深呼吸与迷走神经电刺激对大脑皮层静息态低频振幅分数影响的比较OA

Objective:To study the different effects of deep breathing and transcutaneous auricular vagus nerve stimulation(taVNS)on the fractional amplitude of low-frequency fluctuations(fALFF)in the resting-state cortex and their underlying mechanisms.Methods:In this randomized crossover design study,30 healthy volunteers com-pleted a single 20-minute session of deep breathing training and a single 20-minute session of taVNS,with the order of interventions randomized.The two sessions were separated by a washout period of at least 48 h.Measurements of 5-min heart rate variability(HRV)and resting-state functional near-infrared spectroscopy(fNIRS)were obtained immediately before and after each intervention.End-tidal carbon dioxide(PetCO2)was continuously monitored throughout the intervention process.Results:The deep breathing group exhibited significantly decreased PetCO2(P＜0.01),increased standard deviation of NN intervals(SDNN)(P＜0.05),and reduced fALFF in both prefron-tal cortex(PFC)and sensorimotor cortex(SMC)(P＜0.01).A significant positive correlation emerged between PetCO2 and fALFF at 15 min、20min(P＜0.01).Conversely,the taVNS group demonstrated increased root mean square of successive RR interval differences(RMSSD)(P＜0.01)and decreased low-frequency/high-frequency pow-er ratio(LF/HF)(P＜0.05),but no significant alterations in cerebral fALFF or PetCO2.Conclusion:The primary mechanism by which deep breathing induces a decrease in the fALFF in the cortex is mediated through CO2-induced vascular effects,whereas taVNS does not significantly modulate cortical fALFF.