Santander Tyler, Leslie Sara, Li Luna J, Skinner Henri E, Simonson Jessica M, Sweeney Patrick, Deen Kaitlyn P, Miller Michael B, Brunye Tad T
Institute for Collaborative Biotechnologies, University of California, Santa Barbara, Santa Barbara, CA, United States.
Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States.
Front Hum Neurosci. 2024 Jul 2;18:1305446. doi: 10.3389/fnhum.2024.1305446. eCollection 2024.
Transcranial direct current stimulation (tDCS) administers low-intensity direct current electrical stimulation to brain regions via electrodes arranged on the surface of the scalp. The core promise of tDCS is its ability to modulate brain activity and affect performance on diverse cognitive functions (affording inferences regarding regional brain activity and behavior), but the optimal methodological parameters for maximizing behavioral effects remain to be elucidated. Here we sought to examine the effects of 10 stimulation and experimental design factors across a series of five cognitive domains: motor performance, visual search, working memory, vigilance, and response inhibition. The objective was to identify a set of optimal parameter settings that consistently and reliably maximized the behavioral effects of tDCS within each cognitive domain.
We surveyed tDCS effects on these various cognitive functions in healthy young adults, ultimately resulting in 721 effects across 106 published reports. Hierarchical Bayesian meta-regression models were fit to characterize how (and to what extent) these design parameters differentially predict the likelihood of positive/negative behavioral outcomes.
Consistent with many previous meta-analyses of tDCS effects, extensive variability was observed across tasks and measured outcomes. Consequently, most design parameters did not confer consistent advantages or disadvantages to behavioral effects-a domain-general model suggested an advantage to using within-subjects designs (versus between-subjects) and the tendency for cathodal stimulation (relative to anodal stimulation) to produce reduced behavioral effects, but these associations were scarcely-evident in domain-specific models.
These findings highlight the urgent need for tDCS studies to more systematically probe the effects of these parameters on behavior to fulfill the promise of identifying causal links between brain function and cognition.
经颅直流电刺激（tDCS）通过置于头皮表面的电极，对脑区施加低强度直流电刺激。tDCS的核心前景在于其调节脑活动并影响多种认知功能表现的能力（从而为推断脑区活动与行为之间的关系提供依据），但对于使行为效应最大化的最佳方法参数仍有待阐明。在此，我们试图研究10个刺激和实验设计因素在运动表现、视觉搜索、工作记忆、警觉性和反应抑制这五个认知领域中的作用。目的是确定一组最佳参数设置，在每个认知领域内持续且可靠地使tDCS的行为效应最大化。
我们调查了tDCS对健康年轻成年人这些不同认知功能的影响，最终在106篇已发表报告中得到721个效应。采用分层贝叶斯元回归模型来描述这些设计参数如何（以及在何种程度上）差异地预测正向/负向行为结果的可能性。
与之前许多关于tDCS效应的元分析一致，在任务和测量结果中观察到广泛的变异性。因此，大多数设计参数并未给行为效应带来一致的优势或劣势——一个通用模型表明采用被试内设计（相对于被试间设计）具有优势，且阴极刺激（相对于阳极刺激）往往会产生较小的行为效应，但这些关联在特定领域模型中几乎不明显。
这些发现凸显了tDCS研究迫切需要更系统地探究这些参数对行为的影响，以实现确定脑功能与认知之间因果联系的前景。
