1. Doll CA, Vita DJ, Broadie K. {{Fragile X Mental Retardation Protein Requirements in Activity-Dependent Critical Period Neural Circuit Refinement}}. {Curr Biol};2017 (Aug 07);27(15):2318-2330.e2313.
Activity-dependent synaptic remodeling occurs during early-use critical periods, when naive juveniles experience sensory input. Fragile X mental retardation protein (FMRP) sculpts synaptic refinement in an activity sensor mechanism based on sensory cues, with FMRP loss causing the most common heritable autism spectrum disorder (ASD), fragile X syndrome (FXS). In the well-mapped Drosophila olfactory circuitry, projection neurons (PNs) relay peripheral sensory information to the central brain mushroom body (MB) learning/memory center. FMRP-null PNs reduce synaptic branching and enlarge boutons, with ultrastructural and synaptic reconstitution MB connectivity defects. Critical period activity modulation via odorant stimuli, optogenetics, and transgenic tetanus toxin neurotransmission block show that elevated PN activity phenocopies FMRP-null defects, whereas PN silencing causes opposing changes. FMRP-null PNs lose activity-dependent synaptic modulation, with impairments restricted to the critical period. We conclude that FMRP is absolutely required for experience-dependent changes in synaptic connectivity during the developmental critical period of neural circuit optimization for sensory input.
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2. Duan X, Chen H, He C, Long Z, Guo X, Zhou Y, Uddin LQ, Chen H. {{Resting-state functional under-connectivity within and between large-scale cortical networks across three low-frequency bands in adolescents with autism}}. {Prog Neuropsychopharmacol Biol Psychiatry};2017 (Aug 02)
Although evidence is accumulating that autism spectrum disorder (ASD) is associated with disruption of functional connections between and within brain networks, it remains largely unknown whether these abnormalities are related to specific frequency bands. To address this question, network contingency analysis was performed on brain functional connectomes obtained from 213 adolescent participants across nine sites in the Autism Brain Imaging Data Exchange (ABIDE) multisite sample, to determine the disrupted connections between and within seven major cortical networks in adolescents with ASD at Slow-5, Slow-4 and Slow-3 frequency bands and further assess whether the aberrant intra- and inter-network connectivity varied as a function of ASD symptoms. Overall under-connectivity within and between large-scale intrinsic networks in ASD was revealed across the three frequency bands. Specifically, decreased connectivity strength within the default mode network (DMN), between DMN and visual network (VN), ventral attention network (VAN), and between dorsal attention network (DAN) and VAN was observed in the lower frequency band (slow-5, slow-4), while decreased connectivity between limbic network (LN) and frontal-parietal network (FPN) was observed in the higher frequency band (slow-3). Furthermore, weaker connectivity within and between specific networks correlated with poorer communication and social interaction skills in the slow-5 band, uniquely. These results demonstrate intrinsic under-connectivity within and between multiple brain networks within predefined frequency bands in ASD, suggesting that frequency-related properties underlie abnormal brain network organization in the disorder.
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3. Harada K, Yamamoto M, Konishi Y, Koyano K, Takahashi S, Namba M, Kusaka T. {{Hypoplastic hippocampus in atypical Rett syndrome with a novel FOXG1 mutation}}. {Brain Dev};2017 (Aug 03)
The forkhead box G1 (FOXG1) gene encodes a brain-specific transcription factor and is associated with a congenital variant of atypical Rett syndrome (RTT); several FOXG1 mutations have been identified. The congenital variant of RTT shows a hypoplastic corpus callosum, delayed myelination, and frontal and temporal atrophy. Although no report has described a hippocampal abnormality in humans, the current study suggests that FOXG1 also regulates neurogenesis in the postnatal hippocampus. In the present case, severe developmental delay was observed in a patient with a congenital variant of RTT from about 4months, in conjunction with acquired microcephaly, hypotonia, limited motor function, absent purposeful hand use, and repetitive jerky movements of the upper limbs. A novel missense mutation was identified in FOXG1 on gene analysis (c. 569T>A, p. Ile190Asn). The patient showed not only the typical cerebral abnormalities of a congenital variant of RTT, but also a hypoplastic hippocampus. This novel mutation and cerebral findings may provide new insights into the pathophysiology of the congenital variant of RTT.
