1. Benevides TW, Lane SJ. {{A Review of Cardiac Autonomic Measures: Considerations for Examination of Physiological Response in Children with Autism Spectrum Disorder}}. {J Autism Dev Disord}. 2013.
The autonomic nervous system (ANS) is responsible for multiple physiological responses, and dysfunction of this system is often hypothesized as contributing to cognitive, affective, and behavioral responses in children. Research suggests that examination of ANS activity may provide insight into behavioral dysregulation in children with autism spectrum disorders (ASD), however, there is wide variability in samples, methods, and measures reported. The purpose of this review is to describe frequently reported cardiac ANS measures; discuss theoretical models linking ANS measures with neurological structures; and synthesize pediatric literature using ANS measures on typical and ASD samples. Such a synthesis will provide researchers with a foundation for the use of ANS cardiac methods and measures in ASD research.
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2. Goodbourn PT, Bosten JM, Bargary G, Hogg RE, Lawrance-Owen AJ, Mollon JD. {{Variants in the 1q21 risk region are associated with a visual endophenotype of autism and schizophrenia}}. {Genes Brain Behav}. 2013.
Deficits in sensitivity to visual stimuli of low spatial frequency and high temporal frequency (so-called frequency-doubled gratings) have been demonstrated both in schizophrenia and in autism spectrum disorder (ASD). Such basic perceptual functions are ideal candidates for molecular genetic study, because the underlying neural mechanisms are well characterized; but they have sometimes been overlooked in favor of cognitive and neurophysiological endophenotypes, for which neural substrates are often unknown. We report here a genome-wide association study (GWAS) of a basic visual endophenotype associated with psychological disorder. Sensitivity to frequency-doubled gratings was measured in 1060 healthy young adults, and analyzed for association with genotype using linear regression at 642,758 single-nucleotide polymorphism (SNP) markers. A significant association (P = 7.9 x 10-9 ) was found with the SNP marker rs1797052, situated in the 5′-untranslated region of PDZK1; each additional copy of the minor allele was associated with an increase in sensitivity equivalent to more than half a standard deviation. A permutation procedure, which accounts for multiple testing, showed that the association was significant at the alpha = .005 level. The region on chromosome 1q21.1 surrounding PDZK1 is an established susceptibility locus both for schizophrenia and for ASD, mirroring the common association of the visual endophenotype with the two disorders. PDZK1 interacts with NMDA receptors and neuroligins, which have been implicated in the etiologies of schizophrenia and ASD. These findings suggest that perceptual abnormalities observed in two different disorders may be linked by common genetic elements.
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3. Kovac J, Macedoni Luksic M, Trebusak Podkrajsek K, Klancar G, Battelino T. {{Rare Single Nucleotide Polymorphisms in the Regulatory Regions of the Superoxide Dismutase Genes in Autism Spectrum Disorder}}. {Autism Res}. 2013.
Oxidative stress is suspected to be one of the several contributing factors in the etiology of autism spectrum disorder (ASD). We analyzed genes of the superoxide dismutase family (SOD1, SOD2, and SOD3) that are part of a major antioxidative stress system in human in order to detect the genetic variants contributing to the development of ASD. Using the optimized high-resolution melting (HRM) analysis, we identified two rare single nucleotide polymorphisms (SNPs) associated with the etiology of ASD. Both are located in the superoxide dismutase 1 (SOD1) gene and have a minor allele frequency in healthy population approximately 5%. The SNP c.239 + 34A>C (rs2234694) and SNP g.3341C>G (rs36233090) were detected with an odds ratio of 2.65 and P < 0.01. Both are located in the noncoding potentially regulatory regions of the SOD1 gene. This adds to the importance of rare SNPs in the etiology of complex diseases as well as to the importance of noncoding genetic variants analysis with a potential influence on the regulation of gene expression. Autism Res 2013, : -. (c) 2013 International Society for Autism Research, Wiley Periodicals, Inc.
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4. Lopez B. {{Beyond Modularisation: The Need of a Socio-Neuro-Constructionist Model of Autism}}. {J Autism Dev Disord}. 2013.
Autism is a developmental disorder defined by social and communication impairments. Current theoretical approaches and research studies however conceptualise autism as both static and independent from the social context in which it develops. Two lines of research stand out from this general trend. First, research from the neuroconstructivist approach of Karmiloff-Smith (Hum Brain Mapp 31:934-941, 2010) aims to establish developmental trajectories of cognitive impairments in autism over time. Second, studies from intersubjective approaches such as that of Hobson (The cradle of thought, Macmillan, London, 2002) focus on the influence of emotional engagement in cognitive impairments. Although these two lines of research have made an invaluable contribution towards our understanding of autism, both offer only partial explanations: Intersubjective approaches fail to provide a developmental perspective and the neuroconstructivist model neglects the role of the social context. This paper argues that the nature of autism demands the theoretical and methodological integration of these two approaches so that developmental and social aspects are investigated in tandem.
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5. Luck AN, Bobst CE, Kaltashov IA, Mason AB. {{Human serum transferrin: Is there a link between autism, high oxalate and iron deficiency anemia?}}. {Biochemistry}. 2013.
