心理学报, 2020, 52(1): 1-11. doi: 10.3724/SP.J.1041.2020.00001

研究报告

汉语普通话声调感知的老年化效应:来自ERP的证据

肖容, 梁丹丹,, 李善鹏

南京师范大学文学院, 南京 210097

Effects of aging on the Mandarin lexical tone perception: Evidence from ERPs

XIAO Rong, LIANG Dandan,, LI Shanpeng

School of Chinese Language and Culture, Nanjing Normal University, Nanjing 210097, China

通讯作者: 梁丹丹, E-mail: ldd233@sina.com

收稿日期: 2018-10-17   网络出版日期: 2020-01-25

基金资助: * 江苏高校优势学科建设工程资助项目(简称PAPD)资助.  

Received: 2018-10-17   Online: 2020-01-25

摘要

研究考察汉语普通话老年人前注意阶段声调感知状况, 探究是否存在领域特殊的老年化。运用事件相关电位技术, 采用被动oddball范式诱发MMN回应, 控制领域一般性因素的影响。结果显示涉及范畴变化的声调和非语音音调诱发MMN强度衰减, 不涉及范畴变化的声调诱发MMN强度未衰退。研究结果表明在前注意阶段, 在特定汉语普通话声调范畴知识加工能力上存在领域特殊的衰退, 而不涉及母语音位知识的声调的感知存在领域特殊的一定程度的保留, 这一保留与时间维度上补偿机制的调用有关。受补偿机制调节, 语言加工呈现出衰退或保留等不同的老年化进程。

关键词: 汉语普通话 ; 老年化 ; 声调 ; 前注意 ; 领域特殊

Abstract

The accurate perception of lexical tones in Mandarin Chinese is an important foundation for successfully understanding spoken Chinese. Previous behavioral studies have shown that the ability to perceive lexical tones in Mandarin declines in elderly individuals. In addition to other research areas related to language and aging, the central issue in phonetic perception during aging concerns whether perceptual changes related to aging are area-specific or area-general. The area-general language hypothesis of aging assumes that changes in language perception related to aging are caused by a decline in both general sensory perception function and high-order cognitive function. In contrast, the area-specific language hypothesis of aging assumes that changes in aging-related language perception are caused by specific deficits in language processing. Previous studies mostly detected the state of attention and focused on how area-general factors affect the processing of segmental phonemes in elderly individuals. The present study examined neurophysiological responses, particularly that of MMN, to explore whether the aging of lexical tone perception is language-specific for Mandarin.
The current study recruited 22 healthy elderly participants (age range: 55.6~79.6 years) and 18 young participants (age range: 22.7~29.0 years). In a passive oddball task, we used event-related potentials (ERPs) to examine Mandarin lexical tone perception. Three syllables from a lexical tone continuum were chosen as stimuli to form an across-category stimulus pair and a within-category stimulus pair for the ERP oddball task. A non-speech stimulus pair was generated on the basis of the within-category stimulus pair. During the experiment, participants were instructed to ignore the presented sounds while watching a self-selected movie.
ERP data showed that in the across-category condition, compared with the young group, the elderly group had a smaller MMN, and there was no between-group difference in the within-category condition. In the young group, a non-speech tone elicited a larger MMN amplitude than a speech tone that shared the same pitch contour, while the elderly group did not show a speech enhancement effect. In addition, compared with that of the young group, the amplitude of the MMN elicited by the non-speech contrast in the elderly group was significantly smaller. The results indicated that the general decline in central auditory processing function was not related to the pre-attention processing of lexical tone. In addition, when the level at which the auditory input stimulus could be sensed was controlled according to peripheral hearing abilities, the decline in peripheral auditory function was not related to the preservation of or decline in lexical tone perception in the current study.
In the current study, there is no evidence that the age-related decline in area-general factors affects tone perception in the pre-attention condition. On this basis, this study further speculated that the ability of elderly Mandarin-speaking individuals to perceive lexical tone in pre-attention conditions was preserved and only declined for specific languages, and the above-mentioned decline in the processing of knowledge of Mandarin tone category and the wider preservation of the processing of speech tones are language-specific. The present study provides evidence for the area-specific language hypothesis of aging.

