Decoding cross-modality sensorimotor synchronization: Unveiling a general network using functional and efficiency...

Auditory is the dominant modality for sensorimotor synchronization, but this dominance disappears with visual continuous stimuli. Whether the intrinsic processing of sensorimotor synchronization (SMS) is modality-specific or cross-modal remains unclear. A synchronization-continuation tapping task was conducted with varying modalities (visual/auditory) and temporal structures (discrete/continuous) while recording fNIRS signals over a set of lateral cortical regions. We constructed fNIRS-based functional connectivity networks from HbO time series (pairwise Pearson correlations among channels, sparsity-thresholded), and quantified graph metrics including small-worldness and betweenness centrality. Across conditions, the networks showed small-world organization, and FP, dlPFC, and pre-SMA exhibited relatively higher betweenness centrality within the sampled cortical network, consistent with hub-like roles. Exploratory Granger causality analyses further suggested a directional connectivity pattern from sensory regions to IPL and to these hub-like nodes, with reciprocal interactions among the hub-like nodes. Overall, our findings characterize a hub-like cortical subnetwork within the regions sampled by fNIRS that may support cross-condition coordination during SMS.