Pubmed du 14/02/14

Pubmed du jour

2014-02-14 12:03:50

1. Dincel N, Unalp A, Kutlu A, Ozturk A, Uran N, Ulusoy S. {{Serum nerve growth factor levels in autistic children in Turkish population: A preliminary study}}. {Indian J Med Res};2013 (Dec);138(6):900-903.

Background & objectives: It has been hypothesized that abnormal levels of serum nerve growth factor (NGF) may represent a serological marker for autistic children who may develop cognitive impairment, regression and finally epilepsy. The objective of this preliminary study was to measure serum NGF concentrations of autistic children and compare these levels with those of healthy children. Methods: Consecutive children who were referred to the Paediatric Neurology and Child Psychiatry Policlinics of Dr. Behcet Uz Child Disease and Pediatric Surgery Training and Research Hospital, Turkey between February and September 2008 were included in the study. Serum samples were analyzed for NGF levels using ChemiKine NGF Sandwich ELISA Kit. Comparisons between the study and the control groups were made using student’s t test and Chi-square test. Results: Forty-nine autistic children and an equal number of healthy children (control group) were included in the study. No significant difference was found between the study and the control groups in terms of children’s age, while number of boys was significantly higher (P<0.05) in the study group. Average serum NGF concentrations were 46.94 +/- 51.40 and 32.94 +/- 12.48 pg/ml in the study and control group, respectively. Serum NGF concentrations were significantly higher (P<0.05) in the study group compared with the control group. Interpretation & conclusions: Our preliminary findings show that enhanced serum NGF concentration may be used as a potential diagnostic tool in autism, however, further studies including a large number of patients are required to confirm the findings.

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2. Jameel L, Vyas K, Bellesi G, Roberts V, Channon S. {{Going ‘Above and Beyond’: Are Those High in Autistic Traits Less Pro-social?}}. {J Autism Dev Disord};2014 (Feb 13)
Few studies have explored how the cognitive differences associated with autistic spectrum disorder translate into everyday social behaviour. This study investigated pro-social behaviour in students scoring high and low on the autism-spectrum quotient (AQ), using a novel scenario task: ‘Above and Beyond’. Each scenario involved an opportunity to behave pro-socially, and thus required balancing the needs of a character against participants’ own interests. High AQ participants both generated responses and selected courses of action that were less pro-social than those of the low AQ group. For actions of low pro-social value they gave higher self-satisfaction ratings; conversely, they gave lower self-satisfaction ratings for high pro-social actions. The implications for everyday functioning are considered for those with high autistic traits.

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3. Kas MJ, Modi ME, Saxe MD, Smith DG. {{Advancing the discovery of medications for autism spectrum disorder using new technologies to reveal social brain circuitry in rodents}}. {Psychopharmacology (Berl)};2014 (Feb 13)
INTRODUCTION: Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition characterized by core differences and impairments in social behavioral functioning. There are no approved medications for improving social cognition and behavior in ASD, and the underlying mechanisms needed to discover safer, more effective medications are unclear. DISCUSSION: In this review, we diagram the basic neurocircuitry governing social behaviors in order to provide a neurobiological framework for the origins of the core social behavioral symptoms of ASD. In addition, we discuss recent technological innovations in research tools that provide unprecedented observation of cellular morphology and activity deep within the intact brain and permit the precise control of discrete brain regions and specific cell types at distinct developmental stages. CONCLUSIONS: The use of new technologies to reveal the neural circuits underlying social behavioral impairments associated with ASD is advancing our understanding of the brain changes underlying ASD and enabling the discovery of novel and effective therapeutic interventions.

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4. Lanning BA, Baier ME, Ivey-Hatz J, Krenek N, Tubbs JD. {{Effects of Equine Assisted Activities on Autism Spectrum Disorder}}. {J Autism Dev Disord};2014 (Feb 14)
Quality of life assessments were used in this study to determine the behavioral changes of children diagnosed with autism spectrum disorder (ASD) who participated in equine assisted activities. Behavioral changes of children with ASD participating in 9 weeks of equines assisted activities (EAA) (N = 10) were compared to behavioral changes of children who participated in a non-equine intervention (N = 8). Parents noted significant improvements in their child’s physical, emotional and social functioning following the first 6 weeks of EAA. The children participating in the non-equine program also demonstrated improvement in behavior, but to a lesser degree. The favorable outcome of this study lends support for continuation of programs utilizing EAA in the treatment of children with ASD.

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5. Lunsky Y, Balogh R, Sullivan WF, Jaakkimainen RL. {{Periodic health examinations for adults with developmental disabilities: Are we doing enough?}}. {Can Fam Physician};2014 (Feb);60(2):109-110.

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6. Martin GN, Daniel N. {{Autism spectrum disorders and chemoreception: dead-end or fruitful avenue of inquiry?}}. {Front Psychol};2014;5:42.

