Research On EEG-EMG Signal Coherence And Information Entropy Under Different Modes

Body movement is generated between the nervous system and muscle tissue under the condition of information exchange, and is controlled by the cerebral cortex. Cortex issued instructions, through the central nervous system, which along the motion pathway to control body to complete muscle movement. At the same time, limb somatosensory feedback along the sensory pathway to the spinal cord, brainstem and cerebellum. The somatosensory feedback is analyzed comprehensively in sensory and motor areas of the brain, and adjust the movement instruction to complete accurately action. The interaction between the brain and muscle contraction, indicating that there is coherence properties of certain between EEG and EMG signals. The acupoints around have intensive sensory nerve endings and blood vessels. The question is whether motor neurons and the specific areas of cerebral cortex are activated under the stimulation of acupuncture points, which is the focus of the research and application.(1) Transcutaneous Electrical Acupoint Stimulation(TEAS) paradigm is designed and a platform for experiments is built. Under continuous wave intermittent wave and dilatational wave electrical stimulation of different frequency, stimulating the Neiguan and Quchi two acupoints, the signals of FC3, C3, CP3, FC4, C4, CP4 total six brain conductance and flexor carpi are acquired and recorded synchronously under the voluntary contraction mode and the acupoint electric stimulation mode.(2) By using adaptive notch filter and wavelet threshold denoising, the power frequency interference、 artifact and noise are removed. Induced EEG and sEMG signals purely are obtained.(3) By using the methods of time domain, frequency domain and time-frequency, the feature of Surface Electromyography (SEMG) is analyzed under acupoint electric stimulation. By comparison with the sEMG signals of voluntary contraction movement, the results indicating:under acupoint electric stimulation, the root mean square(RMS) of sEMG increases amplitude and the power spectrum of sEMG moves to higher frequency; Mean Power Frequency(MPF) and Median Frequency(MF) of sEMG are stable and rising; The energy of sEMG is high and equal division. Indicating that the excitement of motor neurons is caused under Transcutaneous Electrical Acupoint Stimulation(TEAS).(4) By using the method of nonlinear on wavelet entropy、sample entropy, the characteristics of EEG and EMG signals are studied, and the complexity and orderliness of EEG and EMG signals is explored. Under acupoint electric stimulation, the wavelet entropy、sample entropy of EEG and EMG signals are changed. Indicating that the brain central nervous and the motor neurons are activated, which reduce the complexity of the sequence and enhance the orderliness of sequence. So the coordination of EEG-EMG is improved.(5) By using the method of Wavelet coherence factor, the coherence properties of EEG-EMG signals are studied. The results indicating:Under acupoint electric stimulation, the coherence properties of EEG-EMG signals are mainly concentrated in the 15-30Hz band, which correspond to the beta (15-30Hz) rhythm of the brain. Under the voluntary contraction, the coherence properties of EEG-EMG signals are mainly concentrated in the 30-40Hz band, which correspond to the gamma (30-40Hz) rhythm of the brain. Under the dilatational wave acupoint electrical stimulation, the coherence properties of EEG-EMG signals are most pronounced. Acupoint electric stimulation induced contraction of the arm muscle and contralateral motor areas of the brain have the strongest coherence.Results of this study can be applied to artificial intelligence、bionic robot、 rehabilitation and sports medicine, and brain cognitive science research. The results lay the foundation for the thorough understanding of the relationship between the muscles and the brain activities, and have both science and application value.