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4. Kuhfeld M, Sturm A. {{An Examination of the Precision of the Autism Diagnostic Observation Schedule Using Item Response Theory}}. {Psychol Assess};2017 (Aug 07)
The current study examined the reliability of the Autism Diagnostic Observation Schedule (ADOS) across the continuum of severity of autism spectrum disorder (ASD) core deficits. Modules 3 and 4 of the ADOS assess the deficits of ASD in 2 core domains (Social Affect and Restrictive and Repetitive Behaviors [RRB]) among verbally fluent children, adolescents, and adults, and ADOS diagnostic classification of ASD is based on a total score that combines the 2 domains. Currently, the total and domain scores are calculated using only a subset of the administered items. This study used an item response theory (IRT) approach to examine whether scores from the ADOS Modules 3 and 4 item sets under the revised scoring algorithm provide adequate reliability around the diagnostic threshold of the total score, as well as across the hypothesized continuum of the Social Affect and RRB domains. Furthermore, the present study examined whether the reliability of the ASD domains measured by the ADOS is improved by incorporating items that are collected but not included in the current diagnostic algorithm. Measurement precision was estimated using IRT models, which allow for an examination of reliability across a continuum of ASD domain severity. Results suggest that although the ADOS Modules 3 and 4 are reliable at the diagnostic threshold using only the scoring algorithm items, adding additional items can improve the reliability of scores at moderately low and moderately high levels of ASD severity. However, even with additional items, the ADOS Modules 3 and 4 do not allow for adequately reliable measurement of restrictive and repetitive behaviors. (PsycINFO Database Record
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5. Saito A, Stickley A, Haraguchi H, Takahashi H, Ishitobi M, Kamio Y. {{Association Between Autistic Traits in Preschool Children and Later Emotional/Behavioral Outcomes}}. {J Autism Dev Disord};2017 (Aug 07)
Although children with a greater number of autistic traits are likely to have other mental health problems, research on the association between earlier autistic traits in preschool children and later emotional/behavioral outcomes is scarce. Using data from 189 Japanese community-based children, this study examined whether autistic traits at age 5 were related to emotional/behavioral outcomes at age 7. The results showed that prior autistic traits were subsequently associated with all emotional/behavioral domains. After controlling for baseline emotional/behavioral scores autistic traits continued to predict later emotional symptoms and peer problems. This study highlights that in addition to clinical ASD, it is also important to focus on subthreshold autistic traits in preschool children for better subsequent emotional/behavioral outcomes.
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6. Schmidt RJ, Schroeder DI, Crary-Dooley FK, Barkoski JM, Tancredi DJ, Walker CK, Ozonoff S, Hertz-Picciotto I, LaSalle JM. {{Self-reported pregnancy exposures and placental DNA methylation in the MARBLES prospective autism sibling study}}. {Environ Epigenet};2016 (Dec);2(4)
Human placenta is a fetal-derived tissue that offers a unique sample of epigenetic and environmental exposures present in utero. In the MARBLES prospective pregnancy study of high-risk younger siblings of children with autism spectrum disorder (ASD), pregnancy and environmental factors collected by maternal interviews were examined as predictors of placental DNA methylation, including partially methylated domains (PMDs), an embryonic feature of the placental methylome. DNA methylation data from MethylC-seq analysis of 47 placentas of children clinically diagnosed at 3 years with ASD or typical development using standardized assessments were examined in relation to: child’s gestational age, birth-weight, and diagnosis; maternal pre-pregnancy body mass index, smoking, education, parity, height, prenatal vitamin and folate intake; home ownership; pesticides professionally applied to lawns or gardens or inside homes, pet flea/tick pouches, collars, or soaps/shampoos used in the 3 months prior to or during pregnancy. Sequencing run, order, and coverage, and child race and sex were considered as potential confounders. Akaike information criterion was used to select the most parsimonious among candidate models. Final prediction models used sandwich estimators to produce homoscadisticity-robust estimates of the 95% confidence interval (CI) and P-values controlled the false discovery rate at 5%. The strongest, most robust associations were between pesticides professionally applied outside the home and higher average methylation over PMDs [0.45 (95% CI 0.17, 0.72), P = 0.03] and a reduced proportion of the genome in PMDs [-0.42 (95% CI – 0.67 to -0.17), P = 0.03]. Pesticide exposures could alter placental DNA methylation more than other factors.
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7. Sotoodeh MS, Arabameri E, Panahibakhsh M, Kheiroddin F, Mirdoozandeh H, Ghanizadeh A. {{Effectiveness of yoga training program on the severity of autism}}. {Complement Ther Clin Pract};2017 (Aug);28:47-53.
This study examines the effect of yoga training program (YTP) on the severity of autism in children with High Function Autism (HFA). Twenty-nine children aged 7 to 15 (mean = 11.22, SD = 2.91) years were randomly allocated to either yoga or control group. The participants in the yoga group received an 8-week (24-session) Yoga Training Program (YTP). Parents or caregivers of participants completed autism treatment evaluation checklist (ATEC) at baseline and the end of the intervention. The results of the analysis showed that there were significant differences between the two groups with regards to all ATEC sub-scores except ATEC I (speech/language/communication). This study provides support for the implementation of a yoga training program and identifies specific procedural enhancements to reduce the severity of symptoms in children with autism.
