Effect Of Transcutaneous Auricular Vagus Nerve Stimulation In Brain Functional And Heart Rate Variability On Healthy People

ObjectiveThis study focused on the effect of transcutaneous auricular vagus nerve stimulation(taVNS)in brain functional and vagal excitability on healthy people.And explore the regulatory mechanism on vagus excitability of the brain function after taVNS.MethodsHealthy people(n=29)were recruited and randomly divided into two groups.14 subjects received continuous taVNS for 8min,then sham taVNS(staVNS)after one week;and the sequence of stimulation in the other 15 subjects was opposite.Functional and structural imaging scanning were performed at resting state before stimulation,and the functional images were also scanned during stimulation.HRV was detected before and during stimulation.fALFF method was used to process fMRI data.DPABI 13.0 software was used for the resting state functional magnetic resonance images(fMRI)processing.SPSS 19.0 statistical software was used to process the basic information,fMRI and HRV data of these subjects according to different methods.Results1.fMRI results showed that,compared with the baseline state,fALFF values in the left lingual gyrus and left fusiform gyrus were significantly increased and fALFF values of left cerebellum during taVNS was significantly lower.Compared with baseline,fALFF values of left fusiform gyrus,left lingual gyrus,left cerebellum and left precuneus during staVNS were signi ficantly higher.Compared with staVNS,fALFF values in some areas of the left cerebellum during taVNS was significantly higher and left cerebellum,left fusiform gyrus and left lingual gyrus during taVNS were significantly lower.2.Results of HRV:Comparison of heart beat:baseline heart beat:353.00(322.00,378.00),taVNS heart beat:337.00(311.50,374.50),taVNS heart beat is significantly lower than baseline.Comparison of RR interval:baseline RR interval:844.00(793.00,897.50),taVNS RR interval:886.00(821.00,952.50),the value of taVNS RR interval is significantly higher than baseline.Comparison of r-MSSD:baseline r-MSSD:27.00(13.50,31.50),taVNS r-MSSD:28.00(18.00,37.00),staVNS r-MSSD:21.00(13.50,30.50),the value of taVNS r-MSSD is significantly higher than baseline(P<0.05),and compared with staVNS,the taVNS r-mssd value is also significantly higher.Comparison of PNN50:taVNS PNN50:28.70(7.00,46.85),staVNS PNN50:11.00(2.20,35.15).taVNS PNN50 is significantly higher than staVNS.Comparison of HF:taVNS HF:243.00(134.50,606.00),staVNS HF:143.00(99.00,478.00),HF value of taVNS is significantly higher than staVNS.4.Correlation analysis:the results showed that the change of fALFF signal in taVNS was significantly correlated with r-MSSD.ConclusiontaVNS can change the brain functions of the left cerebellum and left fusiform gyrus,suggesting that the cerebellum and fusiform gyrus may be potential targets of taVNS to regulate the emotional center.The change of fALFF value in the left cerebellum is related to the change of vagus nerve state with taVNS,indicating that taVNS can play a regulatory role on vagal excitability through the cerebellum.