Neural Dynamics of Spontaneous Thought: An Electroencephalographic Study.

Spontaneous thinking is a ubiquitous aspect of our mental life and has increasingly become a hot topic of research in cognitive neuroscience. To date, functional neuroimaging studies of spontaneous thought have revealed general brain recruitment centered on a combination of default mode network and executive regions. Despite recent findings about general brain recruitment, very little is known about how these regions are recruited dynamically over time. The current research addresses this gap in the literature by using EEG to investigate the fine-grained temporal dynamics of brain activity underlying spontaneous thoughts. We employed the first-person reports of experienced meditators to index the onset of spontaneous thoughts, and examined brain electrical activity preceding indications of spontaneous thought onset. An independent component analysis-based source localization procedure recovered sources very similar to those previously found with fMRI (Ellamil et al. in Neurolmage 136:186-196, 2016). In addition, phase synchrony analyses revealed a temporal trajectory that begins with default network midline and salience network connectivity, followed by the incorporation of language and executive regions during the period from thought generation to appraisal.