Kasanov Dauren, Dorogina Olga, Mushtaq Faisal, Pavlov Yuri G
Ural Federal University.
University of Leeds.
J Cogn Neurosci. 2025 Mar 1;37(3):641-656. doi: 10.1162/jocn_a_02269.
There is an extensive body of research showing a significant relationship between frontal midline theta activity in the 4- to 8-Hz range and working memory (WM) performance. Transcranial alternating current stimulation (tACS) is recognized for inducing lasting changes in brain oscillatory activity. Across two experiments, we tested whether WM could be improved through tACS of dorsomedial PFC and ACC, by affecting executive control networks associated with frontal midline theta. In Experiment 1, after either a 20-min verum or sham stimulation applied to Fpz-CPz at 1 mA and 6 Hz, 31 participants performed WM tasks, while EEG was recorded. The tasks required participants to either mentally manipulate memory items or retain them in memory as they were originally presented. No significant effects were observed in behavioral performance, and we found no change in theta activity during rest and task after stimulation. However, alpha activity during retention or manipulation of information in WM was less strongly enhanced during the delay period after verum stimulation as compared with sham. In Experiment 2 (n = 25), tACS was administered during the task in two separate sessions. Here, we changed the order of the stimulation blocks: A 25-min task block was either accompanied first by sham stimulation and then by verum stimulation, or vice versa. Again, we found no improvements in WM through either tACS after-effects or online stimulation. Taken together, our results demonstrate that theta frequency tACS applied at the midline is not an effective method for enhancing WM.
有大量研究表明，4至8赫兹范围内的额中线θ活动与工作记忆（WM）表现之间存在显著关系。经颅交流电刺激（tACS）因能引起脑振荡活动的持久变化而得到认可。在两项实验中，我们测试了通过对背内侧前额叶皮质和前扣带回进行tACS刺激，是否能通过影响与额中线θ相关的执行控制网络来改善工作记忆。在实验1中，31名参与者在以1毫安和6赫兹对Fpz-CPz施加20分钟的真刺激或假刺激后，进行工作记忆任务，同时记录脑电图。这些任务要求参与者要么在脑海中操纵记忆项目，要么按最初呈现的样子将它们保留在记忆中。行为表现未观察到显著影响，并且我们发现在刺激后的休息和任务期间，θ活动没有变化。然而，与假刺激相比，在真刺激后的延迟期，工作记忆中信息保留或操纵期间的α活动增强程度较弱。在实验2（n = 25）中，在任务期间分两个单独阶段进行tACS刺激。在这里，我们改变了刺激块的顺序：一个25分钟的任务块要么首先伴随假刺激，然后伴随真刺激，反之亦然。同样，我们发现无论是通过tACS后效应还是在线刺激，工作记忆都没有改善。综合来看，我们的结果表明，在中线施加的θ频率tACS不是增强工作记忆的有效方法。
