Non-invasive stimulation of the primary motor cortex (M1) modulates processing of decontextualized action words and sentences (i.e., verbal units denoting bodily motion). This suggests that language comprehension hinges on brain circuits mediating the bodily experiences evoked by verbal material. Yet, despite its relevance to constrain mechanistic language models, such a finding fails to reveal whether and how relevant circuits operate in the face of full-blown, everyday texts. Using a novel naturalistic discourse paradigm, we examined whether direct modulation of M1 excitability influences the appraisal of narrated actions. Following random group assignment, participants received anodal transcranial direct current stimulation over the left M1, or sham stimulation of the same area, or anodal stimulation of the left ventrolateral prefrontal cortex. Immediately afterwards, they listened to action-laden and neutral stories and answered questions on information realized by verbs (denoting action and non-action processes) and circumstances (conveying locative or temporal details). Anodal stimulation of the left M1 selectively decreased outcomes on action-relative to non-action information –a pattern that discriminated between stimulated and sham participants with 74% accuracy. This result was particular to M1 and held irrespective of the subjects’ working memory and vocabulary skills, further attesting to its specificity. Our findings suggest that offline modulation of motor-network excitability might lead to transient unavailability of putative resources needed to evoke actions in naturalistic texts, opening promising avenues for the language embodiment framework.

对初级运动皮层 (M1) 的非侵入性刺激可调节脱离语境的动作单词和句子（即表示身体运动的言语单位）的处理。这表明语言理解取决于调节言语材料引起的身体体验的大脑回路。然而，尽管它与约束机械语言模型相关，但这一发现未能揭示相关电路在面对成熟的日常文本时是否以及如何运作。使用一种新颖的自然主义话语范式，我们研究了 M1 兴奋性的直接调节是否会影响对叙述行为的评估。随机分组后，参与者在左侧 M1 上接受阳极经颅直流电刺激，或同一区域的假刺激，或左腹外侧前额叶皮层的阳极刺激。紧接着，他们聆听充满动作和中性的故事，并回答有关动词（表示动作和非动作过程）和环境（传达方位或时间细节）所实现的信息的问题。左侧 M1 的阳极刺激选择性地降低了相对于非动作信息的动作结果——这种模式能够以 74% 的准确率区分受刺激的参与者和假参与者。这一结果是 M1 特有的，并且与受试者的工作记忆和词汇技能无关，进一步证明了其特殊性。我们的研究结果表明，运动网络兴奋性的离线调节可能会导致在自然文本中唤起动作所需的假定资源暂时不可用，从而为语言体现框架开辟了有希望的途径。