School of Psychology, Murdoch University, Western Australia, Australia; Centre for Healthy Ageing, Health Futures Institute, Murdoch University, Western Australia, Australia; Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.
School of Psychology, Murdoch University, Western Australia, Australia.
Neuropsychologia. 2023 Dec 15;191:108737. doi: 10.1016/j.neuropsychologia.2023.108737. Epub 2023 Nov 22.
The efficacy of transcranial alternating current stimulation (tACS) is thought to be brain state-dependent, such that tACS during task performance would be hypothesised to offer greater potential for improving performance compared to tACS at rest. However, to date, no empirical study has tested this postulation. The current study compared the effects of dual-site beta tACS applied during a stop signal task (online) to the effects of the same tACS protocol applied prior to the task (offline) and a sham control stimulation in 53 young, healthy adults (32 female; 18-35 yrs). The right inferior frontal gyrus (rIFG) and centre (midline) of the pre-supplementary motor area (preSMA), which are thought to play critical roles in action cancellation, were simultaneously stimulated, sending phase-synchronised stimulation for 15 min with the aim of increasing functional connectivity. The offline group showed significant within-group improvement in response inhibition without showing overt task-related changes in functional connectivity measured with EEG connectivity analysis, suggesting offline tACS is efficacious in inducing behavioural changes potentially via a post-stimulation early plasticity mechanism. In contrast, neither the online nor sham group showed significant improvements in response inhibition. However, EEG connectivity analysis revealed significantly increased task-related functional connectivity following online stimulation and a medium effect size observed in correlation analyses suggested that an increase in functional connectivity in the beta band at rest was potentially associated with an improvement in response inhibition. Overall, the results indicate that both online and offline dual-site beta tACS can be beneficial in improving inhibitory control via distinct underlying mechanisms.
经颅交流电刺激（tACS）的疗效被认为是依赖于大脑状态的，例如，与在休息时进行 tACS 相比，在任务执行期间进行 tACS 可能更有潜力提高任务表现。然而，迄今为止，没有实证研究检验过这一假设。本研究比较了在停止信号任务期间施加的双部位β tACS（在线）与在任务之前施加的相同 tACS 方案（离线）以及假刺激控制在 53 名年轻健康成年人（32 名女性；18-35 岁）中的效果。右额下回（rIFG）和预备运动区（preSMA）中心（中线）被同时刺激，发送相位同步刺激 15 分钟，目的是增加功能连接。离线组在反应抑制方面表现出显著的组内改善，而在 EEG 连通性分析中没有表现出明显的与任务相关的功能连通性变化，这表明离线 tACS 通过刺激后的早期可塑性机制在诱导行为变化方面是有效的。相比之下，在线组和假刺激组在反应抑制方面均未显示出显著改善。然而，EEG 连通性分析显示在线刺激后任务相关的功能连通性显著增加，相关分析中观察到的中等效应大小表明，在静息状态下β 波段的功能连通性增加可能与反应抑制的改善有关。总体而言，这些结果表明，在线和离线双部位β tACS 都可以通过不同的潜在机制有益于改善抑制控制。
