Abstract
BackgroundFunctional neuroimaging research in autism spectrum disorder has reported patterns of decreased long-range, within-network, and interhemispheric connectivity. Research has also reported increased corticostriatal connectivity and between-network connectivity for default and attentional networks. Past studies have excluded individuals with autism and low verbal and cognitive performance (LVCP), so connectivity in individuals more significantly affected with autism has not yet been studied. This represents a critical gap in our understanding of brain function across the autism spectrum.MethodsUsing behavioral support procedures adapted from Nordahl, et al. (J Neurodev Disord 8:20–20, 2016), we completed non-sedated structural and functional MRI scans of 56 children ages 7–17, including LVCP children (n = 17, mean IQ = 54), children with autism and higher performance (HVCP, n = 20, mean IQ = 106), and neurotypical children (NT, n = 19, mean IQ = 111). Preparation included detailed intake questionnaires, video modeling, behavioral and anxiety reduction techniques, active noise-canceling headphones, and in-scan presentation of the Inscapes movie paradigm from Vanderwal et al. (Neuroimage 122:222–32, 2015). A high temporal resolution multiband echoplanar fMRI protocol analyzed motion-free time series data, extracted from concatenated volumes to mitigate the influence of motion artifact. All participants had > 200 volumes of motion-free fMRI scanning. Analyses were corrected for multiple comparisons.ResultsLVCP showed decreased within-network connectivity in default, salience, auditory, and frontoparietal networks (LVCP < HVCP) and decreased interhemispheric connectivity (LVCP < HVCP=NT). Between-network connectivity was higher for LVCP than NT between default and dorsal attention and frontoparietal networks. Lower IQ was associated with decreased connectivity within the default network and increased connectivity between default and dorsal attention networks.ConclusionsThis study demonstrates that with moderate levels of support, including readily available techniques, information about brain similarities and differences in LVCP individuals can be further studied. This initial study suggested decreased network segmentation and integration in LVCP individuals. Further imaging studies of LVCP individuals with larger samples will add to understanding of origins and effects of autism on brain function and behavior.
Highlights
Functional neuroimaging research in autism spectrum disorder has reported patterns of decreased long-range, within-network, and interhemispheric connectivity
We present an approach for evaluating brain function and connectivity in an low verbal and cognitive performance (LVCP) sample of young participants
When GSR is applied, which effectively normalizes the median connection to be zero, the effect of generalized decreased connectivity is removed, and the same pattern is seen for LVCP vs. higher verbal and cognitive performance and autism (HVCP) as for LVCP vs. neurotypical individuals
Summary
Functional neuroimaging research in autism spectrum disorder has reported patterns of decreased long-range, within-network, and interhemispheric connectivity. New behavioral support methodology from Nordahl, et al [6] achieved success in structural imaging of 9– 13-year-old LVCP individuals without sedation They utilized a Board Certified Behavior Analyst to facilitate individualized behavioral techniques, repeated mock scanner sessions, motion sensors for positive differential reinforcement during scanning, and repeated scans to obtain acceptable levels of head movement. They were able to achieve excellent results in 18 individuals with an average IQ level of 65 (range 41–108), including 10 children with very low language performance (standard scores ≤ 40 on the Verbal Ability index of the Differential Ability Scales, Second Edition, range 26.7–40). Cox et al [7] focused on reducing head motion in children with autism in-scan procedure tasks over multiple trials (range 3–67), but concluded that behavioral techniques may be best suited to individuals with autism and higher language and cognitive performance
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