examine relationships among sensorimotor and cognitive aspects in some important psychiatry disorders. This study reviews the theoretical models in the context of sensorimotor integration and the abnormalities reported in the most common psychiatric disorders, such as Alzheimer's disease, autism spectrum disorder and squizophrenia.

METHODS

The bibliographical search used Pubmed/Medline, ISI Web of Knowledge, Cochrane data base and Scielo databases. The terms chosen for the search were: Alzheimer's disease, AD, autism spectrum disorder, and Squizophrenia in combination with sensorimotor integration. Fifty articles published in English and were selected conducted from 1989 up to 2010.

RESULTS

We found that the sensorimotor integration process plays a relevant role in elementary mechanisms involved in occurrence of abnormalities in most common psychiatric disorders, participating in the acquisition of abilities that have as critical factor the coupling of different sensory data which will constitute the basis of elaboration of consciously goal-directed motor outputs. Whether these disorders are associated with an abnormal peripheral sensory input or defective central processing is still unclear, but some studies support a central mechanism.

CONCLUSION

Sensorimotor integration seems to play a significant role in the disturbances of motor control, like deficits in the feedforward mechanism, typically seen in AD, autistic and squizophrenic patients.

Do Apparent Overlaps between Schizophrenia and Autistic Spectrum Disorders Reflect Superficial Similarities or Etiological Commonalities?

STUDY BACKGROUND: Schizophrenia and autism are both neurodevelopmental disorders that were once considered to be the same disorder expressed in different developmental periods. Although they were separated diagnostically about 40 years ago, they share several clinical and possibly, etiological features. This paper reviews overlaps in four domains of function to consider the issue of whether these similarities are sporadic and likely to represent superficial similarities, or whether the disorders are more likely to share some features in common. METHODS: Representative areas of function were reviewed and compared for aspects of cognition (nonverbal reasoning, memory and language), social function (orienting/joint attention, eye contact and theory of mind), brain function (structural differences) and genetics. To facilitate comparisons with schizophrenia, a focus on high functioning autism/Asperger's disorder was utilized, particularly in the sections on cognition and social function. RESULTS: Significant similarities (and differences) characterized comparisons in each domain. CONCLUSIONS: Disturbed function in similar clinical (in cognition and social function), neurobiological (brain volumes) and genetic (e.g., involvement of the same genes or chromosomal locations) domains in autism and schizophrenia supports the hypothesis that while they are distinct disorders, they are not entirely unique. Additional studies of similarities and differences between them may thus shed light on common etiological mechanisms and hopefully, facilitate the development of novel treatment targets.

Cooperation and heterogeneity of the autistic mind

Individuals with autism spectrum conditions (ASCs) have a core difficulty in recursively inferring the intentions of others. The precise cognitive dysfunctions that determine the heterogeneity at the heart of this spectrum, however, remains unclear. Furthermore, it remains possible that impairment in social interaction is not a fundamental deficit but a reflection of deficits in distinct cognitive processes. To better understand heterogeneity within ASCs, we employed a game-theoretic approach to characterize unobservable computational processes implicit in social interactions. Using a social hunting game with autistic adults, we found that a selective difficulty representing the level of strategic sophistication of others, namely inferring others' mindreading strategy, specifically predicts symptom severity. In contrast, a reduced ability in iterative planning was predicted by overall intellectual level. Our findings provide the first quantitative approach that can reveal the underlying computational dysfunctions that generate the autistic "spectrum."

Neuropsychological profile of autism and the broad autism phenotype

CONTEXT

Multiple articles describe a constellation of language, personality, and social-behavioral features present in relatives that mirror the symptom domains of autism, but are much milder in expression. Studies of this broad autism phenotype (BAP) may provide a potentially important complementary approach for detecting the genes causing autism and defining associated neural circuitry by identifying more refined phenotypes that can be measured quantitatively in both affected and unaffected individuals and that are tied to functioning in particular regions of the brain.

OBJECTIVE

To gain insight into neuropsychological features that index genetic liability to autism.

DESIGN

Case-control study.

SETTING

The general community.

PARTICIPANTS

Thirty-eight high-functioning individuals with autism and parents of autistic individuals, both with and without the BAP (n = 83), as well as control individuals.

MAIN OUTCOME MEASURES

A comprehensive battery of neuropsychological tasks assessing social cognition, executive function, and global vs local processing strategies (central coherence).

RESULTS

Both individuals with autism and parents with the BAP differed from controls on measures of social cognition, with performance in the other 2 domains being more similar to controls.

CONCLUSIONS

Data suggest that the social cognitive domain may be an important target for linking phenotype to cognitive process to brain structure in autism and may ultimately provide insight into the genes involved in autism.

Behavioral effects of omega-3 fatty acid supplementation in young adults with severe autism: an open label study

BACKGROUND

Pilot findings seem to suggest a potential beneficial effect of omega-3 fatty acid (FA) supplementation on behavioral alterations in children with autism. However, data on the potential benefits of omega-3 supplements in young adults with severe autism are lacking. In the present study, we sought to explore this issue in an open label study.

METHODS

Nineteen young adults with severe autism (CARS >40), aged 18-40 years, received two fish oil capsules per day [0.93 g of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) plus 5 mg of vitamin E to avoid lipid peroxidation] for 6 weeks. Subjects were assessed with an ad hoc caregiver questionnaire, the Rossago Behavioral Checklist, for the assessment of behavioral anomalies.

RESULTS

No significant improvements were observed with regard to the severity and frequency of problematic behaviors either during the active treatment period or during the post-treatment 6-week observation period. Moreover, no effect on the number of episodes and severity of behavior aberrations was observed.

CONCLUSIONS

Our negative findings do not point toward a major effect of omega-3 FA supplementation on behavioral abnormalities in adults with severe autism. Further studies on larger sample sizes are warranted to shed more light on this important issue.