Friehs Maximilian A, Frings Christian
Cognitive Psychology, University of Trier, Trier, Germany.
Cogn Affect Behav Neurosci. 2019 Oct;19(5):1129-1142. doi: 10.3758/s13415-019-00740-0.
Transcranial direct current stimulation (tDCS) is a noninvasive method of modulating human brain activity and potentially alters performance in cognitive tasks. Often it is assumed that effects of tDCS modulation depend on the polarity-anodal stimulation typically boost cognitive processes whereas cathodal stimulation hampers them. While most tDCS research focusses on the effects of anodal stimulation, cathodal tDCS effects are underexplored. In the present study, cathodal tDCS over the right dorsolateral prefrontal cortex (rDLPFC) was used to potentially hamper the response inhibition process as measured by the stop-signal task (SST). A 9 cm cathode was always positioned over the rDLPFC while the 35 cm anode was placed over the left deltoid. We contrasted a cathodal stimulation condition (that is assumed to reduce neural processing) with sham stimulation and expected a decrease in SST performance after cathodal tDCS, as evidenced by an increase in stop-signal reaction time (SSRT). In a sample of N = 45 healthy adults, a significant Time × tDCS condition interaction emerged, indicating an increase in SSRT after cathodal tDCS. In a recent study by Friehs and Frings (Journal of Experimental Psychology: Human Perception and Performance, 2018), using a similar study design and stimulation protocol, single-session anodal tDCS over the rDLPFC was used to enhance SST performance as indicated by an acceleration of SSRT. In concert, these results suggest that response inhibition is tied to the neural state of the rDLPFC.
经颅直流电刺激（tDCS）是一种调节人类大脑活动的非侵入性方法，可能会改变认知任务中的表现。人们通常认为，tDCS调节的效果取决于极性——阳极刺激通常会促进认知过程，而阴极刺激则会阻碍认知过程。虽然大多数tDCS研究集中在阳极刺激的效果上，但阴极tDCS的效果却未得到充分探索。在本研究中，通过停止信号任务（SST）测量，对右侧背外侧前额叶皮层（rDLPFC）进行阴极tDCS，以潜在地阻碍反应抑制过程。一个9厘米的阴极始终放置在rDLPFC上方，而35厘米的阳极则放置在左三角肌上方。我们将阴极刺激条件（假定会减少神经处理）与假刺激进行了对比，并预期阴极tDCS后SST表现会下降，这表现为停止信号反应时间（SSRT）增加。在N = 45名健康成年人的样本中，出现了显著的时间×tDCS条件交互作用，表明阴极tDCS后SSRT增加。在Friehs和Frings最近的一项研究（《实验心理学杂志：人类感知与表现》，2018年）中，使用了类似的研究设计和刺激方案，对rDLPFC进行单节段阳极tDCS以提高SST表现，这表现为SSRT加速。总之，这些结果表明反应抑制与rDLPFC的神经状态有关。
