Causal Evidence for a Mechanism of Semantic Integration in the Angular Gyrus as Revealed by High-Definition Transcranial Direct Current Stimulation
Causal Evidence for a Mechanism of Semantic Integration in the Angular Gyrus as Revealed by High-Definition Transcranial Direct Current Stimulation
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DOI：
10.1523/jneurosci.3120-15.2016
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发表时间：
2016-03-30
影响因子：
5.3
通讯作者：
Hamilton, Roy H.
中科院分区：
文献类型：
--
作者：
Price, Amy Rose;Peelle, Jonathan E.;Hamilton, Roy H.
人类认知的一个定义方面是将概念信息整合成复杂语义组合的能力。例如，我们可以将“格子”和“夹克”理解为单独的概念，但我们也可以毫不费力地将这些概念联合收割机组合起来形成“格子夹克”的语义表示。“许多语义记忆的神经解剖学模型提出，异模态皮层枢纽将分布式语义特征整合到连贯的表征中。然而，很少有工作专门研究这些建议的整合机制和因果关系的作用，这些地区的语义整合。在这里，我们测试的假设，角回（AG）是关键的语义信息整合应用高清晰度经颅直流电刺激（tDCS）的功能磁共振成像引导区域的兴趣在左AG。我们发现，阳极刺激左AG调制语义整合，但没有影响的字母串控制任务。具体来说，与假刺激和刺激右半球控制脑区域期间观察到的效果相比，对左AG的阳极刺激导致对语义上有意义的组合（如“小萝卜”）的理解相对于无意义的组合（如“快蓝莓”）更快。此外，大脑刺激的效果大小与单词对之间的语义连贯程度相关。这些研究结果表明，左AG在词汇语义信息的整合中起着因果作用，并且高清晰度tDCS到关联皮层中枢可以选择性地调节语义记忆中的整合过程。
A defining aspect of human cognition is the ability to integrate conceptual information into complex semantic combinations. For example, we can comprehend "plaid" and "jacket" as individual concepts, but we can also effortlessly combine these concepts to form the semantic representation of "plaid jacket." Many neuroanatomic models of semantic memory propose that heteromodal cortical hubs integrate distributed semantic features into coherent representations. However, little work has specifically examined these proposed integrative mechanisms and the causal role of these regions in semantic integration. Here, we test the hypothesis that the angular gyrus (AG) is critical for integrating semantic information by applying high-definition transcranial direct current stimulation (tDCS) to an fMRI-guided region-of-interest in the left AG. We found that anodal stimulation to the left AG modulated semantic integration but had no effect on a letter-string control task. Specifically, anodal stimulation to the left AG resulted in faster comprehension of semantically meaningful combinations like "tiny radish" relative to non-meaningful combinations, such as "fast blueberry," when compared to the effects observed during sham stimulation and stimulation to a right-hemisphere control brain region. Moreover, the size of the effect from brain stimulation correlated with the degree of semantic coherence between the word pairs. These findings demonstrate that the left AG plays a causal role in the integration of lexical-semantic information, and that high-definition tDCS to an associative cortical hub can selectively modulate integrative processes in semantic memory.