Characterizing Spontaneous Thought and Conscious Experience at Rest with EEG Microstate k-mers

Poster Session F - Tuesday, April 16, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Shirley Pandya¹ (sxp1464@miami.edu), Anthony P. Zanesco¹, Amishi P. Jha¹; ¹University of Miami

Characterizing the intrinsic dynamic activity of brain networks has proven to be an important goal of contemporary neuroscience research. One methodological approach involves probing the correspondence between spontaneous thought and ongoing brain dynamics while individuals are at rest. Large-scale electrophysiological events known as electroencephalographic (EEG) microstates provide an important window into whole-brain neuronal network activity at the millisecond time scale. The sequential nature of these microstates is thought to reflect aspects of phenomenologically tractable cognitive and perceptual states corresponding with individuals’ dynamic neurocognitive functioning. In the present EEG study, we examined the occurrence of microstate k-mers, substrings of microstate sequences of k length, to investigate their utility in predicting participants’ self-reported spontaneous thought during rest. Participants (N=64) were instructed to report on the content and quality of their spontaneous thought by answering questions adapted from the Amsterdam Resting-State Questionnaire (ARSQ) after 8 separate periods of 2-2.5 minutes of quiet eyes-closed rest. The frequency of k-mers were used as predictors of individuals’ ARSQ ratings using multivariate distance matrix regression, separately for each k length [2-10]. We found that microstate k-mers were significant predictors of spontaneous thought and felt experience for several k lengths. Recurrent loops of pairs of microstates were constitutive of the most prevalent k-mers across all lengths of k, suggesting a role for microstate bimers (k-mer length=2) in supporting ongoing phenomenology of conscious experience. These findings support the notion that EEG microstates reflect functionally relevant features of ongoing brain activity. Subsequences of microstates may encode individuals’ ongoing spontaneous thought.

Topic Area: METHODS: Electrophysiology