Cognitive Neuroscience Laboratory, Rehabilitation Institute of Chicago, Chicago, IL, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
Cognitive Neuroscience Laboratory, Rehabilitation Institute of Chicago, Chicago, IL, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
Brain Stimul. 2016 Sep-Oct;9(5):720-729. doi: 10.1016/j.brs.2016.04.015. Epub 2016 Apr 22.
Response inhibition is a critical executive function, enabling the adaptive control of behavior in a changing environment. The inferior frontal cortex (IFC) is considered to be critical for response inhibition, leading researchers to develop transcranial direct current stimulation (tDCS) montages attempting to target the IFC and improve inhibitory performance. However, conventional tDCS montages produce diffuse current through the brain, making it difficult to establish causality between stimulation of any one given brain region and resulting behavioral changes. Recently, high-definition tDCS (HD-tDCS) methods have been developed to target brain regions with increased focality relative to conventional tDCS.
Remarkably few studies have utilized HD-tDCS to improve cognitive task performance, however, and no study has directly compared the behavioral effects of HD-tDCS to conventional tDCS.
In the present study, participants received either HD-tDCS or conventional tDCS to the IFC during performance of a response inhibition task (stop-signal task, SST) or a control task (choice reaction time task, CRT). A third group of participants completed the same behavioral protocols, but received tDCS to a control site (mid-occipital cortex). Post-stimulation improvement in SST performance was analyzed as a function of tDCS group and the task performed during stimulation using both conventional and Bayesian parameter estimation analyses.
Bayesian estimation of the effects of HD- and conventional tDCS to IFC relative to control site stimulation demonstrated enhanced response inhibition for both conditions. No improvements were found after control task (CRT) training in any tDCS condition.
Results support the use of both HD- and conventional tDCS to the IFC for improving response inhibition, providing empirical evidence that HD-tDCS can be used to facilitate performance on an executive function task.
反应抑制是一种关键的执行功能，使行为能够在不断变化的环境中进行自适应控制。下额前皮质（IFC）被认为对反应抑制至关重要，这促使研究人员开发经颅直流电刺激（tDCS）模式，试图靶向 IFC 并改善抑制性能。然而，传统的 tDCS 模式会在大脑中产生弥散电流，因此很难确定刺激任何一个特定脑区与导致的行为变化之间的因果关系。最近，已经开发出高清 tDCS（HD-tDCS）方法来提高相对于传统 tDCS 的大脑区域的靶向性。
然而，利用 HD-tDCS 来改善认知任务表现的研究很少，并且没有研究直接比较 HD-tDCS 与传统 tDCS 的行为效果。
在本研究中，参与者在执行反应抑制任务（停止信号任务，SST）或控制任务（选择反应时任务，CRT）期间接受 IFC 的 HD-tDCS 或传统 tDCS。第三组参与者完成了相同的行为方案，但接受了对控制部位（中枕叶皮质）的 tDCS。使用传统和贝叶斯参数估计分析，根据 tDCS 组和刺激期间执行的任务，分析刺激后 SST 性能的改善。
相对于控制部位刺激，HD-tDCS 和传统 tDCS 对 IFC 的影响的贝叶斯估计表明，两种情况下的反应抑制都得到了增强。在任何 tDCS 条件下，控制任务（CRT）训练后都没有发现改善。
结果支持使用 HD-tDCS 和传统 tDCS 对 IFC 进行刺激以改善反应抑制，为 HD-tDCS 可用于促进执行功能任务的表现提供了经验证据。
