Amplitude of low frequency fluctuations during resting state fMRI in autistic children.
Autistic kids show dampened resting brain activity in key social regions, but this flips to over-connection during tasks.
01Research in Context
What this study did
The team scanned 42 autistic kids and 38 typical kids during quiet rest.
They measured low-frequency brain waves called ALFF.
Higher ALFF means more brain chatter at rest.
What they found
Autistic kids had quieter parietal and insular regions.
These areas handle body awareness and social cues.
The gap grew with age, hinting at delayed maturation.
How this fits with other research
Zhao et al. (2024) adds motion to the picture.
They show autistic brains get stuck in one rigid state.
Together, the two papers paint a story of both weaker signals and less flexible networks.
Stevens et al. (2018) seems to disagree.
They found stronger long-range links during a motor task.
The clash vanishes when you note rest vs. task: quiet brains look weak, busy brains look over-connected.
Li et al. (2024) shows girls with autism drive most network changes.
This warns us not to treat all kids the same in future scans.
Why it matters
You can spot sensory and social struggles before they show in behavior.
Use this to time your interventions.
Pair quiet rest scans with active tasks to see the full brain story.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Add a 2-minute quiet period before sessions and note if the child seems to 'warm up' their brain — this may mirror the ALFF findings.
02At a glance
03Original abstract
Resting state fMRI (rs-fMRI) provides an excellent platform for examining the amplitude of low frequency fluctuations (ALFF) and fractional amplitude of low frequency fluctuations (fALFF), which are key indices of brain functioning. However, ALFF and fALFF have been used only sporadically to study autism. rs-fMRI data from 69 children (40 autistic, mean age = 8.47 ± 2.20 years; age range: 5.2 to 13.2; and 29 non-autistic, mean age = 9.02 ± 1.97 years; age range 5.9 to 12.9) were obtained from the Autism Brain Imaging Data Exchange (ABIDE II). ALFF and fALFF were measured using CONN connectivity toolbox and SPM12, at whole-brain & network-levels. A two-sampled t-test and a 2 Group (autistic, non-autistic) × 7 Networks ANOVA were conducted to test group differences in ALFF and fALFF. The whole-brain analysis identified significantly reduced ALFF values for autistic participants in left parietal opercular cortex, precuneus, and right insula. At the network level, there was a significant effect of diagnostic group and brain network on ALFF values, and only significant effect of network, not group, on fALFF values. Regression analyses indicated a significant effect of age on ALFF values of certain networks in autistic participants. Such intrinsically different network-level responses in autistic participants may have implications for task-level recruitment and synchronization of brain areas, which may in turn impact optimal cognitive functioning. Moreover, differences in low frequency fluctuations of key networks, such as the DMN and SN, may underlie alterations in brain responses in autism that are frequently reported in the literature.
Autism research : official journal of the International Society for Autism Research, 2023 · doi:10.1002/aur.2846