Electroencephalographic cross-frequency coupling and multiplex brain network under manual acupuncture stimulation

Abstract

Abstract Increasing evidence indicates that acupuncture can modulate neural system dynamic and brain activity. Except for within-frequency coupling (WFC), cross-frequency coupling (CFC) also plays a crucial role in the process of information transfer and integration within brain areas. In this paper, with the cross-frequency phase synchronization technique, CFC under acupuncture is investigated using multi-channel EEG signals during acupuncture at “Zusanli” acupoint. The results show that the CFC under acupuncture significantly increases in delta-theta, delta-alpha, and theta-alpha bands. Brain functional networks including WFC networks and multiplex CFC networks are further reconstructed. The evolution of WFC network structure under acupuncture is explored by graph metrics, and it is found that the value of small world index significantly declines in delta and theta bands while increases in alpha and beta bands in acupuncture state. The ability of functional integration and segregation of the cross-frequency networks are further quantified via multiplex network features. In CFC network, the increments of multiplex clustering coefficient (MCC) and multiplex participation coefficient (MPC) in alpha and beta bands indicate that acupuncture could promote information integration and segregation across high rhythms. In addition, post-effect of acupuncture is obvious in alpha and beta bands, which can infer that alpha and beta rhythms play an essential part in the modulation of brain function by acupuncture. Besides, the change of matrix eigenvalue indicates that acupuncture impacts on brain dynamics by changing brain structure. These results provide a novel perspective to explore the alteration of brain function under manual acupuncture stimulation.