Dynamic brain network interactions underlying human thought and spontaneous cognition

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Spontaneous thought, including spontaneously arising memories, images, and narratives, is central to human experience. Most studies to date have employed a cognitive task to examine off-task thought, or have used the resting-state in the fMRI scanner. Neither of these paradigms, however, capture the dynamics of thought that I have recently argued are essential for understanding spontaneous mental processes (Christoff et al., 2016, NRN). The proposed research builds on this theoretical framework to explore the characteristics of dynamically arising thoughts. The specific objectives will be to:1. Expand our knowledge about how different brain networks dynamically interact to contribute to different forms of dynamic dimensions of thought2. Develop novel paradigms for first-person reporting of subjective experience that capture ongoing thought flowThe first two projects will capitalize on the introspective expertise of contemplative practitioners. Project 1 aims to uncover the neural correlates of a newly identified dimension of thought how freely thought moves through a mindset manipulation. Expert contemplative practitioners will alternate between focused attention vs. open monitoring meditation during an fMRI scan. Open monitoring (vs. focused attention) is expected promote freely moving thought and be marked by stronger functional connectivity (FC) in the medial temporal lobe part of the default network (DN) because it is supplying the spontaneous mental content. Project 2 will examine the neural basis of automatic constraints on thought by asking contemplative practitioners to rate the level of difficulty in disengaging from their spontaneously arising thoughts. Dynamic FC measures will be used to assess the temporal patterns of key brain networks in leading up to a spontaneously arising thought. Recent behavioral evidence from our lab suggests freely moving thought is lowest in the morning and highest after noon. Project 3 will examine freely moving thoughts at different times during the day in the fMRI scanner (8AM vs. 1PM) in order to understand the neural basis underlying these differences across the diurnal cycle. We hypothesize that we will see differences in FC within the salience network across different times in the day. Finally, Project 4 will develop a new methodology that can capture the dynamic changes in thought over time. We will extend the standard experience sampling paradigm towards a continuous sampling method in which participants report their thoughts as they unfold.The proposed work will go beyond conventional methods for investigating spontaneous thought in order to expand our understanding of dynamic brain networks interactions that shape mental experience. This research will have important implications for education and workplace practices where considerations have focused on off-task thought to the exclusion of dynamic dimensions of thought.