Transcranial direct current stimulation over right posterior parietal cortex changes prestimulus alpha oscillation in visual short-term memory task
Transcranial direct current stimulation over right posterior parietal cortex changes prestimulus alpha oscillation in visual short-term memory task
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DOI：
10.1016/j.neuroimage.2014.04.069
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发表时间：
2014-09-01
期刊：
影响因子：
5.7
通讯作者：
Juan, Chi-Hung
中科院分区：
文献类型：
--
作者：
Hsu, Tzu-Yu;Tseng, Philip;Juan, Chi-Hung
α带活动随注意力水平的变化而变化，最近的研究表明这种振荡与后顶叶皮层的活动有关。本研究表明，通过带正电荷的电流通过颅骨，人为地提高顶叶活动，可以迅速而毫不费力地改变人的刺激前α功率，并改善视觉短期记忆（VSTM）任务的后续表现。然而，这种对阿尔法能量和行为表现的调节依赖于人们的自然VSTIV能力，因此只有表现不佳的人才能从刺激中受益，而表现优异的人则没有。这种行为的两分法是由顶枕区周围的刺激前α功率来解释的，表现不佳的人表现出刺激前α功率的下降，这表明在当前的范式中注意力部署得到了改善，而表现优异的人没有从tDCS中受益，因为他们在刺激前后表现出同样低的刺激前α功率。综上所述，这些结果表明，刺激前的α功率，特别是在表现不佳的情况下，可以通过阳极刺激来调节，并改变随后的VSTM性能/容量。因此，在刺激开始前测量α可能与测量其他与vstm相关的电生理成分一样重要，如注意分配和记忆容量相关的成分（即N2后对侧，N2pc或对侧延迟活动，CDA）。此外，低VST1V表现者可能不仅仅是VSTM能力差，而且还有广泛的注意机制，刺激前α可能是理解VSTM个体差异本质的有用工具。(C) 2014爱思唯尔公司版权所有。
Alpha band activity changes accompanied with the level attentional state, and recent studies suggest that suc' oscillation is associated with activities in the posterior parietal cortex. Here we show that artificially elevating parietal activity via positively-charged electric current through the skull can rapidly and effortlessly change people'prestimulus alpha power and improve subsequent performance on a visual short-term memory (VSTM) task. This modulation of alpha power and behavioral performance, however, is dependent on people's natural VSTIV capability such that only the low performers benefitted from the stimulation, whereas high performers dic not. This behavioral dichotomy is accounted by prestimulus alpha powers around the parieto-occipital regions low performers showed decreased prestimulus alpha power, suggesting improvement in attention deploymen in the current paradigm, whereas the high performers did not benefit from tDCS as they showed equally-low prestimulus alpha power before and after the stimulation. Together, these results suggest that prestimulus alpha power, especially in low performers, can be modulated by anodal stimulation and alter subsequen VSTM performance/capacity. Thus, measuring alpha before stimulus onset may be as important as measuring other VSTM-related electrophysiological components such as attentional allocation and memory capacity relate components (i.e. N2 posterior-contralateral, N2pc, or contralateral delay activity, CDA). In addition, low VST1V performers perhaps do not suffer not only from poor VSTM capacity, but also from broad attentional mechanisms and prestimulus alpha may be an useful tool in understanding the nature of individual differences in VSTM. (C) 2014 Elsevier Inc. All rights reserved.