Mind-wandering, a common daily mental activity, varies uniquely from person to person. In three individuals who each reported hundreds of mind-wandering episodes during multiple fMRI sessions, reliable links between mind-wandering and default mode network (DMN) activation emerged when brain networks were analyzed within each person. However, the timing of spontaneous DMN activity relative to subjective reports, and the broader networks activated or deactivated during mind-wandering, differed across individuals. Whole-brain connectivity patterns that predicted mind-wandering within an individual did not fully generalize to others, and predictive models from larger datasets largely failed when applied to these densely-sampled individuals. This work demonstrates both conserved and variable neural representations of mind-wandering, highlighting the value of personalized approaches.
A new method called real-time fMRI-triggered experience-sampling (rt-fMRI-ES) was developed to capture spontaneous thoughts with better temporal precision. During a resting state, brain activity in the dorsal anterior insular cortex (part of the salience network) and posteromedial cortex (part of the default mode network) was monitored in real time to trigger thought probes. In 42 to 49 participants, the method did not support the hypothesis that arousal ratings would be higher when triggered by insular activation, but it did support the hypothesis that external-attention ratings were lower when triggered by posteromedial cortex activation. The rt-fMRI-ES technique successfully enables efficient sampling of spontaneous thoughts based on ongoing neural activity.
A new method called real-time fMRI-triggered experience sampling (rt-fMRI-ES) was developed to capture spontaneous thoughts with better temporal precision. In 42 to 49 participants at rest, brain activity in the posteromedial cortex (a default mode network region) was used to trigger thought probes. When probes were triggered by activity in this region, participants reported lower external attention compared to other trials, supporting the hypothesis that default mode network activity relates to internally focused thought. However, the hypothesis that dorsal anterior insular cortex activity would correspond to higher arousal ratings was not supported. The method offers a way to study spontaneous thought based on ongoing neural activity.