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7. Matsuyoshi D, Kuraguchi K, Tanaka Y, Uchida S, Ashida H, Watanabe K. {{Individual differences in autistic traits predict the perception of direct gaze for males, but not for females}}. {Mol Autism};2014;5(1):12.

Despite the emphasis of autism spectrum disorders as a continuum of atypical social behaviors and the sexual heterogeneity of phenotypic manifestations, whether gaze processing constitutes an autistic endophenotype in both sexes remains unclear. Using the Autism-Spectrum Quotient and a psychophysical approach in a normal population (N = 128), here we demonstrated that individual differences in autistic traits predicted direct-gaze perception for males, but not for females. Our findings suggest that direct-gaze perception may not constitute an autistic endophenotype in both sexes, and highlight the importance of sex differences when considering relationships between autistic traits and behaviors.

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8. Nijmeijer JS, Arias-Vasquez A, Rommelse NN, Altink ME, Buschgens CJ, Fliers EA, Franke B, Minderaa RB, Sergeant JA, Buitelaar JK, Hoekstra PJ, Hartman CA. {{Quantitative Linkage for Autism Spectrum Disorders Symptoms in Attention-Deficit/Hyperactivity Disorder: Significant Locus on Chromosome 7q11}}. {J Autism Dev Disord};2014 (Feb 14)
We studied 261 ADHD probands and 354 of their siblings to assess quantitative trait loci associated with autism spectrum disorder symptoms (as measured by the Children’s Social Behavior Questionnaire (CSBQ)) using a genome-wide linkage approach, followed by locus-wide association analysis. A genome-wide significant locus for the CSBQ subscale addressing social interaction was found on chromosome 7q11, with suggestive signals supporting this locus on three other CSBQ subscales. We identified two other suggestive loci for the CSBQ total scale and individual subscales on chromosomes 4q35 and 7p12. Fine-mapping the significantly linked locus resulted in interesting candidate genes, although their association was not significant after permutation testing.

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9. Oyama G, Umemura A, Shimo Y, Nishikawa N, Nakajima A, Jo T, Nakajima M, Ishii H, Yamada D, Takanashi M, Arai H, Nanba E, Hattori N. {{Posterior Subthalamic Area Deep Brain Stimulation for Fragile X-Associated Tremor/Ataxia Syndrome}}. {Neuromodulation};2014 (Feb 14)

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10. Puts NA, Wodka EL, Tommerdahl M, Mostofsky SH, Edden RA. {{Impaired tactile processing in children with Autism Spectrum Disorder}}. {J Neurophysiol};2014 (Feb 12)
Impaired responses to tactile stimulation are a commonly reported symptom among children with Autism Spectrum Disorder (ASD). Furthermore, impairments in filtering or habituation to tactile input have been described in ASD. This study measured different aspects of tactile processing to investigate atypical touch sensitivity in children with ASD, methodology that has not been previously used in this population. 68 typically developing children (TDC) and 32 children with ASD (ages 8-12) completed vibrotactile tasks assessing: reaction time (RT); static and dynamic detection threshold (DT); amplitude discrimination with and without single-site adaptation; frequency discrimination (FD); and temporal order judgment (TOJ) with and without concurrent stimulation. Children with ASD showed raised static detection thresholds and an absence of the effect of a dynamically increasing sub-threshold stimulus on static detection threshold. Children with ASD also showed poorer amplitude discrimination than TDC, as well as decreased adaptation. There were no significant differences in FD or TOJ between groups. Differences in the effect of dynamic stimulation on DT suggest impaired feed-forward inhibition in autism, which may be linked to poor sensory filtering. Increased baseline amplitude discrimination thresholds in ASD suggest that lateral inhibitory connections are weaker in ASD, and an absence of the effect of adaptation suggests impaired modulation of lateral inhibitory connections in ASD, which may relate to aberrant habituation. These results suggest a functional deficit in the somatosensory inhibitory system in autism. Understanding the specific mechanisms underlying sensory symptoms in autism may allow for more specific therapeutic or drug- targeting in the near future.

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11. Rosenstein MG, Newman TB, Norton ME. {{Re: Does augmentation or induction of labor with oxytocin increase the risk for autism?}}. {Am J Obstet Gynecol};2014 (Feb 14)

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12. Schmitz EA, Banerjee R, Pouw LB, Stockmann L, Rieffe C. {{Better to be equal? Challenges to equality for cognitively able children with autism spectrum disorders in a social decision game}}. {Autism};2014 (Feb 12)
Much controversy surrounds questions about whether humans have an aversion to inequity and how a commitment to equality might play a role in cooperation and other aspects of social interactions. Examining the social decisions of children with autism spectrum disorders provides a fascinating opportunity to explore these issues. Specifically, we evaluated the possibility that children with autism spectrum disorders may be less likely than typically developing children to show a prioritisation of equality. A total of 69 typically developing (mean age 11;6 years) and 57 cognitively able children with autism spectrum disorders (mean age 11;7 years) played a social decision game in which the equality option was pitted against alternatives that varied in instrumental outcomes. Results showed that both groups were more likely to choose the equality option when there was no cost to the self. However, even though children with autism spectrum disorders appeared to view equality as preferable to causing explicit harm to others, they departed from an equality stance when there was an opportunity to increase instrumental gain without any obvious harm to the self or the other. Typically developing children, in contrast, showed similar prioritisation of equality across these contexts. Future research needs to address the question of how differences in the commitment to equality affect children’s social behaviour and relationships in daily life.

