Research On EEG Induced By Acupuncture At Zusanli Point

Acupuncture is an important part of Chinese medicine with unique ways of thinking and rich experiences whose efficacy has been proved by Chinese clinical research during thousands of years, but the exact mechanism of acupuncture is still unclear. Many scientists have worked on the physiological basis of Chinese medicine and attempt to explain the acupuncture points and meridians using modern scientific technology. An experiment is designed that acupuncture at Zusanli point of right leg is taken with four different frequencies to obtain electroencephalograph (EEG) signals in this paper, and nonlinear EEG analysis methods are applied to explore and study the effects of acupuncture on brain activity.Firstly, we use correlation dimension and determinism index methods based on order recurrence plot to extract the complexity parameter of EEG. The effects of acupuncture on the functional regions of brain and correlations between different acupuncture frequencies and the complexity of EEG are investigated. The results show that the complexity of EEG during acupuncture is higher than that before acupuncture, especially during acupuncture with frequency of 100 times/min. This provides some theoretical supports to acupuncture on patient with appropriate frequency.Secondly, five kind of EEG rhythms () are extracted by the wavelet transform, and effects of acupuncture on five kinds of rhythms and order of brain activities are investigated by the wavelet packet energy entropy and determinism index based on order recurrence plot. It is found that the acupuncture affect on these rhythms to different extent. Furthermore, we find correlations between acupuncture frequency and the complexity of different EEG rhythms.Last but not the least, in order to investigate the information communication between different brain areas during acupuncture, a mutual information method based on order recurrence plot is applied to extract the characteristic parameters of EEG under different conditions. The results show that the synchronization of the left and right brain areas were enhanced when acupuncture is applied. But the synchronization between left and right brain changed little. The obtained results prove that acupuncture causes obvious effect on brain activity, and can provide some theoretical supports to the acupuncture therapy on cognitive impairment and other related diseases...