Schroeder Philipp Alexander, Pfister Roland, Kunde Wilfried, Nuerk Hans-Christoph, Plewnia Christian
University of Tübingen.
University of Würzburg.
J Cogn Neurosci. 2016 Nov;28(11):1737-1748. doi: 10.1162/jocn_a_01001. Epub 2016 Jun 22.
Cognitive conflicts and distractions by task-irrelevant information often counteract effective and goal-directed behaviors. In some cases, conflicting information can even emerge implicitly, without an overt distractor, by the automatic activation of mental representations. For instance, during number processing, magnitude information automatically elicits spatial associations resembling a mental number line. This spatial-numerical association of response codes (SNARC) effect can modulate cognitive-behavioral performance but is also highly flexible and context-dependent, which points toward a critical involvement of working memory functions. Transcranial direct current stimulation to the PFC, in turn, has been effective in modulating working memory-related cognitive performance. In a series of experiments, we here demonstrate that decreasing activity of the left PFC by cathodal transcranial direct current stimulation consistently and specifically eliminates implicit cognitive conflicts based on the SNARC effect, but explicit conflicts based on visuospatial distraction remain unaffected. This dissociation is polarity-specific and appears unrelated to functional magnitude processing as classified by regular numerical distance effects. These data demonstrate a causal involvement of the left PFC in implicit cognitive conflicts based on the automatic activation of spatial-numerical processing. Corroborating the critical interaction of brain stimulation and neurocognitive functions, our findings suggest that distraction from goal-directed behavior by automatic activation of implicit, task-irrelevant information can be blocked by the inhibition of prefrontal activity.
认知冲突以及与任务无关的信息所造成的干扰，常常会抵消有效的目标导向行为。在某些情况下，相互冲突的信息甚至可能在没有明显干扰物的情况下，通过心理表征的自动激活而隐性出现。例如，在数字处理过程中，数量信息会自动引发类似于心理数字线的空间联想。这种反应编码的空间数字关联（SNARC）效应能够调节认知行为表现，但它也具有高度的灵活性且依赖于上下文，这表明工作记忆功能起到了关键作用。反过来，经颅直流电刺激前额叶皮层，已被证明能有效调节与工作记忆相关的认知表现。在一系列实验中，我们在此证明，通过阴极经颅直流电刺激降低左侧前额叶皮层的活动，能够持续且特异性地消除基于SNARC效应的隐性认知冲突，但基于视觉空间干扰的显性冲突则不受影响。这种分离是极性特异性的，并且似乎与由常规数字距离效应分类的功能数量处理无关。这些数据证明了左侧前额叶皮层在基于空间数字处理自动激活的隐性认知冲突中存在因果关系。我们的研究结果证实了脑刺激与神经认知功能之间的关键相互作用，表明通过抑制前额叶活动，可以阻断由隐性、与任务无关的信息自动激活所导致的对目标导向行为的干扰。
