Dynamics of neural recruitment surrounding the spontaneous arising of thoughts in experienced mindfulness practitioners

By studying experienced mindfulness practitioners who can closely observe when a thought first arises, researchers identified distinct brain regions that activate before versus after a thought emerges. Activity in the medial temporal lobe and inferior parietal lobule peaked before the thought began, suggesting these areas help generate spontaneous thoughts. In contrast, regions including the medial prefrontal, temporopolar, mid-insular, lateral prefrontal, and dorsal anterior cingulate cortices activated at or just after the thought's onset, indicating a role in elaborating or reflecting on the thought. These timing differences may explain why spontaneous thoughts are so varied and how they connect to memory and attention.

Study at a glance

Abstract

Thoughts arise spontaneously in our minds with remarkable frequency, but tracking the brain systems associated with the early inception of a thought has proved challenging. Here we addressed this issue by taking advantage of the heightened introspective ability of experienced mindfulness practitioners to observe the onset of their spontaneously arising thoughts. We found subtle differences in timing among the many regions typically recruited by spontaneous thought. In some of these regions, fMRI signal peaked prior to the spontaneous arising of a thought - most notably in the medial temporal lobe and inferior parietal lobule. In contrast, activation in the medial prefrontal, temporopolar, mid-insular, lateral prefrontal, and dorsal anterior cingulate cortices peaked together with or immediately following the arising of spontaneous thought. We propose that brain regions that show antecedent recruitment may be preferentially involved in the initial inception of spontaneous thoughts, while those that show later recruitment may be preferentially involved in the subsequent elaboration and metacognitive processing of spontaneous thoughts. Our findings highlight the temporal dynamics of neural recruitment surrounding the emergence of spontaneous thoughts and may help account for some of spontaneous thought's peculiar qualities, including its wild diversity of content and its links to memory and attention.