The subcortical correlates of autistic traits in school-age children: a population-based neuroimaging study.

This study looked at brain scans from over 7,000 children to see if autistic traits are linked to differences in deep brain structures. They found very little connection between autistic traits and the size of these brain areas. The research suggests that other parts of the brain might be more important for understanding autism-related differences.

This large-scale neuroimaging study examined brain structure differences in 7,005 typically developing children aged 9-10 years to understand if autistic traits correlate with subcortical brain anatomy. Using the Social Responsiveness Scale to measure autistic traits and MRI brain imaging, researchers found minimal evidence for meaningful associations between autistic traits and subcortical brain volumes. While small differences were initially observed in nucleus accumbens and putamen volumes, these disappeared when accounting for overall brain size. The study excluded children with moderate-severe autism diagnoses, limiting generalizability.

Findings suggest cortical brain measures may be more promising targets for identifying neurobiological markers of autistic traits than subcortical structures.

Results suggest that subcortical brain imaging may have limited utility as biomarkers for autism traits in clinical assessment. Research efforts may be better directed toward cortical brain measures or other neuroimaging approaches for understanding autism-related brain differences.

Study excluded children with moderate-severe autism diagnoses, potentially limiting generalizability. Social Responsiveness Scale scores may reflect general behavioral problems rather than autism-specific traits. Sample had lower average autistic traits than general population, potentially biasing results toward null findings.

There is emerging evidence that the neuroanatomy of autism forms a spectrum which extends into the general population. However, whilst several studies have identified cortical morphology correlates of autistic traits, it is not established whether morphological differences are present in the subcortical structures of the brain. Additionally, it is not clear to what extent previously reported structural associations may be confounded by co-occurring psychopathology. To address these questions, we utilised neuroimaging data from the Adolescent Brain Cognitive Development Study to assess whether a measure of autistic traits was associated with differences in child subcortical morphology, and if any observed differences persisted after adjustment for child internalising and externalising symptoms.

Our analyses included data from 7005 children aged 9-10 years (female: 47.19%) participating in the Adolescent Brain Cognitive Development Study. Autistic traits were assessed using scores from the Social Responsiveness Scale (SRS). Volumes of subcortical regions of interest were derived from structural magnetic resonance imaging data. Overall, we did not find strong evidence for an association of autistic traits with differences in subcortical morphology in this sample of school-aged children.

Whilst lower absolute volumes of the nucleus accumbens and putamen were associated with higher scores of autistic traits, these differences did not persist once a global measure of brain size was accounted for. It is important to note that autistic traits were assessed using the SRS, of which higher scores are associated with general behavioural problems, and therefore may not be wholly indicative of autism-specific symptoms. In addition, individuals with a moderate or severe autism diagnosis were excluded from the ABCD study, and thus, the average level of autistic traits will be lower than in the general population which may bias findings towards the null. These findings from our well-powered study suggest that other metrics of brain morphology, such as cortical morphology or shape-based phenotypes, may be stronger candidates to prioritise when attempting to identify robust neuromarkers of autistic traits.