Exploring Dynamic Thought Patterns using fMRI and Experience Sampling

One of the most striking features of human consciousness is its ability to foster an ongoing, seemingly continuous stream of thought. Prior studies have provided valuable insights into the neural correlates of the content of thought (e.g., whether it is task related or not). However, independent of its content, the stream of thought can also be characterized by its dynamics—how it changes over time. The Dynamic Framework of Thought proposes a neural model of how different large-scale brain networks may contribute to thoughts that are freely moving (spontaneous) or deliberately constrained. We empirically tested this model using a neurophenomenological approach, in which participants reported the nature of their thought stream in real time during fMRI scanning. Consistent with the model predictions, freely-moving thought was associated with greater activation of the default network (especially the medial-temporal subcomponent) than the frontoparietal control network, whereas deliberately constrained thought was associated with the opposite pattern of activation. Additionally, these distinct thought dynamics were reflected in the changes in the functional coupling patterns within and between these networks. These findings suggest that experience sampling, in conjunction with fMRI, can illuminate the neural basis of subtle thought dynamics.