Keywords: Mandarin ; aging ; lexical tone category ; pre-attention ; area-specific

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本文引用格式

肖容, 梁丹丹, 李善鹏. (2020). 汉语普通话声调感知的老年化效应:来自ERP的证据. 心理学报, 52(1), 1-11

XIAO Rong, LIANG Dandan, LI Shanpeng. (2020). Effects of aging on the Mandarin lexical tone perception: Evidence from ERPs. Acta Psychologica Sinica, 52(1), 1-11

1 前言

语言加工老年化研究聚焦于老年化是领域一般的还是特殊的这一讨论上。领域一般论认为语言加工老年化源自于一般性感知觉(例如, 听觉)和一般性认知功能(例如, 工作记忆、执行功能、注意、抑制控制等)的衰退。领域特殊论则认为老年化出现在某个特定的语言认知加工过程中, 语言功能会呈现出特殊的衰退或保留(Taylor & Burke, 2002)。具体而言, 某些语言特定功能的老年化会导致语言加工能力的衰退, 例如, 语音和语义之间连接强度的减弱会导致命名速度减缓(MacKay & Burke, 1990)。另一方面, 某些语言功能的保留也被作为领域特殊性老年化的证据, 例如, 相较于感知觉和认知功能的显著衰退, 语义知识相对得到保留(Persson et al., 2004)。

语音是语言的形式, 其加工既涉及一般性感知觉和认知能力, 也涉及语言加工特定的能力。鉴于语音的复杂性, 目前老年化研究中较多关注最小音段音位, 即单个元音或辅音音位的感知。这些研究对领域一般和特殊的问题展开了大量讨论(Bidelman, Villafuerte, Moreno, & Alain, 2014)。与此相对, 作为超音段音位的声调受到的关注则少得多。与音段音位靠音色来区别意义不同, 超音段音位的声调通过系统地控制音高来区分意义(Xi, Zhang, Shu, Zhang, & Li, 2010), 这是声调语言与日耳曼语(如, 英语)等语言的一个重要区别。汉语是典型的声调语言, 本研究将关注声调感知老年化问题。

1.1 声调感知的老年化效应:支持领域一般论的证据

声调感知包括两个层面的信息加工:从外周到中央的听觉系统对声调以频率为主的声学特征的编码和分析, 以及中枢神经系统对声调语言相关知识的调用。随着年龄增加, 听觉系统的功能方面, 外周听觉敏感度(Schneider & Pichora-Fuller, 2000)和中央听觉功能(Lister, Maxfield, Pitt, & Gonzalez, 2011)都发生衰退, 声音频率编码功能减弱。目前仅有三项研究直接考察了汉语普通话老年人的声调感知(Wang, Yang, & Liu, 2017; Wang, Yang, & Zhang, 2017; Yang et al., 2015)。这些研究均采用外显的行为识别或区分范式, 且都为领域一般论提供了证据。Wang等(2017)发现音高辨别阈值升高与声调感知能力衰退有关, 听觉功能下降会影响声调感知。Kennedy和Raz (2009)发现, 中央神经系统的结构萎缩会削弱一般性高级认知功能, 这种一般性的衰退可能会削弱声调感知, 尤其是在高级认知功能参与较多的注意状态之下。Yang等(2015)也指出注意控制等高级认知功能的下降是声调感知能力下降的原因。

1.2 声调感知领域特殊老年化的研究方法:来自音段音位感知研究的启示

目前还没有研究直接关注声调感知的领域特殊老年化问题, 但音段音位感知及其老年化的研究提供了刺激材料对比和被试实验条件下注意状态方面的启示。

1.2.1 两个层面的刺激材料对比

考察音段音位感知的领域特殊问题, 通常要包含两个层面的对比。

第一, 语音和非语音的刺激加工对比。脑电研究表明, 语音和非语音诱发的脑电回应在空间偏侧性或强度上存在差异(Shtyrov, Kujala, Palva, Ilmoniemi, & Näätänen, 2000; Sorokin, Alku, & Kujala, 2010)。大量神经影像研究也显示, 加工语音和非语音时大脑激活区域不完全相同, 存在语言特定的加工区域, 如左侧颞平面、双侧颞上沟、左侧额下回岛盖部、腹侧前运动皮质, 这些区域的激活并不只与调用特定语言的音位范畴知识有关, 当被试被动地听语音时, 对于未形成长时记忆表征的不熟悉的语音, 相比于非语音, 仍然会调用左腹部前运动皮质、颞上沟等区域(Wilson & Iacoboni, 2006), 这体现了一种广泛的、不涉及母语音系知识加工的特殊性。

