Autism Research最新文献

Emerging evidence highlights widespread alterations in white matter microstructure in autism. Advances in magnetic resonance imaging (MRI) have enabled more precise examinations of these microstructural changes, leading to increased use of quantitative MRI techniques in autism research. This review summarizes the current landscape of these techniques, focusing on methodology, group differences, developmental associations, and regional variations. Following PRISMA guidelines, 34 studies published between 2006 and 2024 that employed advanced MRI techniques were reviewed. These included diffusion MRI signal representations (diffusion kurtosis imaging [DKI] and constrained spherical deconvolution [CSD]) and biophysical models (neurite orientation dispersion and density imaging [NODDI] and white matter tract integrity [WMTI]), as well as relaxometry and magnetization transfer imaging (MTI). CSD and NODDI were the most frequently used, while MTI was the least utilized, with notable variations in acquisition parameters and processing methods across the techniques. Findings suggest relatively consistent lower values of fixel-based analysis measures (CSD) and neurite density index (NODDI) across major white matter regions, while findings from DKI, WMTI, and relaxometry varied. Measures from these techniques were associated with various developmental outcomes, including cognitive, emotional, and social behaviors. Limitations and implications are also discussed.

The hippocampus plays a crucial role in memory and social processing, both of which are impaired in autism spectrum disorder (ASD). Investigating the functional activity of hippocampal subregions can provide valuable insights into their involvement in ASD-related social and behavioral symptoms. This study analyzed hippocampal resting-state functional connectivity (rsFC) in 507 male child participants from the ABIDE dataset (225 ASD, 282 typical controls) and its relation to clinical features. The hippocampus was subdivided into rostral and caudal subregions, and rsFC patterns were compared between groups. Significant group differences were observed in the left caudal, right rostral, and right caudal hippocampus, with enhanced connectivity to widespread cortical and subcortical regions, including visual, motor, parietal, and cerebellar networks. Machine learning using hippocampal rsFC achieved modest classification performance. Clinically, rsFC correlated with core ASD symptoms: social awareness was associated with right caudal connectivity to fusiform and temporal regions, while restricted and repetitive behaviors were linked to distinct rostral–caudal patterns involving frontal, motor, and cerebellar areas. Age of onset showed positive correlations with rsFC across all subregions, with rostral hippocampus engaging socioemotional and motor control networks and caudal hippocampus connecting more strongly to visual and sensorimotor integration regions. These findings demonstrate subregional specificity of hippocampal connectivity in ASD, suggesting distinct anterior–posterior contributions to symptom expression and developmental timing.

The long-term outcomes of regression in autism spectrum disorder (ASD) remain unclear. Previous evidence suggests that autistic individuals with regression have poorer adulthood outcomes across various indices than those without regression. We compared two groups—those with and without regression in ASD—among 168 participants from a population-based birth cohort study. These individuals were born in northern Yokohama, Japan, between 1988 and 1996 and were diagnosed with ASD by age seven. Participants were classified into groups based on real-time records from a community-oriented mass screening system. This study focused on four outcomes: IQ at age five, IQ in adulthood, incidence of epilepsy, and composite social ability score. None of the outcomes showed significant differences between the two groups. The standardized effect size (where a positive value favors the non-regression group) was 0.06 (95% CI: −0.08 to 0.21) for the composite social ability score, −0.16 (95% CI: −0.55 to 0.22) for IQ at age five, and −0.15 (95% CI: −0.62 to 0.33) for IQ in adulthood. The risk ratio of epilepsy in the regression group compared to the non-regression group was 0.59 (95% CI: 0.22 to 1.5). No significant differences were observed in any of the four outcomes between autistic individuals with or without regression. The confidence intervals of the effect sizes indicate that the impact of regression on IQ and psychosocial adaptation in adulthood, if present, is likely to be small to intermediate.

Adolescence is a time of complex social and emotional development when friendships become of particular importance. Previous research has highlighted differences in the social experience of autistic and non-autistic adolescents, as well as that of autistic girls and boys. However, no study has compared the social experiences of autistic and non-autistic adolescents, including gender differences, in a population-representative sample. Using data from the Millennium Cohort Study (MCS), Sweep 6, we investigated differences between autistic (girls n = 111, boys n = 387) and non-autistic (girls n = 5847, boys = 5697) adolescents (mean age = 13.7 years, range = 13–15) regarding self-reports of: (i) having close friends, (ii) time spent with friends, (iii) social support, (iv) social alienation, (v) happiness with friendships, and (vi) having a romantic partner. Autistic adolescents reported having fewer close friends and spending less time with their friends. Autistic boys felt less socially supported than non-autistic adolescents, while autistic girls felt more socially alienated than all other groups considered in the study. After accounting for hyperactivity and emotional problems, all girls felt more socially alienated than boys. Only autistic boys were unhappier with friendships than non-autistic children. No group differences were found regarding romantic relationships. Some social experiences of adolescents vary greatly by both gender and diagnostic status. Further research should seek to examine the impact of these differences on mental health and well-being.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by deficits in social interactions, repetitive behaviors, and hyper- or hyposensitivity to sensory stimuli. The cellular mechanisms underlying the emergence of abnormal sensory sensitivity in ASD are not fully understood. Recent studies in rodent models of ASD identified differences in dorsal root ganglia (DRG) neurons that convey somatosensory information to the central nervous system. However, it is unknown how ASD-associated alterations in DRG neurons emerge during development and if these phenotypes are conserved across ASD models. We examined Pten (phosphatase and tensin homolog) heterozygous mice (Pten ^Het ) as a model for syndromic ASD and identified altered responses to sensory stimuli. Transcriptomic and in vivo analysis identified alterations in subtype-specific markers of DRG neurons in Pten ^Het mice, emerging during early DRG development and involving dysregulation of signaling pathways downstream of PTEN. Finally, we show that mice harboring an ASD-associated mutation (Pten ^Y69H ) show nearly identical alterations in the expression of somatosensory neuron subtype-specific markers. These results show that precise levels of PTEN are required for proper somatosensory development and provide insight into the molecular and cellular basis of sensory abnormalities in a model for syndromic ASD.

Respiratory sinus arrhythmia (RSA) is a key index of parasympathetic function and environmental adaptability. Lower resting RSA has been linked to preterm (PT) birth in infancy and autism spectrum disorder (ASD) in childhood, yet RSA across the first 2 years in young infants born PT or later diagnosed with ASD remains unknown. This study examined resting RSA and mean interbeat interval (IBI) development from 1 to 24 months in infants at varying ASD likelihoods, including infant siblings of children with ASD and those born PT. A longitudinal design tracked resting RSA and mean IBI in 137 infants from 1 to 24 months. Infants were classified as elevated likelihood for ASD (EL), low likelihood for ASD (LL), or PT and later classified by developmental outcome as ASD, neurodivergent (ND), or typically developing (TD). Mixed-effects models examined developmental trajectories and group differences. Results indicated that both RSA and mean IBI increased across all groups from 1 to 24 months, with the most rapid growth observed in the first 6 months. PT infants exhibited lower RSA and mean IBI initially, but aligned with LL infants when age was corrected for prematurity. Infants later diagnosed with ASD showed no early RSA differences, but exhibited elevated RSA from 9 to 24 months, distinguishing them from TD and ND infants. Elevated resting RSA in ASD from 9 to 24 months may reflect reduced social monitoring, increased attentional regulation, or decreased stress during a resting period free of structured tasks. These findings contrast with lower RSA in older children with ASD, highlighting developmental shifts in autonomic function and the need for further research into RSA as an early biomarker for ASD.