Default mode network connectivity during task execution

The default mode network, long thought to be deactivated during focused tasks and to interfere with performance, may actually help fulfill cognitive demands. In a finger-tapping task with functional MRI, the network showed task-specific changes in its topography. Faster reaction times were predicted by stronger connectivity between the posterior cingulate cortex and the left superior frontal gyrus. The network's connections reconfigured dynamically during the task, maintaining efficient small-world organization while supporting higher-level parallel processing. These results suggest the default mode network does not disengage but may contribute to task-relevant processing.

Study at a glance

Abstract

Initially described as task-induced deactivations during goal-directed paradigms of high attentional load, the unresolved functionality of default mode regions has long been assumed to interfere with task performance. However, recent evidence suggests a potential default mode network involvement in fulfilling cognitive demands. We tested this hypothesis in a finger opposition paradigm with task and fixation periods which we compared with an independent resting state scan using functional magnetic resonance imaging and a comprehensive analysis pipeline including activation, functional connectivity, behavioural and graph theoretical assessments. The results indicate task specific changes in the default mode network topography. Behaviourally, we show that increased connectivity of the posterior cingulate cortex with the left superior frontal gyrus predicts faster reaction times. Moreover, interactive and dynamic reconfiguration of the default mode network regions' functional connections illustrates their involvement with the task at hand with higher-level global parallel processing power, yet preserved small-world architecture in comparison with rest. These findings demonstrate that the default mode network does not disengage during this paradigm, but instead may be involved in task relevant processing.