老年化研究中也发现了语音感知具有不同于非语音的老年化表现(Du, Buchsbaum, Grady, & Alain, 2016; Geal-Dor, Goldstein, Kamenir, & Babkoff, 2006)。Geal-Dor等(2006)的ERP研究发现纯音比元音诱发了老年人更强的脑电回应。Du等(2016)的fMRI研究发现仅在感知辅音时, 老年人比年轻人呈现出更高的额叶言语运动区域的激活, 但感知非语音时未出现该区域激活程度的组间差异。

第二, 音系内部范畴内和范畴间变化的刺激加工对比。听话者对母语中音位的感知具有范畴化特性(categorical perception)。Liberman, Harris, Hoffman和Griffith (1957)最早发现了这一现象, 该研究利用合成器对/b/和/d/两个辅音进行处理, 生成14个共振峰连续变化的C-V音节/ba/-/da/, 听者表现出对范畴边界变化(即, 范畴间变化)的识别率高于对同一范畴内等步长刺激变化(即, 范畴内变化)的识别率, 这是范畴化感知的典型特征。这种现象源自于母语经验(Durlach & Braida, 1969), 声调语言听者感知母语声调时, 也会表现出这样的范畴化特性, 将听到的声调与记忆系统中存储的长时记忆进行比较, 从而将连续变化的声音归类于某一种声调类型(亓贝尔, 刘博, 2015)。

音段音位感知的老年化研究为范畴加工存在老年化提供了证据。行为研究发现老年化会削弱辅音音位感知的范畴化程度(Gordon-Salant & Fitzgibbons, 1993; Harkrider, Plyler, & Hedrick, 2005)。Bidelman等(2014)的脑电研究也发现, 老年人元音范畴边界相比于年轻人更模糊。

1.2.2 注意状态和前注意状态的选择

需要注意的是, 上述所有关于语音感知老年化的研究都是注意状态下的结果。目前有三个研究考察了前注意状态下, 音段音位(辅音)感知能力的老年化(Aerts, Mierlo, & Hartsuiker, 2013; Bellis, Nicol, & Kraus, 2000; Cheng, Baillet, Hsiao, & Lin, 2015), 并在解释研究结果时提及了领域特殊性视角。其中, Aerts等(2013)认为每个音位对立都以不同的、音位特定的方式发生老年化。辅音音位对立诱发的MMN (失匹配负成分)衰退的原因可能是大脑中表征辅音对立的神经元集合的连接强度降低。

与注意状态不同, 在前注意状态下, 听话者极少调用高级认知功能, 在一定程度上避免了其衰退产生的交互影响, 能够更有利于探究更内隐的语言知识是否受到老年化的影响(Aerts et al., 2013; Cheng et al., 2015)。

1.3 音位感知老年化的机制:衰退与保留

音位感知能力具有衰退或保留等不同老年化进程, 在1.2.1所述两个对比层面都有所体现:有研究发现相比于非语音, 老年人语音感知能力显著衰退(Geal-Dor et al., 2006), 也有研究报道称这一能力存在一定程度的保留(Du et al., 2016); 相比于范畴内变化, 范畴间变化感知能力显著下降(Bidelman et al., 2014), 同样也有研究显示范畴间变化探测能力保留(Bellis et al., 2000)。衰退与保留看似矛盾, 但老年化伴随神经系统的自组织过程, 保留与老年人调用补偿机制有关。

音位感知能力保留的补偿机制表现在两个方面。在空间维度上, fMRI等脑成像研究展现了更广泛区域的激活这一补偿方式(Du et al., 2016; Getzmann & Falkenstein, 2011), Du等(2016)的fMRI研究发现感知辅音时, 老年人比年轻人呈现出更高的额叶言语运动区域的激活, 且这一激活与老年人任务表现的提高相关; 在时间维度上, 前人研究认为更长的加工时间也是一种弥补感知功能衰退的补偿方式(Bellis et al., 2000), 研究发现老年人辅音变化诱发MMN回应的强度与年轻人相比没有差异, 但是其峰值潜伏期更长, 研究者指出这体现了一种时间补偿机制(Bellis et al., 2000)。

