Task modulation of intrinsic low-frequency temporal connectivity in the brain default mode network

Recent neuroimaging studies have led to the proposal that a specific set of regions, referred to as the default mode network (DMN), is engaged when individuals are at rest. Temporal activity within the network is characterized by spontaneous intrinsic low-frequency fluctuations. However, it is still unclear how the low-frequency temporal connectivity within DMN regions changes under different types of external task modulation. In particular, while previous studies have examined the behavior of the DMN at rest or under continuous, attention-demanding tasks that deactivate the DMN [1,2], it is not known how DMN connectivity is modulated by tasks that activate major nodes of the DMN. In the current study, we use both cluster analysis and marginal/partial correlation analysis to quantify and compare how low-frequency temporal connectivity of the DMN changes during sustained tasks that activate and deactivate major regions of the DMN.