Chen Fei, Peng Gang
School of Foreign Languages, Hunan University, Changsha, China.
Research Centre for Language, Cognition, and Neuroscience, Department of Chinese and Bilingual Studies, The Hong Kong Polytechnic University, Hong Kong, China.
Front Psychol. 2020 Sep 30;11:581410. doi: 10.3389/fpsyg.2020.581410. eCollection 2020.
Previous studies have shown that for congenital amusics, long-term tone language experience cannot compensate for lexical tone processing difficulties. However, it is still unknown whether such difficulties are merely caused by domain-transferred insensitivity in lower-level acoustic processing and/or by higher-level phonological processing of linguistic pitch as well. The current P300 study links and extends previous studies by uncovering the neurophysiological mechanisms underpinning lexical tone perception difficulties in Mandarin-speaking amusics. Both the behavioral index () and P300 amplitude showed reduced within-category as well as between-category sensitivity among the Mandarin-speaking amusics regardless of the linguistic status of the signal. The results suggest that acoustic pitch processing difficulties in amusics are manifested profoundly and further persist into the higher-level phonological processing that involves the neural processing of different lexical tone categories. Our findings indicate that long-term tone language experience may not compensate for the reduced acoustic pitch processing in tone language speakers with amusia but rather may extend to the neural processing of the phonological information of lexical tones during the attentive stage. However, from both the behavioral and neural evidence, the peakedness scores of the and P300 amplitude were comparable between amusics and controls. It seems that the basic categorical perception (CP) pattern of native lexical tones is preserved in Mandarin-speaking amusics, indicating that they may have normal or near normal long-term categorical memory.
以往的研究表明，对于先天性失歌症患者而言，长期的声调语言经验无法弥补其在词汇声调处理方面的困难。然而，此类困难究竟仅仅是由较低层次听觉处理中领域转移的不敏感所致，还是也由语言音高的较高层次语音处理所导致，目前仍不明确。当前的P300研究通过揭示说普通话的失歌症患者词汇声调感知困难背后的神经生理机制，对以往研究进行了关联和拓展。无论信号的语言状态如何，行为指标（）和P300波幅均显示，说普通话的失歌症患者在类别内以及类别间的敏感性均有所降低。结果表明，失歌症患者在音高处理方面的困难表现得极为明显，并且进一步持续到涉及不同词汇声调类别的神经处理的较高层次语音处理中。我们的研究结果表明，长期的声调语言经验可能无法弥补患有失歌症的声调语言使用者降低的音高处理能力，反而可能延伸到注意力集中阶段词汇声调语音信息的神经处理过程中。然而，从行为和神经证据来看，失歌症患者与对照组在和P300波幅的峰值分数上具有可比性。说普通话的失歌症患者似乎保留了母语词汇声调的基本范畴感知（CP）模式，这表明他们可能具有正常或接近正常的长期范畴记忆。
