Boudewyn Megan A, Carter Cameron S
Department of Psychology, University of California, 1156 High Street, Santa Cruz, CA, 95064, USA.
University of California, Irvine, CA, USA.
Cogn Affect Behav Neurosci. 2025 Aug 13. doi: 10.3758/s13415-025-01337-6.
In this study, we used transcranial direct current stimulation (tDCS), a noninvasive neuromodulation technique, to test a set of hypotheses about the extent to which the prefrontal cortex (PFC) contributes to revision and updating processes during language comprehension. Following 20 min of PFC-targeted, Active Control, or Sham tDCS, EEG was recorded while participants performed a widely used paradigm in which they read sentences containing plausible and implausible thematic roles (e.g. The actress/film-maker was directed by the film-maker/actress on set). This linguistic manipulation allowed us to examine comprehension under conditions when shallow processing and deeper processing yield conflicting meaning representations, which previous work has shown often engages revision and updating processes upon detection of the conflict. A different pattern of event-related potential responses was elicited when the same participants encountered implausible thematic roles during reading after receiving Sham compared with PFC-targeted tDCS. Specifically, N400 effects were found after Sham tDCS, whereas robust P600 effects were found after PFC-targeted tDCS (and to a significantly lesser extent, after Active Control tDCS). This suggests that while readers tended to treat implausible thematic roles as semantic anomalies after Sham tDCS, those same readers were more likely to detect conflict and engage in revision and updating in response to implausible thematic roles when in a state of heightened PFC stimulation. These results provide a novel demonstration of within-individual variability in language processing depending on current neurocognitive state and have implications for psycholinguistic theory about PFC contributions to revision and updating processes during language comprehension.
在本研究中，我们使用了经颅直流电刺激（tDCS）这一非侵入性神经调节技术，来检验一系列关于前额叶皮层（PFC）在语言理解过程中对修正和更新过程贡献程度的假设。在进行20分钟针对PFC的、主动对照或假刺激tDCS后，当参与者执行一种广泛使用的范式时记录脑电图，在该范式中他们阅读包含合理和不合理主题角色的句子（例如，女演员/电影制作人在片场被电影制作人/女演员导演）。这种语言操作使我们能够在浅层加工和深层加工产生相互冲突的意义表征的条件下检查理解情况，先前的研究表明，在检测到冲突时，这种情况通常会引发修正和更新过程。与接受针对PFC的tDCS相比，当相同的参与者在接受假刺激后阅读时遇到不合理的主题角色时，会引发不同模式的事件相关电位反应。具体而言，在假刺激tDCS后发现了N400效应，而在针对PFC的tDCS后发现了强烈的P600效应（在主动对照tDCS后程度明显较小）。这表明，虽然读者在接受假刺激tDCS后倾向于将不合理的主题角色视为语义异常，但当处于增强的PFC刺激状态时，这些读者更有可能检测到冲突并针对不合理的主题角色进行修正和更新。这些结果提供了一个关于语言加工中个体内变异性取决于当前神经认知状态的新例证，并对关于PFC在语言理解过程中对修正和更新过程贡献的心理语言学理论具有启示意义。
