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.
Portraying the unique contribution of the default mode network to internally driven mnemonic processes
