Abstract
Cognition is dynamic and involves both the maintenance of and transitions between neurocognitive states. While recent research has identified some of the neural systems involved in sustaining task states, it is less well understood how intrinsic influences on cognition emerge over time. The current study uses fMRI and Multi-Dimensional Experience Sampling (MDES) to chart how cognition changes over time from moments in time when external attention was established. We found that the passage of time was associated with brain regions associated with external attention decreasing in activity over time. Comparing this pattern of activity to defined functional hierarchies of brain organization, we found that it could be best understood as movement away from systems involved in task performance. Moments where the participants described their thoughts as off-task showed a significant similarity to the task-negative end of the same hierarchy. Finally, the greater the similarity of a participant’s neural dynamics to this hierarchy the faster their rate of increasing off-task thought over time. These findings suggest topographical changes in neural processing that emerge over time and those seen during off-task thought can both be understood as a common shift away from neural motifs seen during complex task performance.
Highlights
Cognition is dynamic and involves both the maintenance of and transitions between neurocognitive states
If neural hierarchies constrain the temporal dynamics linked to off-task thinking (a) neural changes associated with the passage of time should match the topographical motifs seen in one or more neurocognitive hierarchies, (b) the same topographical neural motifs will be seen during patterns of off-task thought, and (c) the extent of these temporal changes should be related to individual variation in patterns of ongoing thought
We used these moments as a reference point from which temporal changes can be calculated, generating a regressor describing for each non-target the amount of time passed since the last behavioural response. Using this as an explanatory variable in a whole-brain analysis we found no regions that increased over time, multiple regions showed the reverse pattern
Summary
Cognition is dynamic and involves both the maintenance of and transitions between neurocognitive states. Contemporary cognitive neuroscience has established that neural functioning is organised along multiple hierarchies that together are assumed to give rise to the structure of human cognition[10] These hierarchies reflect different aspects of cognition including distinctions between unimodal and transmodal systems[11], dissociations between sensory systems[12], and neurocognitive patterns linked to complex task performance[2,13]. We selected three well-established neuro-cognitive hierarchies reflecting (i) the distinction between unimodal and transmodal systems, (ii) visual and sensorimotor systems, and (iii) the patterns describing the brains response to cognitive tasks, identified in a previous study[11] Using these spatial maps as descriptions of the constraints neural hierarchies place on function, we tested whether they provide a framework to understand the dynamic changes that characterise transitions between states of external task focus and off-task self-generated experiences. If neural hierarchies constrain the temporal dynamics linked to off-task thinking (a) neural changes associated with the passage of time should match the topographical motifs seen in one or more neurocognitive hierarchies, (b) the same topographical neural motifs will be seen during patterns of off-task thought, and (c) the extent of these temporal changes should be related to individual variation in patterns of ongoing thought
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
