1. Beaulieu MA. {{Linking the fragile X mental retardation protein to the lipoxygenase pathway}}. {Med Hypotheses};2013 (Jan 9)
Fragile X mental retardation is caused by the absence of the FMRP (fragile X mental retardation protein) a RNA-binding protein encoded by the Fmr1 gene. Despite the large number of studies about this syndrome, it is still unclear how the absence of FMRP affects the physiology of the nervous system. It has been reported however that the brain of the Fmr1-KO mouse shows altered membrane protein and lipid oxidation. There is also indirect evidence that FMRP may be involved in a negative feedback mechanism with metabotropic glutamate receptors (mGluRs). In this article, we will discuss several lines of evidences which tend to prove that the lipoxygenase pathway might be the missing link between FMRP and mGluRs.
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2. Buckley A, Wingert K, Swedo S, Thurm A, Sato S, Appel S, Rodriguez AJ. {{First night effect analysis in a cohort of young children with autism spectrum disorder}}. {J Clin Sleep Med};2013;9(1):67-70.
STUDY OBJECTIVES: To evaluate for the first night effect (FNE) in a group of young children with autism. DESIGN: Analysis of polysomnographic data from a 2-night sleep laboratory study. SETTING: Clinical Center of the National Institutes of Health. PATIENTS OR PARTICIPANTS: 15 children (aged 2-10 years) with a diagnosis of an ASD. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Polysomnographic analysis showed the presence of a FNE for wake after sleep onset minutes, stage 2, and sleep efficiency, but not for REM sleep parameters or TST. CONCLUSIONS: In this 2-night polysomnographic analysis of sleep stages in young children with autism, we did not find the expected second night increase in total sleep time or REM sleep percentage or a decrease in REM sleep latency. This lack of an FNE for TST and REM parameters suggests that a single-night polysomnogram may be sufficient to evaluate children with an ASD for TST or REM parameters. CITATION: Buckley A; Wingert K; Swedo S; Thurm A; Sato S; Appel S; Rodriguez AJ. First night effect analysis in a cohort of young children with autism spectrum disorder. J Clin Sleep Med 2013;9(1):67-70.
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3. Catarino A, Andrade A, Churches O, Wagner AP, Baron-Cohen S, Ring H. {{Task-related functional connectivity in autism spectrum conditions: an EEG study using wavelet transform coherence}}. {Mol Autism};2013 (Jan 12);4(1):1.
ABSTRACT: BACKGROUND: Autism Spectrum Conditions (ASC) are a set of pervasive neurodevelopmental conditions characterized by a wide range of lifelong signs and symptoms. Recent explanatory models of autism propose abnormal neural connectivity and are supported by studies showing decreased interhemispheric coherence in individuals with ASC. The first aim of this study was to test the hypothesis of reduced interhemispheric coherence in ASC, and secondly to investigate specific effects of task performance on interhemispheric coherence in ASC. METHODS: We analyzed electroencephalography (EEG) data from 15 participants with ASC and 15 typical controls, using Wavelet Transform Coherence (WTC) to calculate interhemispheric coherence during face and chair matching tasks, for EEG frequencies from 5 to 40 Hz and during the first 400 ms post-stimulus onset. RESULTS: Results demonstrate a reduction of interhemispheric coherence in the ASC group, relative to the control group, in both tasks and for all electrode pairs studied. For both tasks, group differences were generally observed after around 150 ms and at frequencies lower than 13 Hz. Regarding within-group task comparisons, while the control group presented differences in interhemispheric coherence between faces and chairs tasks at various electrode pairs (FT7-FT8, TP7-TP8, P7-P8), such differences were only seen for one electrode pair in the ASC group (T7-T8). No significant differences in EEG power spectra were observed between groups. CONCLUSIONS: Interhemispheric coherence is reduced in people with ASC, in a time and frequency specific manner, during visual perception and categorization of both social and inanimate stimuli and this reduction in coherence is widely dispersed across the brain.Results of within-group task comparisons may reflect an impairment in task differentiation in people with ASC relative to typically developing individuals.Overall, the results of this research support the value of WTC in examining the time-frequency microstructure of task-related interhemispheric EEG coherence in people with ASC.
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4. Chawarska K, Macari S, Shic F. {{Decreased Spontaneous Attention to Social Scenes in 6-Month-Old Infants Later Diagnosed with Autism Spectrum Disorders}}. {Biol Psychiatry};2013 (Jan 10)
BACKGROUND: The ability to spontaneously attend to the social overtures and activities of others is essential for the development of social cognition and communication. This ability is critically impaired in toddlers with autism spectrum disorders (ASD); however, it is not clear if prodromal symptoms in this area are already present in the first year of life of those affected by the disorder. METHODS: To examine whether 6-month-old infants later diagnosed with ASD exhibit atypical spontaneous social monitoring skills, visual responses of 67 infants at high-risk and 50 at low-risk for ASD were studied using an eye-tracking task. Based on their clinical presentation in the third year, infants were divided into those with ASD, those exhibiting atypical development, and those developing typically. RESULTS: Compared with the control groups, 6-month-old infants later diagnosed with ASD attended less to the social scene, and when they did look at the scene, they spent less time monitoring the actress in general and her face in particular. Limited attention to the actress and her activities was not accompanied by enhanced attention to objects. CONCLUSIONS: Prodromal symptoms of ASD at 6 months include a diminished ability to attend spontaneously to people and their activities. A limited attentional bias toward people early in development is likely to have a detrimental impact on the specialization of social brain networks and the emergence of social interaction patterns. Further investigation into its underlying mechanisms and role in psychopathology of ASD in the first year is warranted.
