Clinical Neurotechnology Laboratory, Department of Psychiatry and Neurosciences, Charité Campus Mitte (CCM), Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
Precision Neuroscience and Neuromodulation Program & Network Control Laboratory, Gordon Center for Medical Imaging, Massachusetts General Hospital & Harvard Medical School, Boston, MA, USA.
Neuroimage. 2023 Jul 15;275:120187. doi: 10.1016/j.neuroimage.2023.120187. Epub 2023 May 23.
Transcranial alternating current stimulation (tACS) can influence perception and behavior, with recent evidence also highlighting its potential impact in clinical settings, but its underlying mechanisms are poorly understood. Behavioral and indirect physiological evidence indicates that phase-dependent constructive and destructive interference between the applied electric field and brain oscillations at the stimulation frequency may play an important role, but in vivo validation during stimulation was unfeasible because stimulation artifacts impede single-trial assessment of brain oscillations during tACS. Here, we attenuated stimulation artifacts to provide evidence for phase-dependent enhancement and suppression of visually evoked steady state responses (SSR) during amplitude-modulated tACS (AM-tACS). We found that AM-tACS enhanced and suppressed SSR by 5.77 ± 2.95%, while it enhanced and suppressed corresponding visual perception by 7.99 ± 5.15%. While not designed to investigate the underlying mechanisms of this effect, our study suggests feasibility and superiority of phase-locked (closed-loop) AM-tACS over conventional (open-loop) AM-tACS to purposefully enhance or suppress brain oscillations at specific frequencies.
经颅交流电刺激（tACS）可以影响感知和行为，最近的证据也强调了其在临床环境中的潜在影响，但它的潜在机制仍不清楚。行为和间接生理证据表明，施加的电场与刺激频率下的脑振荡之间的相位相关的建设性和破坏性干扰可能起着重要作用，但由于刺激伪影阻碍了 tACS 期间脑振荡的单次试验评估，因此在体内验证是不可行的。在这里，我们减弱了刺激伪影，为在幅度调制 tACS（AM-tACS）期间相位相关的增强和抑制视觉诱发电稳态反应（SSR）提供了证据。我们发现 AM-tACS 增强和抑制 SSR 的幅度分别为 5.77±2.95%，而它增强和抑制相应视觉感知的幅度分别为 7.99±5.15%。虽然我们的研究不是为了探讨这种效果的潜在机制，但它表明，与传统的（开环）AM-tACS 相比，相位锁定（闭环）AM-tACS 具有可行性和优越性，可以有针对性地增强或抑制特定频率的脑振荡。
