Tutorial on using EEG microstates to study moment-to-moment large-scale functional brain network dynamics in neurodevelopment.

EEG microstates are topographical patterns of EEG activity that offer a lens into the fast temporal dynamics of large-scale functional network activity and whole-brain functional organization. Microstates can capture temporal patterns of network configurations and transitions between these configurations at the millisecond scale. Although extensively studied in adults, microstates remain underutilized in developmental neuroscience, despite their potential for tracking significant developmental changes in brain network dynamics indicated by developmental fMRI studies. Extracting EEG microstates from developmental populations with relatively high artifact levels compared to adults remains a challenge due to the sensitivity of the method to such artifacts. Our tutorial provides a practical guide that walks the readers through the microstate analysis pipeline with a focus on special considerations for developmental data within the free, open-source software HAPPE (Harvard Automated Processing Pipeline for Electroencephalography) that is optimized for developmental artifacts. We first detail the conceptual foundations and current status of EEG microstates in developmental literature and then present a step-by-step tutorial on computing and interpreting microstates from resting-state and task-based EEG in developmental cohorts. All de-identified datasets used in the tutorial and the annotated microstate analysis code are freely available for public access at https://zenodo.org/records/17527065 and https://github.com/PINE-Lab/HAPPE/blob/master/3.%20generate/generateMicroStates.m. This article aims to make microstate computation more accessible, robust, and reproducible in developmental cognitive neuroscience.