Huang Peihan J, Arif Yasra, Son Jake J, John Jason A, Rempe Maggie P, McDonald Kellen M, Webert Lauren K, Garrison Grant M, Okelberry Hannah J, Kress Kennedy A, Petro Nathan M, Wilson Tony W
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA; Department of Pharmacology & Neuroscience, Creighton University, Omaha, NE, USA.
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA.
Neuroimage. 2025 Jul 29;318:121407. doi: 10.1016/j.neuroimage.2025.121407.
Verbal working memory (WM) is a critical cognitive construct supporting a broad range of daily functions. Neuroimaging studies have highlighted the involvement of prefrontal-occipital circuitry in WM, but specific regional contributions and possible laterality effects remain unclear. Transcranial direct current stimulation (tDCS) is an emerging technique that noninvasively modulates the excitability of neural populations, with studies showing stimulation effects on both local and distant but connected cortices. Herein, we utilized a novel dual-montage, high-definition tDCS (HD-tDCS) approach to evaluate the impact on functional brain dynamics and WM performance. Forty-five healthy adults underwent dual-montage HD-tDCS with 2.0 mA anodal stimulation applied over the midline occipital cortices and either the left or right dorsolateral prefrontal cortices (DLPFC) concurrently, or sham to both sites during three sessions. Following stimulation, participants completed a verbal WM task during magnetoencephalography (MEG). Whole-brain, voxel-wise maps were subjected to 1 × 3 repeated measure ANOVAs to probe stimulation effects. We found that left DLPFC-occipital stimulation induced stronger theta responses in the left superior temporal cortices, left supramarginal gyrus, left angular gyrus, and the right parietal cortices, while attenuated alpha responses were observed in the bilateral parietal cortices following right compared to left DLPFC-occipital stimulation and sham. Additionally, both active stimulation montages modulated oscillatory responses in the bilateral inferior frontal, the right lateral occipital cortices and other critical WM network regions during the encoding and maintenance phases. In conclusion, our results show that dual-montage anodal HD-tDCS differentially modulates spectrally and temporally distinct oscillatory responses, suggesting clear functional dissociations between left and right prefrontal regions during WM processing. These findings highlight the potential of tDCS in advancing our understanding of the unique contribution of each region in the network, which long-term could inform clinical interventions.
言语工作记忆（WM）是一种关键的认知结构，支持广泛的日常功能。神经影像学研究强调了前额叶 - 枕叶回路在工作记忆中的参与，但具体的区域贡献和可能的偏侧性效应仍不清楚。经颅直流电刺激（tDCS）是一种新兴技术，可无创地调节神经群体的兴奋性，研究表明其对局部和远距离但相互连接的皮层均有刺激作用。在此，我们采用了一种新颖的双电极、高清tDCS（HD - tDCS）方法来评估其对大脑功能动态和工作记忆表现的影响。45名健康成年人在三个疗程中接受了双电极HD - tDCS，以2.0 mA的阳极刺激同时施加于枕叶中央皮质以及左侧或右侧背外侧前额叶皮质（DLPFC），或对两个部位进行假刺激。刺激后，参与者在脑磁图（MEG）期间完成一项言语工作记忆任务。对全脑体素水平的图谱进行1×3重复测量方差分析以探究刺激效果。我们发现，左侧DLPFC - 枕叶刺激在左侧颞上回、左侧缘上回、左侧角回和右侧顶叶皮质诱发了更强的θ反应，而与左侧DLPFC - 枕叶刺激及假刺激相比，右侧DLPFC - 枕叶刺激后双侧顶叶皮质观察到α反应减弱。此外，在编码和维持阶段，两种主动刺激电极配置均调节了双侧额下回、右侧枕叶外侧皮质和其他关键工作记忆网络区域的振荡反应。总之，我们的结果表明，双电极阳极HD - tDCS以不同方式调节频谱和时间上不同的振荡反应，表明在工作记忆处理过程中左右前额叶区域之间存在明显的功能分离。这些发现突出了tDCS在推进我们对网络中每个区域独特贡献的理解方面的潜力，从长远来看可能为临床干预提供信息。