1.4 问题的提出

目前语音加工老年化研究更多关注音段音位, 但声调与其在自然属性和语言功能上都存在一些不同。因此, 声调感知的认知加工过程应该有别于音段音位, 其老年化表现也可能不同。另一方面, 目前声调感知的老年化研究仅考察了领域一般性因素的作用(Wang et al, 2017; Wang, Yang, & Zhang et al., 2017; Yang et al., 2015)。然而, 声调作为一种语言成分, 其重要性和特殊性更多地体现在语言功能上, 其感知涉及语言水平的加工(Shtyrov et al., 2000; Sorokin et al., 2010; Xi et al., 2010; Yu et al., 2017)。

基于前人研究的局限和启示, 本研究的目的为探究汉语普通话老年人前注意状态下感知声调这一超音段音位时神经水平的表现, 观察声调感知能力的衰退与保留, 据此考察是否存在领域特殊的老年化。

在方法上, 对一般性因素进行一定控制:采用被动oddball范式诱发MMN的方法。MMN是评估前注意阶段自动中央听觉差异探测的有效电生理标记, 不需要被试对刺激作有意识的判断(Näätänen, Paavilainen, Rinne, & Alho, 2007)。这一范式可将高级认知功能对感知的影响尽可能降低。此外, 本研究将根据老年人听觉阈值衰退程度调整呈现刺激的感觉水平, 以控制外周听觉功能下降产生的影响(参考Ross, Fujioka, Tremblay, & Picton, 2007)。

除了上述因素外, 中央听觉功能下降也是影响声调感知的一种一般性衰退, 而MMN既能反映中央听觉系统对刺激声学差异的探测, 也能反映中央皮质对刺激语言特征差异的探测(Näätänen et al., 2007)。所谓特殊, 是在与“一般”的对照中显现出来的。为分离开语言功能和一般性中央听觉功能衰退的影响, 以及语言加工老年化的两个层面, 引入非语音音调、范畴间变化声调、范畴内变化的声调等对照组, 比较不同类型刺激诱发的MMN回应。

2 方法

2.1 被试

选取年轻组被试18人(平均年龄24.2岁, 年龄范围22.7~29.0岁, 男性9人, 女性9人)和老年组被试22人(平均年龄66.2岁, 年龄范围55.6~79.6岁, 男性11人, 女性11人)。所有被试满足以下条件:母语为汉语、普通话标准; 没有言语或语言发展障碍; 经Edinburg Handedness Inventory (Oldfield, 1971)测定为右利手; 达到大学本科或专科学历; 视力或矫正视力正常; 音乐训练史少于3年; 没有神经或精神障碍史; 实验期间未服用会影响神经系统的药物。除了上述条件之外, 老年人在Mini- Mental State Examination (M. F. Folstein, S. E. Folstein, & McHugh, 1975)上的得分≥27, 被测定为无老年痴呆症。

2.2 听力测试

使用听觉实验仪测试被试的125~8000 Hz双耳七度间隔空气传导纯音阈值, 以此衡量被试外周听力。所有被试纯音平均值512~4000 Hz ≤ 45 dB HL, 6000~8000 Hz ≤ 70 dB HL, 双耳之间不存在不对称(最多只在一个频率上的阈值差大于15 dB HL), 即不存在传导性听觉损伤。

2.3 脑电实验

2.3.1 刺激

脑电实验中的刺激包括两对语音刺激(范畴间对比、范畴内对比)和一对非语音刺激。首先通过经典声调范畴感知测试确定范畴间对比和范畴内对比刺激。选择汉语普通话中最易区分的第二声和第四声作为范畴感知的测试项。由于汉语音节对应语素, 有承载意义的功能, 有研究表明语义变化也会诱发MMN (Shtyrov & Pulvermuller, 2002), 为排除语义因素干扰, 所选音节均为假音节。我们列举了汉语普通话中所有第二声和第四声都是假音节的音节对, 请15名汉语者为其语义联想度打分, 提醒打分者语义联想也可以来自于方言和外语, 选出平均语义联想度最低的15对音节; 之后请一位汉语普通话母语者录制这些音节对的发音, 采样率为44.l kHz。

