Brunyé Tad T, Cantelon Julie, Holmes Amanda, Taylor Holly A, Mahoney Caroline R
US. Army Natick Soldier Research, Development, and Engineering Center, RDNS-SEW-THC, 15 Kansas St., Natick, MA, USA; Tufts University, Department of Psychology, 490 Boston Ave., Medford, MA, USA.
US. Army Natick Soldier Research, Development, and Engineering Center, RDNS-SEW-THC, 15 Kansas St., Natick, MA, USA; Tufts University, Department of Psychology, 490 Boston Ave., Medford, MA, USA.
Brain Stimul. 2014 Nov-Dec;7(6):832-5. doi: 10.1016/j.brs.2014.09.015. Epub 2014 Oct 16.
Cutaneous sensations at electrode sites during the administration of direct current brain stimulation may inadvertently influence participants' subjective experience and task performance.
The present study evaluated the utility of a methodological variation that substitutes sham administration with very low intensity (0.5 mA) current delivery.
We used a 4 × 1 high-definition ring electrode transcranial direct current (HD-tDCS) system to target the left dorsolateral prefrontal cortex (Brodmann's Area 9). Four stimulation conditions were compared in a repeated-measures design: sham 2.0 mA and 0.5 mA intensity, versus active 2.0 mA and 0.5 mA intensity. During stimulation participants performed a cognitive interference task that activates the cingulo-frontal-parietal network, and periodically provided perceived sensation ratings.
We demonstrate that a relatively low intensity control condition attenuates otherwise large differences in perceived sensation between active and sham conditions. Critically, behavioral task differences maintained between the two active conditions.
A low intensity control stimulation condition may prove a viable methodological alternative to conventional sham techniques used in repeated-measures designs, though important limitations are discussed.
在进行直流电刺激大脑时，电极部位的皮肤感觉可能会无意中影响参与者的主观体验和任务表现。
本研究评估了一种方法学变体的效用，该变体用极低强度（0.5毫安）的电流输送替代假刺激。
我们使用一个4×1高清环形电极经颅直流电（HD-tDCS）系统靶向左侧背外侧前额叶皮层（布罗德曼9区）。在重复测量设计中比较了四种刺激条件：假刺激2.0毫安和0.5毫安强度，与主动刺激2.0毫安和0.5毫安强度。在刺激过程中，参与者执行一项激活扣带回-额叶-顶叶网络的认知干扰任务，并定期提供感觉感知评分。
我们证明，相对低强度的对照条件减弱了主动刺激和假刺激条件下原本在感觉感知上的巨大差异。关键的是，两种主动刺激条件之间的行为任务差异依然存在。
低强度对照刺激条件可能是重复测量设计中使用的传统假刺激技术的一种可行的方法学替代方案，不过也讨论了其重要局限性。
