Department of Psychology, Rutgers University, 101 Warren St, Newark, NJ 07102, USA.
Department of Psychology, Rutgers University, 101 Warren St, Newark, NJ 07102, USA.
Brain Stimul. 2017 Jan-Feb;10(1):19-27. doi: 10.1016/j.brs.2016.10.008. Epub 2016 Oct 20.
Stimulation of the vagus nerve via implanted electrodes is currently used to treat refractory epilepsy and depression. Recently, a non-invasive approach to vagal stimulation has demonstrated similar beneficial effects, but it remains unclear whether these effects are mediated via activation of afferent vagal fibers.
The present study was designed to ascertain whether afferent vagal projections can be accessed non-invasively by transcutaneous electrical stimulation of the antero-lateral surface of the neck, which overlies the course of the vagus nerve.
Thirteen healthy subjects underwent 2 fMRI scans in one session. Transcutaneous electrical stimulation was applied for 2 min to the right postero-lateral surface of the neck during scan #1 (control condition, sternocleidomastoid stimulation: "SCM") and to the right antero-lateral surface of the neck during scan #2 (experimental condition, non-invasive vagus nerve stimulation: "nVNS"). Two analyses were conducted using FSL (whole-brain and brainstem; corrected, p < 0.01) to determine whether nVNS activated vagal projections in the brainstem and forebrain, compared to baseline and SCM stimulation.
Compared to baseline and control (SCM) stimulation, nVNS significantly activated primary vagal projections including: nucleus of the solitary tract (primary central relay of vagal afferents), parabrachial area, primary sensory cortex, and insula. Regions of the basal ganglia and frontal cortex were also significantly activated. Deactivations were found in the hippocampus, visual cortex, and spinal trigeminal nucleus.
The present findings provide evidence in humans that cervical vagal afferents can be accessed non-invasively via transcutaneous electrical stimulation of the antero-lateral surface of the neck, which overlies the course of the nerve, suggesting an alternative and feasible method of stimulating vagal afferents.
目前，通过植入电极刺激迷走神经被用于治疗难治性癫痫和抑郁症。最近，一种非侵入性的迷走神经刺激方法已经证明了类似的有益效果，但尚不清楚这些效果是否是通过激活传入迷走神经纤维介导的。
本研究旨在确定通过经皮刺激颈部前外侧表面是否可以非侵入性地触及传入迷走神经投射，该表面覆盖了迷走神经的走行。
13 名健康受试者在一次会话中进行了 2 次 fMRI 扫描。在扫描 #1（对照条件，胸锁乳突肌刺激：“SCM”）期间，向右侧颈后侧表面施加 2 分钟的经皮电刺激，在扫描 #2（实验条件，非侵入性迷走神经刺激：“nVNS”）期间，向右侧颈前外侧表面施加 2 分钟的经皮电刺激。使用 FSL（全脑和脑干；校正，p < 0.01）进行了 2 种分析，以确定与基线和 SCM 刺激相比，nVNS 是否在脑干和前脑中激活了迷走神经投射。
与基线和对照（SCM）刺激相比，nVNS 显著激活了初级迷走神经投射，包括：孤束核（迷走传入神经的主要中枢中继）、臂旁核、初级感觉皮层和脑岛。基底神经节和额叶皮层的区域也被显著激活。在海马体、视觉皮层和三叉神经脊核中发现了去激活。
本研究结果为人类提供了证据，表明通过经皮刺激颈部前外侧表面可以非侵入性地触及迷走神经传入纤维，该表面覆盖了神经的走行，这提示了一种刺激迷走神经传入的替代且可行的方法。
