Abstract
One of the central topics in cognitive neuroscience revolves around understanding how responses in the default mode network (DMN) relate to cognitive process and disease states. While there has been many investigations of the intrinsic patterns of activation and connectivity of the DMN with other networks at rest, i.e. when an individual is not engaged in any particular behavior, to truly understand the influence and significance of the DMN activation and connectivity, we must study it in association with a particular process. Reward processing is an integral part of goal-directed behavior that has been shown to rely on the striatum, a subcortical brain region that is connected to multiple regions of the prefrontal cortex (PFC) that belong to the DMN. Yet, it remains unclear how the DMN interacts with the striatum during reward processing. To investigate this issue, we analyzed card-guessing task data of 453 subjects from the Human Connectome Project and applied a novel network-based psychophysiological interaction analysis (nPPI) that quantified reward-dependent connectivity of the DMN. We show that only the DMN exhibits increased connectivity with the ventral striatum (VS) during the receipt of reward. This result was specific to the DMN and the strength of connectivity was associated with the personality characteristic of openness. These findings point to a novel role of the DMN during reward processing, and to the nPPI approach being able to capture a unique contribution of a collection of regions to task performance.
Significance The default mode network (DMN) has been theorized to participate in a range of social, cognitive, and affective functions. Yet, previous accounts do not consider how the DMN contributes to other brain regions depending on psychological context, thus rendering our understanding of DMN function incomplete. We addressed this gap by applying a novel network-based psychophysiological interaction analysis to the reward task within the Human Connectome Project. We found that the experience of reward enhances task-dependent connectivity between the DMN and the ventral striatum. Surprisingly, the strength of connectivity was correlated with personality characteristics relating to openness. These results advance models of DMN by demonstrating how it contributes to other brain systems and how those contributions relate to individual differences.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Conflict of interest statement The authors have no conflicts to disclose.
Data and code availability Statistical maps can be found on NeuroVault. Analysis code can be found on https://github.com/DVS-Lab/dmn-reward.