Frequency-specific cortical subnetworks support fast human swallowing.

Abstract

Fast, highly constrained sensorimotor acts require rapid coordination of distributed cortical systems on subsecond timescales. Here, we used source-resolved magnetoencephalography to characterise time-locked cortical connectivity during voluntary swallowing in 74 healthy adults. Cluster-based network statistics revealed focal swallowing-related connectivity changes confined to anatomically selective subnetworks. Undirected phase-lagged connectivity identified theta- and low-gamma weighted phase lag index (wPLI) effects involving somatosensory, motor, supramarginal, and insular regions. Directed connectivity revealed sparse high-gamma phase slope index (PSI) subnetworks centred on the primary somatosensory cortex and anterior insula. Time-window analyses demonstrated temporally evolving low-gamma interactions between posterior parietal and insular regions, while laterality analyses showed rightward theta-band directed asymmetries during later swallowing phases. In contrast, global graph-theoretical metrics and node-level hub measures remained largely stable after correction for multiple comparisons. These findings indicate that voluntary swallowing is supported by focal, frequency-specific, and temporally structured cortical interactions rather than broad global network reconfiguration.