Transcranial direct current stimulation reshapes the high-speed dynamic Organization of the autistic brain: An EEG microstate and brain network analysis.

Abstract

BackgroundAutism Spectrum Disorder (ASD) is characterized by atypical brain network organization and reduced neural flexibility. While transcranial direct current stimulation (tDCS) shows promise in alleviating symptoms, the underlying neurophysiological mechanisms and objective biomarkers remain poorly understood.ObjectiveThis study aimed to investigate how targeted tDCS modulates the high-speed dynamic organization of the autistic brain using EEG microstate and complex network analysis.MethodsIn this randomized controlled trial, 52 children with ASD were assigned to either an experimental group (n = 26) receiving a 5-week course of tDCS targeting the left dorsolateral prefrontal cortex (DLPFC) or a control group (n = 26). Clinical symptoms were assessed using the ABC and SRS scales. Resting-state EEG data were analyzed using microstate segmentation, wPLI-based functional connectivity, spatiotemporal variability, and first-order autoregressive modeling of state transitions.ResultsPost-intervention, the experimental group showed a significant increase in the occurrence and coverage of microstate A and microstate B, alongside a decrease in microstate C and D duration. Graph theoretical analysis revealed enhanced global and local efficiency, particularly in microstate B networks. Furthermore, tDCS significantly increased temporal variability while reducing spatial noise across microstate windows. Notably, the increase in microstate A occurrence was exclusively and negatively correlated with reductions in ABC and SRS scores, while no such correlations were found for other metrics.ConclusionTargeted tDCS reduces neural rigidity in children with ASD by enhancing spatiotemporal flexibility and optimizing information processing efficiency. Microstate A dynamics may serve as a robust electrophysiological biomarker for monitoring intervention efficacy in pediatric ASD populations.