Mansouri Farrokh, Shanbour Alaa, Mazza Frank, Fettes Peter, Zariffa José, Downar Jonathan
Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
Department of Psychiatry, Central Michigan University, Mount Pleasant, MI, United States.
Front Neurosci. 2019 Nov 14;13:1181. doi: 10.3389/fnins.2019.01181. eCollection 2019.
Non-invasive brain stimulation (NIBS) is emerging as a robust treatment alternative for major depressive disorder, with a potential for achieving higher remission rates by providing targeted stimulation to underlying brain networks, such as the salience network (SN). Growing evidence suggests that these therapeutic effects are dependent on the frequency and phase synchrony between SN oscillations and stimulation as well as the task-specific state of the SN during stimulation. However, the development of phase-synchronized non-invasive stimulation has proved challenging until recently. Here, we use a phase-locked pulsed brain stimulation approach to study the effects of two NIBS methods: transcranial alternating current stimulation (tACS) versus phase-locked transcranial pulsed current stimulation (tPCS), on the SN during an SN activating task. 20 healthy volunteers participated in the study. Each volunteer partook in four sessions, receiving one stimulation type at random (theta-tACS, peak tPCS, trough tPCS or sham) while undergoing a learning game, followed by an unstimulated test based on learned material. Each session lasted approximately 1.5 h, with an interval of at least 2 days to allow for washout and to avoid cross-over effects. Our results showed no statistically significant effect of stimulation on the event related potential (ERP) recordings, resting electroencephalogram (EEG), and the performance of the volunteers. While stimulation effects were not apparent in this study, the nominal performance of the phase-locking algorithm offers a technical foundation for further research in determining effective stimulation paradigms and conditions. Specifically, future work should investigate stronger stimulation and true task-specific stimulation of SN nodes responsible for the task as well as their recording. If refined, NIBS could offer an effective, homebased treatment option.
非侵入性脑刺激（NIBS）正在成为治疗重度抑郁症的一种有效替代方法，通过对潜在脑网络（如突显网络（SN））进行靶向刺激，有可能实现更高的缓解率。越来越多的证据表明，这些治疗效果取决于SN振荡与刺激之间的频率和相位同步，以及刺激期间SN的任务特定状态。然而，直到最近，相位同步非侵入性刺激的发展一直具有挑战性。在这里，我们使用锁相脉冲脑刺激方法来研究两种NIBS方法：经颅交流电刺激（tACS）与锁相经颅脉冲电流刺激（tPCS），在SN激活任务期间对SN的影响。20名健康志愿者参与了这项研究。每位志愿者参加四个疗程，在进行学习游戏时随机接受一种刺激类型（θ-tACS、峰值tPCS、谷值tPCS或假刺激），然后根据所学材料进行无刺激测试。每个疗程持续约1.5小时，间隔至少2天，以便进行洗脱并避免交叉效应。我们的结果显示，刺激对事件相关电位（ERP）记录、静息脑电图（EEG）和志愿者表现没有统计学上的显著影响。虽然在本研究中刺激效果不明显，但锁相算法的标称性能为进一步研究确定有效刺激范式和条件提供了技术基础。具体而言，未来的工作应研究对负责该任务的SN节点进行更强的刺激和真正的任务特定刺激以及对它们的记录。如果得到改进，NIBS可以提供一种有效的、基于家庭的治疗选择。
