Department of Functional Neurosurgery and Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China.
Department of Magnetoencephalography, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China.
Brain Connect. 2023 Feb;13(1):51-59. doi: 10.1089/brain.2022.0011. Epub 2022 Sep 15.
Vagus nerve stimulation (VNS) has been a neuromodulatory option for treating drug-resistant epilepsy (DRE), but its mechanism remains unclear. To obtain insight into the mechanism by which VNS reduces epileptic seizures, the immediate effects of VNS in brain networks of DRE patients were investigated when the patients' vagal nerve stimulators were turned on. The brain network properties of 14 DRE patients with a vagal nerve stimulator and 14 healthy controls were evaluated using magnetoencephalography recordings for 6 main frequency bands. Compared with healthy controls, DRE patients exhibited significant increases in functional connectivity in the theta, alpha, beta, and gamma bands and significant reductions in the small-world measure in the theta and beta bands. During periods when patients' vagal nerve stimulators were turned on, DRE patients showed significant reductions in functional connectivity in the theta and alpha bands and a significant increase in the small-world measure in the theta band when compared with periods when patients' vagal nerve stimulators were turned off. Our results indicate that the brain networks of DRE patients were pathologically hypersynchronous and instantaneous VNS can decrease the synchronization of brain networks of epileptic patients, which might play a key role in the mechanism by which VNS reduces epileptic seizures. In the theta band, instantaneous VNS can increase the network efficiency of DRE patients, and the increment in network efficiency may be helpful for improving brain cognitive function in epileptic patients. Impact statement For the first time, we investigated the immediate effects of vagus nerve stimulation (VNS) in the brain networks of drug-resistant epilepsy patients using magnetoencephalography. Our results show that instantaneous VNS can decrease the hypersynchronization of epileptic networks and increase the network efficiency of epileptic patients. Our results are helpful in understanding the mechanism of action by which VNS reduces epileptic seizures and improves the cognitive function in epileptic patients and the brain network reorganization caused by long-term VNS.
迷走神经刺激（VNS）一直是治疗耐药性癫痫（DRE）的神经调节选择，但它的机制尚不清楚。为了深入了解 VNS 减少癫痫发作的机制，当 DRE 患者的迷走神经刺激器开启时，研究了 VNS 对 DRE 患者大脑网络的即时影响。使用脑磁图记录对 14 名带有迷走神经刺激器的 DRE 患者和 14 名健康对照者的大脑网络特性进行了评估，共评估了 6 个主要频段。与健康对照组相比，DRE 患者在θ、α、β和γ频段的功能连接明显增加，在θ和β频段的小世界度量明显降低。当患者的迷走神经刺激器开启时，与患者的迷走神经刺激器关闭时相比，DRE 患者在θ和α频段的功能连接明显降低，而在θ频段的小世界度量明显增加。我们的研究结果表明，DRE 患者的大脑网络病理性过度同步，即时 VNS 可降低癫痫患者的网络同步性，这可能在 VNS 减少癫痫发作的机制中发挥关键作用。在θ频段，即时 VNS 可以增加 DRE 患者的网络效率，网络效率的提高可能有助于改善癫痫患者的大脑认知功能。影响说明我们首次使用脑磁图研究了迷走神经刺激（VNS）对耐药性癫痫患者大脑网络的即时影响。我们的研究结果表明，即时 VNS 可以降低癫痫网络的过度同步性，并提高癫痫患者的网络效率。我们的研究结果有助于理解 VNS 减少癫痫发作和改善癫痫患者认知功能以及长期 VNS 引起的大脑网络重组的作用机制。
