Abstract:
Sinusoidal galvanic vestibular stimulation (sGVS) induces robust modulation of muscle sympathetic nerve activity (MSNA) alongside perceptions of side-to-side movement, sometimes with an accompanying feeling of nausea. We recently showed that transcranial alternating current stimulation (tACS) of the dorsolateral prefrontal cortex (dlPFC) also modulates MSNA, but does not generate any perceptions. Here, we tested the hypothesis that when the two stimuli are given concurrently, the modulation of MSNA would be additive. MSNA was recorded from 11 awake participants via a tungsten microelectrode inserted percutaneously into the right common peroneal nerve at the fibular head. Sinusoidal stimuli (± 2 mA, 0.08 Hz, 100 cycles) were applied in randomised order as follows: (i) tACS of the dlPFC at electroencephalogram (EEG) site F4 and referenced to the nasion; (ii) bilateral sGVS applied to the vestibular apparatuses via the mastoid processes; and (iii) tACS and sGVS together. Previously obtained data from 12 participants supplemented the data for stimulation protocols (i) and (ii). Cross-correlation analysis revealed that each stimulation protocol caused significant modulation of MSNA (modulation index (paired data): 35.2 ± 19.4% for sGVS; 27.8 ± 15.2% for tACS), but there were no additive effects when tACS and sGVS were delivered concurrently (32.1 ± 18.5%). This implies that the vestibulosympathetic reflexes are attenuated with concurrent dlPFC stimulation. These results suggest that the dlPFC is capable of blocking the processing of vestibular inputs through the brainstem and, hence, the generation of vestibulosympathetic reflexes.
摘要:
正弦电前庭刺激(sGVS)诱导肌肉交感神经活动(MSNA)的强大调节,以及对左右运动的感知,有时伴随着恶心的感觉。我们最近表明,背外侧前额叶皮层(dlPFC)的经颅交流电流刺激(tACS)也可以调节MSNA,但不会产生任何感知。这里,我们检验了当两个刺激同时给予时的假设,MSNA的调制将是相加的。通过经皮插入腓骨头右侧腓总神经的钨微电极,记录了11名清醒参与者的MSNA。正弦刺激(±2mA,0.08Hz,按以下随机顺序应用100个周期):(i)在脑电图(EEG)部位F4处的dlPFC的tACS,并参考nasion;(ii)通过乳突过程将双侧sGVS应用于前庭设备;(iii)tACS和sGVS一起。先前从12名参与者获得的数据补充了刺激方案(i)和(ii)的数据。互相关分析显示,每种刺激方案都引起MSNA的显着调制(调制指数(配对数据):sGVS为35.2±19.4%;tACS为27.8±15.2%),但是当tACS和sGVS同时递送时没有累加效应(32.1±18.5%)。这意味着同时dlPFC刺激会减弱前庭交感神经反射。这些结果表明,dlPFC能够通过脑干阻断前庭输入的处理,因此,前庭交感神经反射的产生。