Frequency-specific dynamic characteristics of brain networks during salt taste perception: an EEG-based functional...

Salt taste is one of the five basic taste modalities, yet its central processing mechanisms at the level of functional connectivity and directional information flow remain poorly understood. In this study, scalp EEG electrodes were functionally parcellated into four functional subnetworks: the Gustatory Perception Subnetwork, Emotional Association Subnetwork, Cognitive Evaluation Subnetwork, and Multisensory Integration Subnetwork. EEG data were collected from 20 healthy participants under a water baseline and five NaCl concentrations. Phase locking value (PLV), graph-theoretical analysis, and partial directed coherence (PDC) were employed to examine salt-induced phase synchronization, network integration, and directional information flow, respectively, across δ to γ bands. Results showed that salt stimulation significantly enhanced whole-brain and inter-subnetwork phase synchronization (p < 0.05, FDR-corrected), with the strongest PLV response at low concentration (mean PLV = 0.550), indicating that weak salt input can trigger robust cross-network integration. Topological analysis revealed low-concentration-dominant nonlinear network reorganization rather than a linear concentration-dependent increase. PDC analysis showed that low-intensity salty stimulation enhanced effective connectivity in the β band from the gustatory perception subnetwork to the multisensory integration subnetwork. Directional asymmetry analysis further revealed a relatively consistent outward information-flow bias of the Gustatory Perception Subnetwork, together with condition- and frequency-dependent directional interactions among the other subnetworks. These findings characterize the frequency-specific EEG network dynamics of salt taste perception in terms of phase synchronization, topological reorganization, and directional information interactions, and provide new evidence for the central processing of salt taste signals.

The online version contains supplementary material available at https://doi.org/10.1007/s11571-026-10558-5.