クロスモーダル感覚運動同期の解読：機能的ネットワークと効率的ネットワークによる一般ネットワークの解明

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.