When self comes to a wandering mind: Brain representations and dynamics of self-generated concepts in spontaneous thought

Self-relevant concepts are major building blocks of spontaneous thought, and their dynamics in a natural stream of thought are likely to reveal one's internal states important for mental health. Here we conducted an fMRI experiment (n = 62) to examine brain representations and dynamics of self-generated concepts in the context of spontaneous thought using a newly developed free association-based thought sampling task. The dynamics of conceptual associations were predictive of individual differences in general negative affectivity, replicating across multiple datasets (n = 196). Reflecting on self-generated concepts strongly engaged brain regions linked to autobiographical memory, conceptual processes, emotion, and autonomic regulation, including the medial prefrontal and medial temporal subcortical structures. Multivariate pattern-based predictive modeling revealed that the neural representations of valence became more person-specific as the level of perceived self-relevance increased. Overall, this study provides a hint of how self-generated concepts in spontaneous thought construct inner affective states and idiosyncrasies.

Relationship between Spatiotemporal Dynamics of the Brain at Rest and Self-Reported Spontaneous Thoughts: An EEG Microstate Approach

Rationale: The resting-state paradigm is frequently applied in electroencephalography (EEG) research; however, it is associated with the inability to control participants’ thoughts. To quantify subjects’ subjective experiences at rest, the Amsterdam Resting-State Questionnaire (ARSQ) was introduced covering ten dimensions of mind wandering. We aimed to estimate associations between subjective experiences and resting-state microstates of EEG. Methods: 5 min resting-state EEG data of 197 subjects was used to evaluate temporal properties of seven microstate classes. Bayesian correlation approach was implemented to assess associations between ARSQ domains assessed after resting and parameters of microstates. Results: Several associations between Comfort, Self and Somatic Awareness domains and temporal properties of neuroelectric microstates were revealed. The positive correlation between Comfort and duration of microstates E showed the strongest evidence (BF10 > 10); remaining correlations showed substantial evidence (10 > BF10 > 3). Conclusion: Our study indicates the relevance of assessments of spontaneous thought occurring during the resting-state for the understanding of the intrinsic brain activity reflected in microstates.

Predicting mind wandering episodes quarter hours in advances from EEG

Mind wandering occurs when spontaneous thought generation is increased while cognitive control is decreased, presumably in response to antagonistic effects of default mode- (DMN) and goal-directed network (GDN) activity. Previous studies assumed that DMN or GDN activity manifests in behavior with minimal delays and has rigid effects, i.e., DMN always facilitates generation of spontaneous thought and inhibits cognitive control. With those static response functions, the antagonism of DMN and GDN could explain the alternation of task focused and mind wandering states. But it rules out others, such as multi-tasking, where spontaneous thought and cognitive control are both increased, or rumination, where both are decreased. However, shifts from task focused to mind wandering have been shown to occur via a multi-tasking state. We therefore propose dynamic response functions, allowing delay or reversal of DMN and GDN effects. Dynamic response functions enabled us to stochastically predict mind wandering up to at least 30 min in advance from EEG measures of DMN and GDN activity in a tone counting task. Experimental results show both considerable delays and switches between task-positive and negative effects. Mind wandering was initiated by a barrage of DMN activity more than 20 minutes prior a report of mind wandering, directing the mental focus inward. Critically, facilitation of spontaneous thoughts occurred several minutes prior to the report. These thoughts sustained up to 10 min, after which a rebound to task-focused behavior was effectuated, notably without intervention from the GDN. Repeated GDN interventions, however, secured a basic level of task performance.

Narrative thinking lingers in spontaneous thought

What we think about at any moment is shaped by what preceded it. Why do some experiences, such as reading an immersive story, feel as if they linger in mind beyond their conclusion? In this study, we hypothesize that the stream of our thinking is especially affected by "deeper" forms of processing, emphasizing the meaning and implications of a stimulus rather than its immediate physical properties or low-level semantics (e.g., reading a story vs. reading disconnected words). To test this idea, we presented participants with short stories that preserved different levels of coherence (word-level, sentence-level, or intact narrative), and we measured participants’ self-reports of lingering and spontaneous word generation. Participants reported that stories lingered in their minds after reading, but this effect was greatly reduced when the same words were read with sentence or word-order randomly shuffled. Furthermore, the words that participants spontaneously generated after reading shared semantic meaning with the story’s central themes, particularly when the story was coherent (i.e., intact). Crucially, regardless of the objective coherence of what each participant read, lingering was strongest amongst participants who reported being ‘transported’ into the world of the story while reading. We further generalized this result to a non-narrative stimulus, finding that participants reported lingering after reading a list of words, especially when they had sought an underlying narrative or theme across words. We conclude that recent experiences are most likely to exert a lasting mental context when we seek to extract and represent their deep situation-level meaning.

Spontaneous thought and microstate activity modulation by social imitation

Social imitation increases well-being and closeness by mechanisms that remain poorly understood. We propose that imitation impacts behavioural states in part by modulating post-imitation mind-wandering. The human mind wanders spontaneously and frequently, revisiting the past and imagining the future of self and of others. External and internal factors can influence wandering spontaneous thoughts, whose content predicts subsequent emotional states. In 43 young subjects, we find that imitating the arm movements of an actor alters the dynamics and the content of subsequent resting-state spontaneous thoughts. Imitation-sensitive features of spontaneous thoughts correlate with both behavioural states and salivary oxytocin levels. EEG microstate analysis reveals that global patterns of correlated neuronal activity predict imitation-induced changes in spontaneous thoughts. Thus, imitation can modulate ongoing activity in specific neural networks to change spontaneous thought patterns as a function of oxytocin levels, and to ultimately orchestrate behavioural states.