在非语音刺激生成方面, 考虑到研究目的是探究是否存在语音特定的衰退, 需控制语音和非语音刺激的物理特征。有研究发现频谱复杂度较低的纯音比谐波丰富的复合音诱发的MMN振幅显著更小(Takegata, Tervaniemi, Alku, Ylinen, & Näätänen, 2008)。因此为排除频谱复杂度的影响, 本研究采用旋转语音频谱的方式生成非语音。使用一个由Scott, Blank, Rosen和Wise (2000)发布的MATLAB (版本:R2011a, Mathworks)脚本处理刺激(见http:// www.phon.ucl.ac.uk/resource/software.php), 使原始刺激的高频转变成低频, 低频转变成高频。但前人研究发现擦音、鼻音和塞音等辅音旋转前后相似(Blesser, 1972), 听感上仍像语音。为确保语音旋转后的声音听感上确为非语音, 请15位汉语者为语音对旋转后的非语音的语音相似度(即和人类发出的语音相似的程度)打分。结果显示平均语音相似度最低的为/we2/和/we4/旋转后的非语音对。最终将/we2/和/we4/作为实验刺激。

在原始录音材料的基础上生成声调连续统(声调连续统是指一组基频频率呈现连续变化的合成声信号)。前人研究一致表明, 音高曲线在汉语普通话声调感知中起主要作用(林茂灿, 颜景助, 孙国华, 1984)。因此本研究通过改变音节的音高曲线以改变其声调。使用Praat软件调整音节声学参数, 为了控制/we2/和/we4/两个音节除了音高曲线之外的声音起始时间、平均强度、时长、音高、包络等其他声学特征都相同, 通过将/we2/的音高曲线去除, 留下其他频谱成分, 将/we4/的音高曲线复制到/we2/的频谱上的方法生成两个刺激, 刺激时长为250 ms, 包括10 ms升降时间, 音量为70 dB。

将上述两个刺激作为声调连续统的两端, 采用PSOLA合成技术生成15个刺激, 作为声调范畴感知的测试材料, 刺激的音高曲线如图1所示。要求被试坐在屏幕前, 认真阅读指导语后按任意键开始实验。正式实验前进行预实验, 预实验共有10个trail, 要求被试判断电脑扬声器播放出来的声音是第二声还是第四声, 按键作出反应。每个刺激随机孤立呈现20次。测试时长约10分钟。分别统计年轻组和老年组在连续统的每个声调上识别成四声的比率, 生成两组的范畴感知曲线, 如图2所示。

图1

图1   从/we2/到/we4/的音高曲线连续统。


图2

图2   年轻组和老年组的范畴感知曲线


图2所示, T5和T10是两组被试声调范畴感知的拐点, T5及T5之前的声调大概率被识别为第二声, T10及T10之后的声调大概率被识别为第四声。脑电实验中范畴间声调对比block的标准刺激为T10, 偏差刺激为T5, 二者既有音高曲线也有声调范畴的差异。范畴间和范畴内对比的标准刺激和偏差刺激的声学差异程度相同。范畴内声调对比block的标准刺激为T10, 偏差刺激为T15, 二者只有音高曲线的差异。脑电实验开始前, 再次请所有被试依次判断三个声调分别是四声中的第几声。结果显示, 所有参与被试都将T5和T10识别为不同声调范畴, 将T10和T15识别为相同声调范畴, 这表明T10和T5之间是范畴间变化, T10和T15之间则是范畴内变化。

用Praat软件将语音刺激的音高曲线删除后, 采用上述频谱旋转的方式, 生成不带声调的非语音刺激, 再用Praat软件分别将T10和T15的音高曲线复制到非语音刺激的频谱上, 形成非语音音调对比block中的标准刺激和偏差刺激, 这样使得这一条件下的偏差刺激和标准刺激之间音高曲线的差异与范畴内声调对比block完全相同。

2.3.2 实验过程

脑电实验均采用经典听觉被动oddball范式。标准刺激出现的概率为90%, 偏差刺激为10%。共有三个程序相同的block:范畴间声调对比block、范畴内声调对比block、非语音音调对比block。每个block中有1015个trial, 每个block开始的15个刺激为标准刺激。偏差刺激以伪随机的顺序呈现, 2个偏差刺激之间至少有2个标准刺激。刺激呈现时间间隔为650 ms。3个block随机呈现, 每个block持续时间为15分钟, 每两个block之间有5分钟休息时间。

