Disrupted multi-frequency topological properties of brain functional networks in attention networks after repetitive subconcussion.

Attention impairment constitutes a primary cognitive deficit following subconcussive head impacts. However, the underlying neural mechanisms remain unclear. This study investigated neural alterations in attention networks associated with repetitive subconcussive exposure by integrating source-level electroencephalography (EEG) functional connectivity analysis with the Attention Network Test (ANT). Source-level functional connectivity matrices were constructed using the phase-locking value (PLV) to characterize connectivity patterns across multiple frequency bands (delta, theta, alpha, and beta), and graph-theoretical analysis was subsequently performed to assess network topological properties. At the behavioral level, attention network efficiency did not differ significantly between groups; however, compared with healthy controls, the subconcussion group exhibited increased functional connectivity across attention networks. Specifically: (1) Within the alerting network, connectivity increased in the delta and alpha bands; exploratory correlations analyses indicated that stronger connectivity between the rolandic operculum (ROL) and the inferior parietal lobule, as well as between the ROL and the angular gyrus, was associated with better alerting efficiency, whereas stronger connectivity between the middle frontal gyrus and the supplementary motor area (SMA) was associated with poorer alerting efficiency. (2) Within the orienting network, widespread increases in connectivity were observed across the delta, alpha, and beta bands, and stronger connectivity between the supramarginal gyrus and the middle temporal pole was associated with better orienting efficiency. (3) Within the executive control network, right-hemisphere-predominant enhancement of connectivity in the alpha and beta bands was accompanied by significant alterations in network topological organization. Collectively, these findings reveal frequency-specific functional hyperconnectivity and selective topological reorganization within attention networks following repetitive subconcussion, providing insights into subconcussion-related neural alterations and potential neurophysiological signatures for further investigation.