It has been previously suggested that high amounts of oxalate in plasma could play a role in autism by binding to the bilobal iron transport protein transferrin (hTF) thereby interfering with iron metabolism by inhibiting iron delivery to cells. By examining the effect of the substitution of oxalate for the physiologically utilized synergistic carbonate anion in each lobe of hTF we sought to provide a molecular basis for or against such a role. Our work clearly shows both qualitatively (6 M urea gels) and quantitatively (kinetic analysis by stop flow spectrofluorimetry) that the presence of oxalate in place of carbonate in each binding site of hTF does indeed greatly interfere with iron removal from each lobe (both in the absence and presence of the specific hTF receptor). However, we also clearly demonstrate that once the iron is bound within each lobe of hTF, neither anion can displace the other. Additionally, as verified by urea gels and electrospray mass spectrometry, formation of completely homogeneous hTF-anion complexes requires that all iron must first be removed and hTF then reloaded with iron in the presence of either carbonate or oxalate. Of significance, experiments described herein show that carbonate is the preferred binding partner, i.e., even if an equal amount of each anion is available during the iron loading process the hTF-carbonate complex is formed.
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6. Maximo JO, Keown CL, Nair A, Muller RA. {{Approaches to local connectivity in autism using resting state functional connectivity MRI}}. {Front Hum Neurosci}. 2013; 7: 605.
While the literature on aberrant long-distance connectivity in autism spectrum disorder (ASD) has grown fast over the past decade, little is known about local connectivity. We used regional homogeneity and local density approaches at different spatial scales to examine local connectivity in 29 children and adolescents with ASD and 29 matched typically developing participants, using resting state functional magnetic resonance imaging data. Across a total of 12 analysis pipelines, the gross pattern of between-group findings was overall stable, with local overconnectivity in the ASD group in occipital and posterior temporal regions and underconnectivity in middle/posterior cingulate, and medial prefrontal regions. This general pattern was confirmed in secondary analyses for low-motion subsamples (n = 20 per group), in which time series segments with >0.25 mm head motion were censored, as well as in an analysis including global signal regression. Local overconnectivity in visual regions appears consistent with preference for local over global visual processing previously reported in ASD, whereas cingulate and medial frontal underconnectivity may relate to aberrant function within the default mode network.
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7. Moyal WN, Lord C, Walkup JT. {{Quality of Life in Children and Adolescents with Autism Spectrum Disorders: What Is Known About the Effects of Pharmacotherapy?}}. {Paediatr Drugs}. 2013.
A diagnosis of autistic spectrum disorder (ASD), now estimated to affect one in 88 children, requires deficits in social communication and interactions, and restricted interests and/or repetitive behaviors. Almost all children with ASD have deficits in adaptive skills, many have intellectual disability, and others have co-occurring psychiatric disorders or symptoms. Thus, this complex disorder has shown to have a substantial impact on patients’ quality of life (QoL) and that of their families. Medication treatment is considered by clinicians and families to address problems with functioning due to psychiatric problems, and, as such, one-third of children and adolescents with ASD take at least one psychotropic medication and many use complementary and alternative medicine. This paper reviews what is known about the benefits and risks of psychotropic medications on the QoL of children with ASD. Although scarce, there are studies of psychiatric medications in autistic patients that include QoL measures, such as the pediatric studies of aripiprazole for irritability and one adult study of oxytocin. The aripiprazole study showed a positive effect on QoL in treated patients, as did the oxytocin study. Several other psychotropic medications are used in the treatment of children with ASD, and although information is available on the risks and benefits of each, we do not have specific data on the QoL impact of these medications. The aripiprazole and oxytocin studies exemplify how researchers can include QoL measures and use this information to guide clinicians. Additionally, we will recommend areas of further study in pharmacotherapy and QoL research in the context of treating children with ASD.
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8. Robertson CE, Kravitz DJ, Freyberg J, Baron-Cohen S, Baker CI. {{Slower rate of binocular rivalry in autism}}. {J Neurosci}. 2013; 33(43): 16983-91.
An imbalance between cortical excitation and inhibition is a central component of many models of autistic neurobiology. We tested a potential behavioral footprint of this proposed imbalance using binocular rivalry, a visual phenomenon in which perceptual experience is thought to mirror the push and pull of excitatory and inhibitory cortical dynamics. In binocular rivalry, two monocularly presented images compete, leading to a percept that alternates between them. In a series of trials, we presented separate images of objects (e.g., a baseball and a broccoli) to each eye using a mirror stereoscope and asked human participants with autism and matched control subjects to continuously report which object they perceived, or whether they perceived a mixed percept. Individuals with autism demonstrated a slower rate of binocular rivalry alternations than matched control subjects, with longer durations of mixed percepts and an increased likelihood to revert to the previously perceived object when exiting a mixed percept. Critically, each of these findings was highly predictive of clinical measures of autistic symptomatology. Control « playback » experiments demonstrated that differences in neither response latencies nor response criteria could account for the atypical dynamics of binocular rivalry we observed in autistic spectrum conditions. Overall, these results may provide an index of atypical cortical dynamics that may underlie both the social and nonsocial symptoms of autism.
