The regulations on topological organization of prefrontal-sensorimotor cortical network elicited by tonifying and reducing manipulations of acupuncture: A graph theory analysis study based on fNIRS

This study aims to investigate the similarities and differences in the topological organization of prefrontal-sensorimotor cortical network (PFC-SMC) induced by traditional tonifying and reducing manipulations of acupuncture (TRMs), including the tonifying, reducing, and even tonifying-reducing manipulations. Thirty-five healthy participants underwent all three types of TRMs while functional near-infrared spectroscopy data were recorded. To characterize the network properties, graph-theoretical analysis was applied to calculate topological metrics at both global and nodal levels. Based on these metrics, k-means++ clustering analysis was subsequently performed to assess the representational and discriminative capacity of the derived features across different acupuncture manipulation. The results revealed that all three acupuncture manipulations perserved the typical small-world properties of the PFC-SMC network (p < 0.05, false discovery rate [FDR] corrected). However, further comparison showed that both the even tonifying-reducing manipulation and the reducing manipulation elicited significantly higher clustering coefficient and network efficiency than the tonifying manipulation (p_FDR < 0.05). At the nodal level, the tonifying manipulation showed lower nodal betweenness centrality and nodal degree centrality than the other two acupuncture manipulations (p_FDR < 0.05). Notably, these topological properties enabled reliable differentiation among the three TRMs, as confirmed by the clustering analysis. These findings highlight that different acupuncture manipulations exert distinct modulatory effects on the brain functional network, providing visualized evidence for facilitating the understanding and clinical application of TRMs.