Developmental Shift From Intrinsic Hyper- to Hypo-Connectivity Occurring at Pre-Adolescence in Autism Spectrum Disorder.

This study looked at brain connections in 800 people with autism across different ages. It found that young autistic children have too many brain connections, but this changes to too few connections around pre-teenage years. The brain networks that handle basic functions like hearing and movement change first, followed by networks involved in thinking and attention. This suggests autism affects the brain differently as children grow up.

This large-scale study analyzed brain connectivity patterns in 800 participants with autism spectrum disorder using data from the Autism Brain Imaging Data Exchange. Researchers identified six major brain networks and tracked how connectivity changes with age. The study found that autistic children initially show hyper-connectivity (excessive connections) between brain regions, which shifts to hypo-connectivity (reduced connections) during pre-adolescence. Primary sensory networks (auditory, motor, visual) undergo this transition earlier than higher-order cognitive networks (default mode, attention, salience networks).

This developmental pattern suggests that brain connectivity in autism follows a predictable age-related progression, with the critical transition occurring around pre-adolescence.

Findings suggest autism interventions should be tailored to developmental stage, with different approaches for hyper-connectivity in early childhood versus hypo-connectivity in adolescence. Sensory-based interventions may be particularly relevant in younger children, while cognitive and attention-based approaches may be more appropriate as connectivity patterns mature.

Study type not specified in abstract. Cross-sectional design limitations not discussed. Potential confounding factors like medication use, comorbidities, or developmental level not addressed. Generalizability across autism severity levels unclear.

Accumulating evidence suggests that hyper-connectivity is more characteristic of young children with autism spectrum disorder (ASD), while hypo-connectivity begins to emerge in adolescence and persists into adulthood. Despite increasing efforts being invested to explore the altered functional connectivity in ASD, the timing of the shift from intrinsic hyper-to hypo-connectivity of large-scale brain functional networks remains unclear. Here, we systematically depict the development of intrinsic functional connectivity in 800 participants from the Autism Brain Imaging Data Exchange. We first use independent component analyses to identify the large-scale brain functional networks.

Then, we utilize the locally estimated scatterplot smoothing algorithm to fit the developmental trajectory of brain functional networks. Finally, we develop a "sliding threshold" method to detect the age stage at which the shift from hyper- to hypo-connectivity occurs in ASD. We identify six large-scale brain functional networks, including the default mode network (DMN), fronto-parietal network (FPN), salience network (SAN), auditory network (AN), somatomotor network (SMN), and visual network (VN). We find that primary networks (AN, SMN, and VN) undergo the shift from hyper- to hypo-connectivity earlier than high-order networks (DMN, FPN, and SAN) in ASD.

At pre-adolescence, the SMN, AN, VN, DMN, SAN, and FPN undergo the shift from hyper- to hypo-connectivity in sequence in ASD. Our findings shed light on the age-related changes of intrinsic functional connectivity in ASD, highlighting the need for conceptualizing functional connectivity in ASD from a developmental perspective.