Sleep Electroencephalography Power Spectral Response to Transcutaneous Auricular Vagus Nerve Stimulation on Insomnia Rats

Background: Insomnia is a prevalent sleep disorder and strong risk factor for poor quality of life, depression, and other lifestylerelated diseases. Objectives: To investigate the effect of the transcutaneous vagus nerve stimulation (taVNS) on sleep electroencephalographic (EEG) in the para-chlorophenylalanine (PCPA) insomnia rats. Methods: Rats were divided into control, model, taVNS and sham taVNS (stnVNS) (stimulate the auricular margin, as transcutaneous none VNS, stnVNS) group (n=6 in each group). A week before the experiment, the electrodes were fixed to the skull of all the rats for recording the sleep EEG. PCPA was used to establish insomnia models. The rats of taVNS and stnVNS group were treated via an electroacupuncture apparatus for seven consecutive days, and simultaneously, the sleep EEG were recorded for all groups after the treatment daily. And the power spectrum analysis was used in this experiment. Results: After modeling, the percentage of power spectrum of delta frequency band significantly decreased, while the theta, alpha, and beta frequency bands significantly increased in the model group compared to the control group. After intervention, the percentage of the delta frequency band significantly increased in the taVNS group as compared to the stnVNS group. Conclusion: These results suggest that taVNS can significantly modulate the power spectrum of the delta frequency band and may constitute a potential low-cost alternative for the treatment of insomnia.