When Self Comes to a Wandering Mind: data and code This repository contains the predictive models, data, and codes to generate the main figures for the following publication: "When Self Comes to a Wandering Mind: Brain Representations and Dynamics of Self-generated Concepts in Spontaneous Thought", Byeol Kim Lux, Jessica R Andrews-Hanna, Jihoon Han, Eunjin Lee, Choong-Wan Woo, Science Advances, 2022 Dependencies:https://github.com/canlab/CanlabCore https://github.com/cocoanlab/cocoanCORE*Note that the current study used these repositories (which are also based on the SPM toolbox) for all fMRI data analyses. Abstract 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.