Multi-modal imaging reveals complex brain alterations associated with autism spectrum disorder

Autism spectrum disorder (ASD) is a growing global concern, affecting approximately 2.8% of children in the United States and 0.7% in China. ASD is characterized by challenges in social interaction, communication difficulties, and repetitive behaviors, making early diagnosis critical for improving outcomes. However, current diagnostic methods rely primarily on behavioral observations, which may delay early interventions. Despite ongoing research, the structural and functional brain differences between children with ASD and typically developing (TD) children remain poorly understood.

Now, in a recent study published in NeuroImage and made available online on February 28, 2025, researchers from Japan have investigated the link between white matter fiber tracts and brain functional connectivity in young children with ASD. The study was led by Professor Akemi Tomoda from the University of Fukui, Japan, with co-authors Jia Wang and Lijie Wu from the Public Health College of Harbin Medical University, along with Natasha Y.S. Kawata and Takashi X. Fujisawa from the University of Fukui.

The study examined 34 children with ASD and 43 TD children using magnetic resonance imaging (MRI) to analyze white matter tracts-bundles of nerve fibers that link different brain areas-and measure functional connectivity between these regions. The team employed a novel approach called the population-based bundle-to-region connectome to gain a more detailed understanding of the connections.

The findings revealed significant differences in brain connectivity between the two groups, particularly in the left hemisphere. Children with ASD exhibited altered connectivity patterns and differences in the density and organization of neural pathways. These findings suggest impaired integrity and potential developmental delays in the formation of critical brain networks. Notably, the researchers identified specific white matter tracts linked to core ASD symptoms, providing new insights into how these structural differences relate to behavior.

Most importantly, this approach found that these connectivity differences were associated with specific ASD symptoms. “We observed that superior longitudinal fasciculus was associated with repetitive behaviors, whereas cingulum connectivity correlated more with communication abilities,” explains Prof. Tomoda, “These findings highlight the potential of multi-modal imaging in identifying ASD-related brain changes, helping to refine diagnostic criteria and guide the development of targeted interventions.”

Identifying these structural and functional connectivity patterns could pave the way for more objective diagnostic tools. As Prof. Tomoda explains, “For instance, MRI-based biomarkers, such as changes in fractional anisotropy or mean diffusivity in the superior longitudinal fasciculus or cingulum, could help in earlier and more precise ASD diagnosis.”

Moreover, the implications of this study are not limited to early diagnosis and also extend towards new treatments. “Our results could inform the design of personalized interventions,” adds Prof. Tomoda. “Therapeutic approaches, such as neurofeedback or brain stimulation techniques, could be tailored to improve connectivity in specific white matter tracts, potentially addressing repetitive behaviors or enhancing communication abilities in children with ASD as needed.“

Overall, this study underscores the importance of multi-modal imaging approaches like MRI in capturing the complex brain alterations associated with ASD. Future work in this field could open new pathways for improving diagnostic accuracy, tailoring interventions, and ultimately enhancing the quality of life for individuals with ASD and their families.