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13. Schwarzkopf DS, Anderson EJ, de Haas B, White SJ, Rees G. {{Larger extrastriate population receptive fields in autism spectrum disorders}}. {J Neurosci};2014 (Feb 12);34(7):2713-2724.

Previous behavioral research suggests enhanced local visual processing in individuals with autism spectrum disorders (ASDs). Here we used functional MRI and population receptive field (pRF) analysis to test whether the response selectivity of human visual cortex is atypical in individuals with high-functioning ASDs compared with neurotypical, demographically matched controls. For each voxel, we fitted a pRF model to fMRI signals measured while participants viewed flickering bar stimuli traversing the visual field. In most extrastriate regions, perifoveal pRFs were larger in the ASD group than in controls. We observed no differences in V1 or V3A. Differences in the hemodynamic response function, eye movements, or increased measurement noise could not account for these results; individuals with ASDs showed stronger, more reliable responses to visual stimulation. Interestingly, pRF sizes also correlated with individual differences in autistic traits but there were no correlations with behavioral measures of visual processing. Our findings thus suggest that visual cortex in ASDs is not characterized by sharper spatial selectivity. Instead, we speculate that visual cortical function in ASDs may be characterized by extrastriate cortical hyperexcitability or differential attentional deployment.

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14. Skewes JC, Jegindo EM, Gebauer L. {{Perceptual inference and autistic traits}}. {Autism};2014 (Feb 12)
Autistic people are better at perceiving details. Major theories explain this in terms of bottom-up sensory mechanisms or in terms of top-down cognitive biases. Recently, it has become possible to link these theories within a common framework. This framework assumes that perception is implicit neural inference, combining sensory evidence with prior perceptual knowledge. Within this framework, perceptual differences may occur because of enhanced precision in how sensory evidence is represented or because sensory evidence is weighted much higher than prior perceptual knowledge. In this preliminary study, we compared these models using groups with high and low autistic trait scores (Autism-Spectrum Quotient). We found evidence supporting the cognitive bias model and no evidence for the enhanced sensory precision model.

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15. Sun X, Allison C, Auyeung B, Matthews FE, Norton S, Baron-Cohen S, Brayne C. {{Psychometric Properties of the Mandarin Version of the Childhood Autism Spectrum Test (CAST): An Exploratory Study}}. {J Autism Dev Disord};2014 (Feb 13)
Limited studies have investigated the latent autistic traits in the mainland Chinese population for autism spectrum conditions (ASC). This study explored the psychometric properties of a Mandarin Chinese version of the CAST in a sample consisting of 737 children in mainstream schools and 50 autistic cases. A combination of categorical data factor analysis and item response theory suggested a good-fit model of a two-factor solution for 28 items on the Mandarin CAST including social and communication, and inflexible/stereotyped language and behaviours (Goodness-of-fit indices: RMSEA = 0.029, CFI = 0.957, TLI = 0.950, SRMR = 0.064). The correlation between the two factors was moderate (GFC = 0.425). This study provided evidence for the CAST as a multidimensional measure for ASC screening in a Chinese population and also showed that the symptom manifestation of ASC in Chinese children shares similarity with western populations.

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16. van der Molen MJ, Stam CJ, van der Molen MW. {{Resting-state EEG oscillatory dynamics in fragile x syndrome: abnormal functional connectivity and brain network organization}}. {PLoS One};2014;9(2):e88451.

Disruptions in functional connectivity and dysfunctional brain networks are considered to be a neurological hallmark of neurodevelopmental disorders. Despite the vast literature on functional brain connectivity in typical brain development, surprisingly few attempts have been made to characterize brain network integrity in neurodevelopmental disorders. Here we used resting-state EEG to characterize functional brain connectivity and brain network organization in eight males with fragile X syndrome (FXS) and 12 healthy male controls. Functional connectivity was calculated based on the phase lag index (PLI), a non-linear synchronization index that is less sensitive to the effects of volume conduction. Brain network organization was assessed with graph theoretical analysis. A decrease in global functional connectivity was observed in FXS males for upper alpha and beta frequency bands. For theta oscillations, we found increased connectivity in long-range (fronto-posterior) and short-range (frontal-frontal and posterior-posterior) clusters. Graph theoretical analysis yielded evidence of increased path length in the theta band, suggesting that information transfer between brain regions is particularly impaired for theta oscillations in FXS. These findings are discussed in terms of aberrant maturation of neuronal oscillatory dynamics, resulting in an imbalance in excitatory and inhibitory neuronal circuit activity.

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