Table_2_Common Brain Substrates Underlying Auditory Speech Priming and Perceived Spatial Separation.DOCX

Under a “cocktail party” environment, listeners can utilize prior knowledge of the content and voice of the target speech [i.e., auditory speech priming (ASP)] and perceived spatial separation to improve recognition of the target speech among masking speech. Previous studies suggest that these two unmasking cues are not processed independently. However, it is unclear whether the unmasking effects of these two cues are supported by common neural bases. In the current study, we aimed to first confirm that ASP and perceived spatial separation contribute to the improvement of speech recognition interactively in a multitalker condition and further investigate whether there exist intersectant brain substrates underlying both unmasking effects, by introducing these two unmasking cues in a unified paradigm and using functional magnetic resonance imaging. The results showed that neural activations by the unmasking effects of ASP and perceived separation partly overlapped in brain areas: the left pars triangularis (TriIFG) and orbitalis of the inferior frontal gyrus, left inferior parietal lobule, left supramarginal gyrus, and bilateral putamen, all of which are involved in the sensorimotor integration and the speech production. The activations of the left TriIFG were correlated with behavioral improvements caused by ASP and perceived separation. Meanwhile, ASP and perceived separation also enhanced the functional connectivity between the left IFG and brain areas related to the suppression of distractive speech signals: the anterior cingulate cortex and the left middle frontal gyrus, respectively. Therefore, these findings suggest that the motor representation of speech is important for both the unmasking effects of ASP and perceived separation and highlight the critical role of the left IFG in these unmasking effects in “cocktail party” environments.在‘鸡尾酒会’场景中，听众可借助目标语音的内容与语音先验知识[即听觉语音启动（auditory speech priming, ASP）]以及感知空间分离能力，提升掩蔽语音中的目标语音识别率。既往研究表明，这两种去掩蔽线索并非独立加工。然而目前尚不明确，这两种线索的去掩蔽效应是否共享共同的神经基础。本研究旨在首先通过在统一实验范式中引入这两种去掩蔽线索，并结合功能磁共振成像技术，确认ASP与感知空间分离在多说话人环境中是否会协同提升语音识别性能，并进一步探究两种去掩蔽效应是否共享共同的脑底物。研究结果显示，ASP与感知空间分离所产生的去掩蔽效应对应的神经激活在以下脑区存在部分重叠：左侧额下回三角部（TriIFG）与眶部、左侧顶下小叶、左侧缘上回以及双侧壳核，上述脑区均参与感觉运动整合与语音产生过程。左侧三角部额下回的激活强度与ASP及感知空间分离所带来的行为绩效提升呈显著相关。与此同时，ASP与感知空间分离还分别增强了左侧额下回与两类参与抑制干扰语音信号的脑区之间的功能连接：前者对应前扣带回皮层，后者对应左侧额中回。综上，本研究结果表明，语音的运动表征对ASP与感知空间分离的去掩蔽效应均具有重要作用，并凸显了左侧额下回在‘鸡尾酒会’场景下这类去掩蔽效应中的关键作用。