Background Unusual behavioral reactions to sensory stimuli are frequently reported in individuals on the autism spectrum (AS). Despite the early emergence of sensory features (< age 3) and their potential impact on development and quality of life, little is known about the neural mechanisms underlying sensory reactivity in early childhood autism. Methods Here, we used electroencephalography (EEG) to investigate tactile cortical processing in young children aged 3–6 years with autism and in neurotypical (NT) children. Scalp EEG was recorded from 33 children with autism, including those with low cognitive and/or verbal abilities, and 45 age- and sex-matched NT children during passive tactile fingertip stimulation. We compared properties of early and later somatosensory-evoked potentials (SEPs) and their adaptation with repetitive stimulation between autistic and NT children and assessed whether these neural measures are linked to “real-world” parent-reported tactile reactivity. Results As expected, we found elevated tactile reactivity in children on the autism spectrum. Our findings indicated no differences in amplitude or latency of early and mid-latency somatosensory-evoked potentials (P50, N80, P100), nor adaptation between autistic and NT children. However, latency of later processing of tactile information (N140) was shorter in young children with autism compared to NT children, suggesting faster processing speed in young autistic children. Further, correlational analyses and exploratory analyses using tactile reactivity as a grouping variable found that enhanced early neural responses were associated with greater tactile reactivity in autism. Limitations The relatively small sample size and the inclusion of a broad range of autistic children (e.g., with low cognitive and/or verbal abilities) may have limited our power to detect subtle group differences and associations. Hence, replications are needed to verify these results. Conclusions Our findings suggest that electrophysiological somatosensory cortex processing measures may be indices of “real-world” tactile reactivity in early childhood autism. Together, these findings advance our understanding of the neurophysiological mechanisms underlying tactile reactivity in early childhood autism and, in the clinical context, may have therapeutic implications.

Approximately 10% of births are preterm (PTB; <37 weeks gestational age; GA), which confers risk for cognitive, behavioral, and mental health challenges. Using the large and relatively diverse (i.e., designed to reflect sociodemographic variation in the US population) Adolescent Brain Cognitive DevelopmentSMStudy (ABCD Study®), we characterized the impact of PTB on brain structure in middle-late childhood (9-10 years). The ABCD sample covers the GA spectrum, and the large sample size (∼11,500) permits consideration of how associations between PTB and brain structure are impacted by GA, sex, birthweight, and analytic choices such as controlling for total brain size. We found a pattern of relative cortical thinning in temporoparietal and dorsal prefrontal regions and thickening of medial prefrontal and occipital regions in PTB compared to children born full term (≥37 weeks GA). This pattern was apparent when controlling for mean thickness and when considering moderate (>32 and <37 weeks GA) and very PTB (≤32 weeks GA) separately, relative to full term birth. Surface area and subcortical volumes showed reductions in PTB children that were largely attenuated when controlling for brain size. Effects on cortical thickness and surface area were partially mediated by birthweight. Although boys are at increased risk for adverse outcomes following PTB, there was limited evidence of sex differences of PTB effects. Finally, cortical thickness effects estimated in a ‘discovery’ sample (N=7528) predicted GA in a holdout ‘replication’ sample (N=2139). Our findings help to clarify the effects of PTB on brain structure into late childhood across the GA spectrum.SignificancePreterm birth (PTB) affects ∼10% of children and increases the risk of neurodevelopmental and mental health challenges. Here we examined long-term effects of PTB on brain structure in middle-late childhood in the large and relatively diverse ABCD sample. We further assessed the influence of gestational age, sex, birthweight, controlling for brain size and data quality. Our findings replicate a pattern of occipitotemporal and dorsal prefrontal cortical thinning in PTB that was seen in both moderate preterm and very preterm relative to full-term birth. Effects were similar in males and females and partially mediated by birthweight. Our findings suggest that community-recruited children born preterm show a pattern of structural alterations on a continuum that relates to gestational age and birthweight.