Divergent task-dependent functional connectivity of executive control and salience networks

Background: Previous studies have demonstrated task-dependent functional interactions of a frontal-parietal control system with the competing dorsal attention (DA) and default mode networks (DM). However, evidence suggests that the frontal-parietal control system is functionally heterogeneous, consisting of two distinct sub-networks that demonstrate dissociable intrinsic functional connectivity (FC) patterns: a frontal-parietal "executive control network" (CON) and a cingulo-opercular "salience network" (SAL). In this study, we aimed to test the hypothesis that CON and SAL would show dissociable task-dependent changes in connectivity with regard to the competing DA and DM when switching from rest to external task performance.

Methods: Nineteen healthy adults underwent four functional MRI scans: two during rest and two while performing a global-local selective attention task. Seed-based FC defined the CON and SAL. Connectivity changes between task and rest states were assessed by analysis of variance. The relationship of task-dependent changes in connectivity for each of these networks with behavioral measures was also characterized.

Results: CON and SAL demonstrated distinct stable and task-dependent regional connectivity. Whereas CON primarily increased FC with visual cortex regions associated with the DA during task performance versus rest, the SAL increased coupling with regions belonging to the DM. Greater dissociation between CON and SAL and between regions with which they coupled during task was associated with better task accuracy.

Conclusions: The divergent task-dependent dynamics of CON and SAL connectivity with the anti-correlated DA and DM support distinct functional roles of these two "control" networks.