Huang Jinfeng, Zhang Gaoyan, Dang Jianwu, Chen Yu, Miyamoto Shoko
Faculty of Human Sciences, University of Tsukuba, Ibaraki, Japan.
Research Institute, NeuralEcho Technology Co., Ltd., Beijing, China.
Front Hum Neurosci. 2023 Sep 1;17:1253211. doi: 10.3389/fnhum.2023.1253211. eCollection 2023.
Speech production involves neurological planning and articulatory execution. How speakers prepare for articulation is a significant aspect of speech production research. Previous studies have focused on isolated words or short phrases to explore speech planning mechanisms linked to articulatory behaviors, including investigating the eye-voice span (EVS) during text reading. However, these experimental paradigms lack real-world speech process replication. Additionally, our understanding of the neurological dimension of speech planning remains limited.
This study examines speech planning mechanisms during continuous speech production by analyzing behavioral (eye movement and speech) and neurophysiological (EEG) data within a continuous speech production task. The study specifically investigates the influence of semantic consistency on speech planning and the occurrence of "look ahead" behavior.
The outcomes reveal the pivotal role of semantic coherence in facilitating fluent speech production. Speakers access lexical representations and phonological information before initiating speech, emphasizing the significance of semantic processing in speech planning. Behaviorally, the EVS decreases progressively during continuous reading of regular sentences, with a slight increase for non-regular sentences. Moreover, eye movement pattern analysis identifies two distinct speech production modes, highlighting the importance of semantic comprehension and prediction in higher-level lexical processing. Neurologically, the dual pathway model of speech production is supported, indicating a dorsal information flow and frontal lobe involvement. The brain network linked to semantic understanding exhibits a negative correlation with semantic coherence, with significant activation during semantic incoherence and suppression in regular sentences.
The study's findings enhance comprehension of speech planning mechanisms and offer insights into the role of semantic coherence in continuous speech production. Furthermore, the research methodology establishes a valuable framework for future investigations in this domain.
言语产生涉及神经学规划和发音执行。说话者如何为发音做准备是言语产生研究的一个重要方面。以往的研究集中在孤立的单词或短短语上，以探索与发音行为相关的言语规划机制，包括在文本阅读过程中研究眼声跨度（EVS）。然而，这些实验范式缺乏对现实世界言语过程的复制。此外，我们对言语规划的神经学维度的理解仍然有限。
本研究通过分析连续言语产生任务中的行为（眼动和言语）和神经生理学（脑电图）数据，研究连续言语产生过程中的言语规划机制。该研究具体考察语义一致性对言语规划的影响以及“前瞻”行为的发生情况。
结果揭示了语义连贯在促进流畅言语产生中的关键作用。说话者在开始说话之前会获取词汇表征和语音信息，强调了语义加工在言语规划中的重要性。在行为方面，在连续阅读常规句子时，眼声跨度逐渐减小，而非常规句子的眼声跨度略有增加。此外，眼动模式分析识别出两种不同的言语产生模式，突出了语义理解和预测在高级词汇加工中的重要性。在神经学方面，言语产生的双通道模型得到支持，表明存在背侧信息流和额叶参与。与语义理解相关的脑网络与语义连贯呈负相关，在语义不连贯时显著激活，在常规句子中受到抑制。
该研究的结果增进了我们对言语规划机制的理解，并为语义连贯在连续言语产生中的作用提供了见解。此外，该研究方法为该领域未来的研究建立了一个有价值的框架。
