Microstate analysis in infancy: Examining infant brain at rest and during experimental tasks.

Microstates are brief, stable states of spatial topography that are measured with electroencephalography (EEG) and thought to capture whole-brain activation patterns. EEG microstates have been associated with functional networks measured with functional magnetic resonance imaging (fMRI) in adult populations. Microstate analysis offers a unique opportunity to measure brain activity, capturing whole-brain dynamics with superior temporal sensitivity as infants engage in cognitive and emotionally salient tasks. Additionally, comparison of microstates between infants and the adult literature provide insight into functional network emergence and development. The current study examined microstates in 61 infants (ages 6-12 months) utilized a wakeful resting task in addition to laboratory tasks designed to elicit cognitive and emotional responses. The EEG microstate topographies and parameters were compared within these tasks and across activities. It was hypothesized that microstates would be extracted from infant EEG data, with resting (or baseline) topographies providing replication of previous work (Brown & Gartstein, 2023). It was hypothesized that the experimental tasks would produce four microstates similar in topography to the resting task, eliciting a calm/alert state, and that parameters would differ within and across tasks depending on the underlying functional networks needed to process information specific to each activity. Similar topographies were found across tasks and were consistent with the adult literature. Topographies and parameters differed in comparisons within and across tasks consistent with the associated functional networks. These findings point to the usefulness of microstate analysis in measuring emotional processing and cognition and how these emerge as a function of brain development.