Functional changes during visuo-spatial working memory in autism spectrum disorder: 2-year longitudinal functional magnetic resonance imaging study.
Autistic brains do not increase power when visual memory load rises, so watch for hidden overload even when kids seem to keep up.
01Research in Context
What this study did
Dudley et al. (2019) tracked the same kids for two years. They scanned both autistic and neurotypical children while the kids did a visual memory game that got harder each round.
The team wanted to see if brain activation changed with age and with the tougher levels.
What they found
Typical kids used more brain power when the game got harder. Autistic kids kept the same brain response even when the load increased.
Their neural engine did not rev up with demand, a sign of immature modulation.
How this fits with other research
Schlink et al. (2022) looked at the same kind of memory and saw no behavior gap—autistic kids improved with age just like peers. The new fMRI result seems to clash, but it measures brain fuel use, not test scores. Behavior can look fine while the brain works overtime.
Cummings et al. (2024) pooled many studies and also found autistic executive skills grow at the same rate. Again, the brain picture and the behavior picture differ. Neural efficiency lags even when outward progress looks normal.
Leung et al. (2014) showed autistic kids ignore helpful big-picture cues in visual tasks. The flat brain response in M et al. may be the neural reason: the system does not ramp up when extra structure is added.
Why it matters
You may see a teen with ASD finish memory tasks yet melt down when homework piles on. The scan study tells us the brain is not gearing up for heavier load, even if the child appears to cope. Offer external scaffolds—shorter lists, visual timers, frequent breaks—before demand snowballs.
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02At a glance
03Original abstract
This study examined functional changes longitudinally over 2 years in neural correlates associated with working memory in youth with and without autism spectrum disorder, and the impact of increasing cognitive load. We used functional magnetic resonance imaging and a visuo-spatial 1-back task with four levels of difficulty. A total of 14 children with autism spectrum disorder and 15 typically developing children (ages 7-13) were included at baseline and followed up approximately 2 years later. Despite similar task performance between groups, differences were evident in the developmental trajectories of neural responses. Typically developing children showed greater load-dependent activation which intensified over time in the frontal, parietal and occipital lobes and the right fusiform gyrus, compared to those with autism spectrum disorder. Children with autism spectrum disorder showed minimal age-related changes in load-dependent activation, but greater longitudinal load-dependent deactivation in default mode network compared to typically developing children. Results suggest inadequate modulation of neural activity with increasing cognitive demands in children with autism spectrum disorder, which does not mature into adolescence, unlike their typically developing peers. Diminished ability for children with autism spectrum disorder to modulate neural activity during this period of maturation suggests that they may be more vulnerable to the increasing complexity of social and academic demands as they progress through adolescence than their peers.
Autism : the international journal of research and practice, 2019 · doi:10.1177/1362361318766572