要求被试观看自选无声视频, 并忽视耳机里的声音。播放视频的电脑距离被试70 cm。刺激通过耳机双耳呈现, 为所有年轻被试呈现的音量为70 dB, 根据老年人的空气传导听力阈值设置其声音呈现的强度。若年轻人的平均听力阈值为X, 老年人的听力阈限比X每高出5 dB, 则强度增加5 dB, 以控制刺激对于两个被试组的感觉水平(SL), 从而排除ERP效应简单地反映听力差异的可能性。

2.3.3 脑电记录

实验仪器为Brain Products, SynAmps2型放大器。采用32导电极帽, 以左、右侧乳突为参考连续记录脑电。AC采样, 采样频率为500 Hz/导, 头皮电阻均小于5 kΩ。

2.3.4 ERP数据分析

离线处理时采用Brain Vision Analyzer 2.1脑电数据处理软件。取刺激前100 ms到刺激后500 ms的600 ms为分析时程(epoch)。自动矫正眨眼等伪迹, 波幅大于± 100 μV的脑电事件视为伪迹自动剔除。离线滤波的频带宽度为1~50 Hz。最后对各个实验条件下诱发的脑电信号分别进行叠加。

3 结果

每组各有两名被试因EEG信号伪迹太多被剔除, 最终老年组和年轻组分别分析了20名和16名被试的数据。老年组和年轻组在加工音调时, Fz电极点上各种条件下产生脑电回应如图3所示。

图3

图3   范畴间声调、范畴内声调、非语音音调三种条件下老年组和年轻组两组被试产生的MMN。(A) Fz电极点上三种条件下两组被试的MMN总平均波形。(B) MMN分析时间窗内平均振幅的电压地形图。


Fz电极点诱发MMN的总平均波幅在刺激呈现后226 ms达到峰值, 从波峰向两边各取30 ms, 即刺激呈现后196~256 ms作为分析时间窗。

首先, 进行MMN可靠性检验。对两组被试分别进行以变体刺激在F3、Fz、F4、C3、Cz、C4、P3、Pz、P4电极点诱发的MMN波幅与零水平的单样本t检验, 结果显示:在三种条件下, 年轻组所有电极点都诱发出可靠的MMN, ps < 0.05; 老年组除了在非语音音调对比条件下P3、Pz、P4没有诱发出可靠的MMN, ps > 0.05, 范畴内声调对比条件下P4的MMN波幅边缘显著大于零, p = 0.062, 其他电极点都诱发出了可靠的MMN, ps < 0.05。

以音调类型和组别为自变量, 变体刺激诱发MMN的峰值潜伏期和平均振幅为因变量分别做3(音调类型:范畴间声调/范畴内声调/非语音音调)×2(组别:老年组/年轻组)的两因素重复测量方差分析。结果如表1所示。

表1   以音调类型、组别为自变量, 峰值潜伏期、平均振幅为因变量的方差分析的结果

自变量 潜伏期 平均振幅
F η2p F η2p
音调类型(1, 34) 3.238 0.164 2.715 0.141
组别(1, 34) 14.201** 0.295 4.973* 0.128
组别×音调类型(1, 34) 3.346* 0.169 8.224** 0.333

注:** p < 0.01, * p ≤ 0.05, † 0.05 < p < 0.07, 其余p ≥ 0.07。

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对显著的交互作用分别做简单效应分析, 结果显示:

在潜伏期上, 相比于年轻组, 老年组范畴间声调诱发MMN峰值潜伏期显著更长, p < 0.001, 范畴内声调也显著更长, p = 0.027, 而非语音音调两组没有显著差异, p = 0.780, 如图4所示。

图4

图4   老年组和年轻组三种类型音调诱发MMN峰值潜伏期


在振幅上, 相比于年轻组, 老年组范畴间声调明显减小, p = 0.02, 非语音音调也显著减小, p = 0.002, 但是范畴内声调上两组没有显著差异, p = 0.448。如图5所示。

图5

图5   老年组和年轻组三种类型音调诱发MMN平均振幅


最后, 对老年组和年轻组在三种声调对比条件下MMN的平均振幅做2(偏侧性:左/右) × 3(位置:额部/顶部/颞部) × 2(组别:年轻组/老年组)的三因素重复测量方差分析。选取F3、F4、C3、C4、P3、P4作为分析电极, 分析时间窗为196~256 ms, 即与振幅最大的Fz的时间窗相同(参考Ren, Tang, Li, & Sui, 2013)。结果如表2所示。

