EEG theta-band phase synchronization during electrical acupuncture in humans

The main purpose of the present paper was: (1) to study the phase synchronization pattern in the θ g-band while performing the classical acupuncture on Neiguan(PC6) and Shenmen (HT7); (2) to study hemispheric differences in the degree of synchronization during acupuncture. Multivariate electroencephalograph signals from 15 subjects were recorded while performing acupuncture and also at resting condition. Phase synchronization was measured by a recent index, mean phase coherence. It was found that phase synchrony was strongly increased between parietal (P5, PO5) and frontal (FP3, Fz, FC6) areas and occipital areas (POZ) during and after acupuncture with respect to rest. Phase synchrony was decreased between frontal and frontal (FP3, Fz, FC6) areas. The synchronization between the occipital areas and the frontal areas during the needle retaining section was more synchronized than the sections before. The occipital areas was more synchronized than the frontal (FP3, Fz, FC6) areas after electro acupuncture.