The landscape of ongoing thought is heterogeneous and shaped by both personal traits and environmental context. Recent work shows that attention and control systems organize experience in response to changing demands, while the default mode network contributes not only to task-negative or episodic content but also to the vividness of experience in both task contexts and spontaneous self-generated states. Multiple neural systems reflect the landscape of ongoing thought, and it is important to distinguish processes that shape how experience unfolds from those that regulate it.
People whose brain connectivity patterns make the sensorimotor system most distinct from the visual system are more likely to report thoughts about solving problems or goals and less likely to report thoughts about the past. This finding comes from a study where participants underwent resting-state fMRI and then completed a questionnaire about their thoughts during the scan. A non-linear dimension reduction algorithm identified components explaining the greatest variance in whole-brain connectivity patterns. The results suggest that unique patterns of experience are linked to distinct neurocognitive profiles, with unimodal systems playing an important role.
The brain's default mode network (DMN) contains spatially distinct subregions that support different cognitive processes: some DMN areas are more active during perceptual decisions about faces, while others are more active during memory-guided decisions based on previously seen images. These subregions differ in their connectivity profiles—perception-related areas have receiver-like, afferent-biased connections across the heteromodal cortex, whereas memory-related areas have sender-like, efferent-biased connections with perceptual-motor and attentional systems beyond the DMN. This double dissociation, found across three fMRI datasets, suggests that DMN architecture is organized to flexibly support both external perception and internal memory-guided thought.