Extraction And Analysis Of Eeg Features Under Magnetic Stimulation At Acupuncture Point

Magnetic stimulation is a technique of painless and non-invasive. It is effective to modulate nerve activities, treat disorders and maintain health, just like acupuncture. Magnetic stimulation at acupuncture point (acupoint) is an example of modern medical technique combination with traditional Chinese medicine. It will improve both of them.In this thesis, magnetic stimulation was used to stimulate acupuncture point (acupoint) of Neiguan, Hegu and Zusanli in human body. EEG signals were recorded before, during and after magnetic stimulation. The features of EEG signals were extracted and analyzed to determine the effects of magnetic stimulation parameters on the brain evoked potentials, the different effects of magnetic stimulation at acupoint and mock point, and the corresponding relationships between acupoint and automatic functional areas of brain. The main points of this thesis are:1,Effects of magnetic stimulation frequency on the brain evoked potentialsNeiguan acupoint was stimulated by pulsed magnetic field with different frequencies. The evoked potentials were analyzed. The results showed that the evoked potential components of P150 and P300 were induced by low-frequency magnetic stimulation at Neiguan acupoint, and no evoked potentials were induced by high-frequency stimulation. The results provided evidence for the optimal stimulation frequency.2,Effects of magnetic stimulation intensity on the brain evoked potentialsNeiguan acupoint was stimulated by pulsed magnetic field with different intensities. The evoked potentials were analyzed. The results showed that the latency of evoked potentials was shorter and the amplitude was bigger under high-intensity stimulation. The results provided evidence for the optimal stimulation intensity.3,Comparison of the brain evoked potentials induced by magnetic stimulation at Neiguan acupoint and mock pointThe evoked potentials induced by magnetic stimulation at Neiguan aupoint and mock point were analyzed. The results showed that evoked potential components of P150 and P300 were induced by magnetic stimulation at Neiguan acupoint and only P150 was induced by magnetic stimulation at mock point. It suggested that magnetic stimulation at Neiguan acupoint would induce more complicated brain activities.4,Cerebral source locations of the brain evoked potentialsThe cerebral source locations of the evoked potential components were discussed. P150 located in the contralateral anterior cingulated cortex (ACC), as a stress reaction of brain to the external stimulation. P300 located in hippocampi. It might be related to Neiguan acupoint effects. The results indicated the probable mechanisms underlying central nervous system of the effect difference between magnetic stimulation at Neiguan acupoint and mock point.5,Analysis of complexity of EEG signals under magnetic stimulation at Neiguan acupoint and the mock pointC0 complexity of EEG signals was calculated before and after magnetic stimulation at Neiguan acupoint and mock point. The statistical analysis results showed that the values of C0 complexity of EEG signals were much bigger after magnetic stimulation at Neiguan acupoint than those before stimulation in bilateral frontal lobe, contralateral temporal lobe and homonymous occipital lobe. That is, the activities of these areas were activated. And activities of mass areas of celebral cortex were deactivated after magnetic stimulation at mock point. It suggested that the short-term post effects were different between magnetic stimulation at Neiguan acupoint and mock point.6,Corresponding relationships between acupoint and automatic functional areas of brainThe values of C0 complexity of EEG signals before and after magnetic stimulation at Neiguan, Hegu and Zusanli acupoint and brain information mappings of different states showed that the activities of bilateral frontal lobe, contralateral temporal lobe and homonymous occipital lobe were activated after magnetic stimulation at Neiguan acupoint, celebral parietal lobe activities were deactivated after magnetic stimulation at Hegu acupoint, and the activities of homonymious occipital lobe were activated after magnetic stimulation at Zusanli acupoint. The results suggested that the relationships between acupoints and automatic functional areas of brain were specific respectively. It provided evidence for the theory of acupoint specificity.