Henry T R, Bakay R A, Votaw J R, Pennell P B, Epstein C M, Faber T L, Grafton S T, Hoffman J M
Department of Neurology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Epilepsia. 1998 Sep;39(9):983-90. doi: 10.1111/j.1528-1157.1998.tb01448.x.
Left cervical vagus nerve stimulation (VNS) decreases complex partial seizures (CPS) by unknown mechanisms of action. We hypothesized that therapeutic VNS alters synaptic activities at vagal afferent terminations and in sites that receive polysynaptic projections from these medullary nuclei.
Ten patients with partial epilepsy underwent positron emission tomographic (PET) measurements of cerebral blood flow (BF) three times before and three times during VNS. Parameters for VNS were at high levels for 5 patients and at low levels for 5. Resting BF measurements were subtracted from measurements during VNS in each subject. Subtraction data were averaged in each of 2 groups of 5 patients. t Tests were applied to BF changes in brain regions that receive vagal afferents and projections (significant at p < 0.05, corrected for repeated measures).
In both the low- and high-stimulation groups during VNS, brain BF was (a) increased in the rostral, dorsal-central medulla; (b) increased in the right postcentral gyrus, (c) increased bilaterally in the hypothalami, thalami, and insular cortices, and in cerebellar hemispheres inferiorly; and (d) decreased bilaterally in hippocampus, amygdala, and posterior cingulate gyri. The high-stimulation group had greater volumes of activation and deactivation sites.
Our findings suggest that left cervical VNS acutely increases synaptic activity in structures directly innervated by central vagal structures and areas that process left-sided somatosensory information, but VNS also acutely alters synaptic activity in multiple limbic system structures bilaterally. These findings may reflect sites of therapeutic actions of VNS.
左侧颈迷走神经刺激（VNS）通过未知的作用机制减少复杂部分性发作（CPS）。我们推测治疗性VNS会改变迷走神经传入神经末梢以及接受来自这些延髓核多突触投射部位的突触活动。
10例部分性癫痫患者在VNS治疗前和治疗期间进行了3次正电子发射断层扫描（PET）测量脑血流量（BF）。5例患者的VNS参数为高水平，5例为低水平。在每个受试者中，用VNS期间的测量值减去静息BF测量值。将5例患者分为的2组中的每组减法数据进行平均。对接受迷走神经传入和投射的脑区的BF变化进行t检验（p<0.05时有显著性差异，经重复测量校正）。
在VNS治疗期间，低刺激组和高刺激组的脑BF均有以下变化：（a）延髓头端背中部增加；（b）右侧中央后回增加；（c）下丘脑、丘脑、岛叶皮质以及小脑半球双侧增加；（d）海马、杏仁核和后扣带回双侧减少。高刺激组的激活和失活部位体积更大。
我们的研究结果表明，左侧颈VNS可急性增加由中枢迷走神经结构直接支配的结构以及处理左侧躯体感觉信息区域的突触活动，但VNS也会急性改变双侧多个边缘系统结构的突触活动。这些发现可能反映了VNS的治疗作用部位。
