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Updated: May 23, 2025
Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging
Published on: September 12, 2011
White matter microstructure as a potential contributor to differences in resting state alpha activity between
Guannan Shen1,2, Heather L Green3, Marybeth McNamee3
1Lurie Family Foundations MEG Imaging Center, Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA. sheng1@chop.edu.
Insights
Resting-state peak alpha frequency (PAF) is higher in children with autism spectrum disorder (ASD) and linked to optic radiation white matter maturation in both ASD and typically developing children. This suggests PAF as a potential brain marker for ASD.
Area of Science:
- Neuroscience
- Developmental Psychology
- Biomarkers for Autism Spectrum Disorder (ASD)
Background:
- Resting-state peak alpha frequency (PAF) is a potential clinical marker for young children with autism spectrum disorder (ASD).
- Previous studies show higher PAF in school-age children with ASD versus typically developing (TD) children.
- Associations between resting-state PAF and processing speed differ between TD and ASD groups.
Purpose of the Study:
- To investigate the brain mechanisms underlying differences in resting-state PAF between children with ASD and TD children.
- To examine the longitudinal maturation of resting-state PAF and optic radiation white matter in children.
- To assess the association between resting-state PAF, optic radiation white matter, and processing speed.
Main Methods:
- Longitudinal study of 59 TD and 56 ASD children aged 6-8 years at baseline.
- Measures included resting-state peak alpha frequency (PAF) via magnetoencephalography (MEG) and optic radiation white matter via diffusion tensor imaging (DTI).
- Brain measures were collected at baseline and approximately 1.5 and 3 years later.
Main Results:
- Parietal-occipital PAF increased with age in both groups; ASD children consistently showed higher PAF than TD children.
- Resting-state PAF predicted processing speed in TD children but not in children with ASD.
- More mature optic radiation white matter was associated with a higher PAF in both ASD and TD groups.
Conclusions:
- Findings support the use of resting-state PAF as a brain marker in children with ASD aged 6-10 years.
- The study replicates the association between resting-state PAF and processing speed in TD but not ASD children.
- Group differences in resting-state PAF were not explained by differences in optic radiation white matter maturation.
Abstract:
We and others have demonstrated the resting-state (RS) peak alpha frequency (PAF) as a potential clinical marker for young children with autism spectrum disorder (ASD), with previous studies observing a higher PAF in school-age children with ASD versus typically developing (TD) children, as well as an association between the RS PAF and measures of processing speed in TD but not ASD. The brain mechanisms associated with these findings are unknown. A few studies have found that in children more mature optic radiation white matter is associated with a higher PAF. Other studies have reported white matter and neural activity associations in TD but not ASD. The present study hypothesized that group differences in the RS PAF are due, in part, to group differences in optic radiation white matter and PAF associations. The maturation of the RS PAF (measured using magnetoencephalography(MEG)), optic radiation white matter (measured using diffusion tensor imaging(DTI)), and associations with processing speed were assessed in a longitudinal cohort of TD and ASD children. Time 1 MEG and DTI measures were obtained at 6-8 years old (59TD and 56ASD) with follow-up brain measures collected ~ 1.5 and ~ 3 years later. The parietal-occipital PAF increased with age in both groups by 0.13 Hz/year, with a main effect of group showing the expected higher PAF in ASD than TD (an average of 0.26 Hz across the 3 time points). Across age, the RS PAF predicted processing speed in TD but not ASD. Finally, more mature optic radiation white matter measures (FA, RD, MD, AD) were associated with a higher PAF in both groups. Present findings provide additional evidence supporting the use of the RS PAF as a brain marker in children with ASD 6-10 years old, and replicate findings of an association between the RS PAF and processing speed in TD but not ASD. The hypothesis that the RS PAF group differences (with ASD leading TD by about 2 years) would be explained by group differences in optic radiation white matter was not supported, with brain structure-function associations indicating that more mature optic radiation white matter is associated with a higher RS PAF in both groups.
