EEG resting-state functional connectivity: evidence for an imbalance of external/ internal information integration in Autism

Abstract

Background Autism spectrum disorder (ASD) is associated with atypical neural activity in resting-state. Most of the studies have focused on abnormalities in alpha-frequency, as a marker of ASD dysfunctions. However, few have explored alpha synchronization, with a specific interest in resting-state networks: the default mode network (DMN), the sensorimotor network (SMN), and the dorsal attention network (DAN). These functional connectivity analyses provide relevant insight into the neurophysiological correlates of multimodal integration in ASD. Methods Using the high temporal resolution of EEG, the present study investigates the functional connectivity in the alpha band within and between the DMN, SMN, and the DAN. We examined eyes-closed EEG alpha lagged phase synchronization, using standardized Low-Resolution Brain Electromagnetic Tomography (sLORETA) in 29 participants with ASD and 38 age,- sex- and IQ-matched typically developing (TD) controls. Results We observed reduced functional connectivity in the ASD group relative to TD controls, within and between the DMN, the SMN, and the DAN. We identified three hubs of dysconnectivity in ASD: the posterior cingulate cortex, the precuneus, and the medial frontal gyrus. These three regions also presented decreased current source density in the alpha band. Conclusion These results may account for impairments in multimodal - sensory and internal information - integration frequently observed in ASD. Underconnectivity potentially involves difficulties switching between this externally oriented attention and internally oriented thoughts and, more broadly, may impact embodied cognition.

Macro- and Microstates of Resting-State EEG in Children with Low-Functioning Autism

“…According to previous ndings the reported microstate could be associated with visual or verbal processing (Britz et al, 2010); (Milz et al, 2016) as well as scene-reconstruction activity (Brechet et al, 2019) and had a higher presence in individuals with ASD (Jia & Yu, 2019). Moreover, according to recent studies, individuals with ASD had di culties in switching between externally oriented attention and internally oriented thoughts and respectively could be more engaged with visual scene-reconstruction memories and sensory processing during the resting state (Wantzen et al, 2022). Taking into account the results of correlation analysis when the higher prefrontal 2-6 Hz oscillatory activity correlated with the shorter coverage of Cluster #5 and the previous ndings on the association of visual imagery with an increase in delta-rhythm power in frontal areas (Koizumi et al, 2018); (Sousa et al, 2017), we may conclude that the speci c macrostate/Cluster #5 re ects more engagement of visual imagery and sensory processing in children with ASD during resting-state conditions.…”