Pubmed du 02/06/12

Pubmed du jour

2012-06-02 12:03:50

1. Fiebelkorn IC, Foxe JJ, McCourt ME, Dumas KN, Molholm S. {{Atypical category processing and hemispheric asymmetries in high-functioning children with autism: Revealed through high-density EEG mapping}}. {Cortex};2012 (May 3)

Behavioral evidence for an impaired ability to group objects based on similar physical or semantic properties in autism spectrum disorders (ASD) has been mixed. Here, we recorded brain activity from high-functioning children with ASD as they completed a visual-target detection task. We then assessed the extent to which object-based selective attention automatically generalized from targets to non-target exemplars from the same well-known object class (e.g., dogs). Our results provide clear electrophysiological evidence that children with ASD (N = 17, aged 8-13 years) process the similarity between targets (e.g., a specific dog) and same-category non-targets (SCNT) (e.g., another dog) to a lesser extent than do their typically developing (TD) peers (N = 21). A closer examination of the data revealed striking hemispheric asymmetries that were specific to the ASD group. These findings align with mounting evidence in the autism literature of anatomic underconnectivity between the cerebral hemispheres. Years of research in individuals with TD have demonstrated that the left hemisphere (LH) is specialized toward processing local (or featural) stimulus properties and the right hemisphere (RH) toward processing global (or configural) stimulus properties. We therefore propose a model where a lack of communication between the hemispheres in ASD, combined with typical hemispheric specialization, is a root cause for impaired categorization and the oft-observed bias to process local over global stimulus properties.

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2. Harrison C. {{Neurodevelopmental disorders: Glutamate blockers show benefit in models of autism spectrum disorders}}. {Nat Rev Drug Discov};2012;11(6):440-441.

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3. Stankovic M, Lakic A, Ilic N. {{Autism and autistic spectrum disorders in the context of new DSM-V classification, and clinical and epidemiological data}}. {Srp Arh Celok Lek};2012 (Mar-Apr);140(3-4):236-243.

Autism is one of disorders from the autism spectrum, besides Asperger syndrome, atypical autism and pervasive developmental disorder not otherwise specified. They are classified as mental disorders as being manifested by a wide range of cognitive, emotional and neurobehavioural abnormalities. Key categorical characteristics of the disorder are clear impairments of the development of the child’s socialisation, understanding and production of verbal and non-verbal communication and restricted and repetitive patterns of behaviour. Demarcation boundaries are not clear, neither within the very group of the disorders from the autistic spectrum, nor with respect to the autistic behavioural features in the general population. For this reason, the term spectrum points out the significance of the dimensional assessment of autistic disorders, which will most likely be the basis of the new diagnostic classification of the disorders belonging to the current group of pervasive developmental disorders in the new DSM-V classification. The understanding, as well as the prevalence of the autistic spectrum disorders has changed drastically in the last four decades. From the previous 4 per 10,000 people, today’s prevalence estimates range from 0.6 to around 1%, and the increase of prevalence cannot be explained solely by better recognition on the part of experts and parents or by wider diagnostic criteria. The general conclusion is that the autistic spectrum disorders are no longer rare conditions and that the approach aimed at acknowledging the warning that this is an urgent public health problem is completely justified.

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4. Vishnu Rekha C, Arangannal P, Shahed H. {{Oral health status of children with autistic disorder in Chennai}}. {Eur Arch Paediatr Dent};2012 (Jun);13(3):126-131.

AIM: To assess the oral health status of autistic children in Chennai. DESIGN and METHODS: Oral health status was assessed for 483 children with autism, solicited from special education schools, autistic child centres and therapy centres. Conditions assessed were plaque accumulation, gingival health, dental caries, malocclusion, developmental anomalies, oral injuries and restorations. STATISTICS: Chi-square and Fisher’s exact tests of significance were used to compare groups. Proportions test was used to compare the significance of the parameters between boys and girls. RESULTS: Autistic children with primary dentition showed significantly higher incidence of dental caries (24%), when compared to other oral conditions. Children with mixed dentition had more gingivitis (50%) and children with permanent dentition had more gingivitis (48.96%) and malocclusion (71.15%). All the oral conditions were seen more in boys than girls. CONCLUSION: Autistic children have significantly poor oral hygiene and higher incidence of malocclusion and dental caries when compared to other oral conditions.

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5. Xu S, Poidevin M, Han E, Bi J, Jin P. {{Circadian rhythm-dependent alterations of gene expression in Drosophila brain lacking fragile x mental retardation protein}}. {PLoS One};2012;7(5):e37937.

Fragile X syndrome is caused by the loss of the FMR1 gene product, fragile X mental retardation protein (FMRP). The loss of FMRP leads to altered circadian rhythm behaviors in both mouse and Drosophila; however, the molecular mechanism behind this phenomenon remains elusive. Here we performed a series of gene expression analyses, including of both mRNAs and microRNAs (miRNAs), and identified a number of mRNAs and miRNAs (miRNA-1 and miRNA-281) with circadian rhythm-dependent altered expression in dfmr1 mutant flies. Identification of these RNAs lays the foundation for future investigations of the molecular pathway(s) underlying the altered circadian rhythms associated with loss of dFmr1.

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