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5. Gaigg SB. {{The Interplay between Emotion and Cognition in Autism Spectrum Disorder: Implications for Developmental Theory}}. {Front Integr Neurosci};2012;6:113.
Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that is clinically defined by abnormalities in reciprocal social and communicative behaviors and an inflexible adherence to routinised patterns of thought and behavior. Laboratory studies repeatedly demonstrate that autistic individuals experience difficulties in recognizing and understanding the emotional expressions of others and naturalistic observations show that they use such expressions infrequently and inappropriately to regulate social exchanges. Dominant theories attribute this facet of the ASD phenotype to abnormalities in a social brain network that mediates social-motivational and social-cognitive processes such as face processing, mental state understanding, and empathy. Such theories imply that only emotion related processes relevant to social cognition are compromised in ASD but accumulating evidence suggests that the disorder may be characterized by more widespread anomalies in the domain of emotions. In this review I summarize the relevant literature and argue that the social-emotional characteristics of ASD may be better understood in terms of a disruption in the domain-general interplay between emotion and cognition. More specifically I will suggest that ASD is the developmental consequence of early emerging anomalies in how emotional responses to the environment modulate a wide range of cognitive processes including those that are relevant to navigating the social world.
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6. Goldman S, Greene PE. {{Stereotypies in autism: a video demonstration of their clinical variability}}. {Front Integr Neurosci};2012;6:121.
In autism, stereotypies are frequent and disabling, and whether they correspond to a hyperkinetic movement disorder, a homeostatic response aiming at sensory modulation, or a regulator of arousal remains to be established. So far, it has been challenging to distinguish among these different possibilities, not only because of lack of objective and quantitative means to assess stereotypies, but in our opinion also because of the underappreciated diversity of their clinical presentations. Herein, we illustrate the broad spectrum of stereotypies and demonstrate the usefulness of video-assisted clinical observations of children with autism. The clips presented were extracted from play sessions of 129 children with autism disorder. We conclude that compared to widely used questionnaires and interviews, systematic video observations provide a unique means to classify and score precisely the clinical features of stereotypies. We believe this approach will prove useful to both clinicians and researchers as it offers the level of detail from retrievable images necessary to begin to assess effects of age and treatments on stereotypies, and to embark on the type of investigations required to unravel the physiological basis of motor behaviors in autism.
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7. Jones EJ, Webb SJ, Estes A, Dawson G. {{Rule learning in autism: the role of reward type and social context}}. {Dev Neuropsychol};2013 (Jan);38(1):58-77.
Learning abstract rules is central to social and cognitive development. Across two experiments, we used Delayed Non-Matching to Sample tasks to characterize the longitudinal development and nature of rule-learning impairments in children with Autism Spectrum Disorder (ASD). Results showed that children with ASD consistently experienced more difficulty learning an abstract rule from a discrete physical reward than children with DD. Rule learning was facilitated by the provision of more concrete reinforcement, suggesting an underlying difficulty in forming conceptual connections. Learning abstract rules about social stimuli remained challenging through late childhood, indicating the importance of testing executive functions in both social and non-social contexts.
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8. Kim KC, Kim P, Go HS, Choi CS, Park JH, Kim HJ, Jeon SJ, Dela Pena IC, Han SH, Cheong JH, Ryu JH, Shin CY. {{Male-specific alteration in excitatory postsynaptic development and social interaction in prenatal valproic acid exposure model of autism spectrum disorder}}. {J Neurochem};2013 (Jan 12)
Autism spectrum disorder (ASD) is a pervasive developmental disorder characterized by three main behavioral symptoms including social deficits, impaired communication, and stereotyped and repetitive behaviors. ASD prevalence shows gender bias to male. Prenatal exposure to valproic acid (VPA), a drug used in epilepsy and bipolar disorder, induces autistic symptoms in both human and rodents. As we reported previously, prenatally VPA-exposed animals at E12 showed impairment in social behavior without any overt reproductive toxicity. Social interactions were not significantly different between in male and female rats in control condition. However, VPA-exposed male offspring showed significantly impaired social interaction while female offspring showed only marginal deficits in social interaction. Similar male inclination was observed in hyperactivity behavior induced by VPA. In addition to the ASD-like behavioral phenotype, prenatally VPA-exposed rat offspring shows crooked tail phenotype, which was not different between male and female groups. Both male and female rat showed reduced GABAergic neuronal marker GAD and increased glutamatergic neuronal marker vGluT1 expression. Interestingly, despite of the similar increased expression of vGluT1, postsynaptic marker proteins such as PSD-95 and alpha-CAMKII expression was significantly elevated only in male offspring. Electron microscopy showed increased number of postsynapse in male but not in female at 4weeks of age. These results might suggest that the altered glutamatergic neuronal differentiation leads to deranged postsynaptic maturation only in male offspring prenatally exposed to VPA. Consistent with the increased postsynaptic compartment, VPA-exposed male rats showed higher sensitivity to electric shock than VPA-exposed female rats. These results suggest that prenatally VPA-exposed rats show the male preponderance of ASD-like behaviors including defective social interaction similar to human autistic patients, which might be caused by ectopic increase in glutamatergic synapses in male rats. (c) 2013 International Society for Neurochemistry, J. Neurochem. (2013) 10.1111/jnc.12147.
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9. Kujala T, Lepisto T, Naatanen R. {{The neural basis of aberrant speech and audition in autism spectrum disorders}}. {Neurosci Biobehav Rev};2013 (Jan 10)
Autism spectrum disorders (ASD) are characterized by deficits in communication and social behavior and by narrow interests. Individuals belonging to this spectrum have abnormalities in various aspects of language, ranging from semantic-pragmatic deficits to the absence of speech. They also have aberrant perception, especially in the auditory domain, with both hypo- and hypersensitive features. Neurophysiological approaches with high temporal resolution have given novel insight into the processes underlying perception and language in ASD. Neurophysiological recordings, which are feasible for investigating infants and individuals with no speech, have shown that the representation of and attention to language has an abnormal developmental path in ASD. Even the basic mechanisms for fluent speech perception are degraded at a low level of neural speech analysis. Furthermore, neural correlates of perception and some traits typical of subgroups of individuals on this spectrum have helped in understanding the diversity on this spectrum.
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10. Wang JY, Hessl D, Iwahashi C, Cheung K, Schneider A, Hagerman RJ, Hagerman PJ, Rivera SM. {{Influence of the fragile X mental retardation (FMR1) gene on the brain and working memory in men with normal FMR1 alleles}}. {Neuroimage};2013 (Jan 15);65:288-298.
The fragile X mental retardation 1 (FMR1) gene plays an important role in the development and maintenance of neuronal circuits that are essential for cognitive functioning. We explored the functional linkage(s) among lymphocytic FMR1 gene expression, brain structure, and working memory in healthy adult males. We acquired T1-weighted and diffusion tensor imaging from 37 males (18-80years, mean+/-SD=40.7+/-17.3years) with normal FMR1 alleles and performed genetic and working memory assessments. Brain measurements were obtained from fiber tracts important for working memory (i.e. the arcuate fasciculus, anterior cingulum bundle, inferior longitudinal fasciculus, and the genu and anterior body of the corpus callosum), individual voxels, and whole brain. Both FMR1 mRNA and protein (FMRP) levels exhibited significant associations with brain measurements, with FMRP correlating positively with gray matter volume and white matter structural organization, and FMR1 mRNA negatively with white matter structural organization. The correlation was widespread, impacting rostral white matter and 2 working-memory fiber tracts for FMRP, and all cerebral white matter areas except the fornix and cerebellar peduncles and all 4 fiber tracts for FMR1 mRNA. In addition, the levels of FMR1 mRNA as well as the fiber tracts demonstrated a significant correlation with working memory performance. While FMR1 mRNA exhibited a negative correlation with working memory, fiber tract structural organization showed a positive correlation. These findings suggest that the FMR1 gene is a genetic factor common for both working memory and brain structure, and has implications for our understanding of the transmission of intelligence and brain structure.
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11. Whiteley P, Shattock P, Knivsberg AM, Seim A, Reichelt KL, Todd L, Carr K, Hooper M. {{Gluten- and casein-free dietary intervention for autism spectrum conditions}}. {Front Hum Neurosci};2012;6:344.
Dietary intervention as a tool for maintaining and improving physical health and wellbeing is a widely researched and discussed topic. Speculation that diet may similarly affect mental health and wellbeing particularly in cases of psychiatric and behavioral symptomatology opens up various avenues for potentially improving quality of life. We examine evidence suggestive that a gluten-free (GF), casein-free (CF), or gluten- and casein-free diet (GFCF) can ameliorate core and peripheral symptoms and improve developmental outcome in some cases of autism spectrum conditions. Although not wholly affirmative, the majority of published studies indicate statistically significant positive changes to symptom presentation following dietary intervention. In particular, changes to areas of communication, attention, and hyperactivity are detailed, despite the presence of various methodological shortcomings. Specific characteristics of best- and non-responders to intervention have not been fully elucidated; neither has the precise mode of action for any universal effect outside of known individual cases of food-related co-morbidity. With the publication of controlled medium- and long-term group studies of a gluten- and casein-free diet alongside more consolidated biological findings potentially linked to intervention, the appearance of a possible diet-related autism phenotype seems to be emerging supportive of a positive dietary effect in some cases. Further debate on whether such dietary intervention should form part of best practice guidelines for autism spectrum conditions (ASCs) and onward representative of an autism dietary-sensitive enteropathy is warranted.