表2   以三种音调类型的位置、偏侧性、组别为自变量, 平均振幅为因变量的方差分析的结果

变异来源 范畴间 范畴内 非语音
F η2p F η2p F η2p
位置(2, 68) 8.446** 0.199 9.394** 0.216 15.866** 0.318
组别(1, 34) 5.625* 0.142 0.037 0.001 22.073** 0.394
偏侧性(1, 34) 1.540 0.043 0.688 0.020 0.626 0.018
偏侧性×位置(2, 68) 0.120 0.004 1.051 0.030 3.864* 0.102
偏侧性×组别(1, 34) 2.836 0.077 0.516 0.015 0.095 0.003
组别×位置(2, 68) 2.547 0.007 0.792 0.023 0.84 0.024
偏侧性×位置×组别(2, 68) 2.549 0.070 0.020 0.001 1.886 0.053

注:** p < 0.01, * p ≤ 0.05, † 0.05 < p < 0.07, 其余p ≥ 0.07

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上述方差分析结果显示, 仅在范畴间和非语音两种对比条件下组别主效应显著, 老年组MMN平均振幅都显著小于年轻组。三种条件下位置主效应都显著, 对其分别进行事后多重比较, 结果显示:在三种音调类型下, 额部和顶部都显著大于颞部, ps < 0.01, 额部和顶部差异不显著, p > 0.05。

非语音条件下, 偏侧性和位置的交互作用显著。简单效应分析结果显示:在左侧, 额部和顶部都显著大于颞部, ps < 0.01, 额部和顶部差异不显著, p = 0.34; 在右侧, 三个区域两两之间差异都显著, 振幅由大到小为:额部>顶部>颞部, ps < 0.05。

由于老年组的年龄跨度较大, 组内可能存在较大的异质性, 因此最后对老年组内做了补充分析, 检验方法和前述有关平均振幅、潜伏期和空间分布的分析仅有两处不同:(1)添加协变量——年龄; (2)仅针对老年组。结果显示, 有关空间分布的检验中, 在范畴间对比条件下, 年龄和偏侧性交互作用显著, p = 0.013, η2 = 0.295, 随着年龄的增长, 由左偏侧转向右偏侧。其余分析结果均未显示出显著的年龄主效应或年龄与其他因素的交互作用, ps > 0.05。

4 讨论

本研究旨在探究汉语普通话老年人前注意阶段声调感知状况, 重点考察领域特殊性因素在语言加工老年化中的作用。研究结果显示:在范畴间条件下, 和年轻组相比, 老年组MMN峰值潜伏期和平均振幅都呈现出一致的、明显的衰退(即, 平均振幅减小, 峰值潜伏期延长); 在非语音条件下, 仅平均振幅有明显的衰退; 在范畴内条件下, 仅峰值潜伏期有明显的衰退。一般认为MMN的振幅相较于潜伏期更可靠(赵仑, 2010), 本研究结论的得出也以MMN平均振幅作为因变量进行统计分析的结果为主, 以MMN的峰值潜伏期作为因变量的结果为辅。本研究表明:即使是在认知要求较低的前注意阶段, 汉语普通话老年人对涉及范畴变化的母语声调的感知仍然会呈现出一定程度的老年化。更广泛的不涉及母语音位知识的声调的感知能力相对保留, 这与中央听觉系统对音调变化探测的一般性衰退形成对比, 这一保留可能源自于时间维度上补偿机制的调用。从研究意义上看, 本研究为语言加工老年化领域争论的核心问题提供了来自汉语普通话的新证据, 同时发现了超音段音位感知老年化的神经水平的线索。

4.1 语音与非语音对比层面存在领域特殊的保留

该对比层面观察的是范畴内声调和非语音音调诱发的MMN回应, 这两类刺激音调的物理变化完全相同, 且都不涉及具体音系知识的变化, 因而可以探究在广泛的语音和非语音对比层面, 是否存在领域特殊的老年化。研究结果显示相比于年轻组, 非语音音调对比诱发的老年组的MMN平均振幅更小, 而两组在范畴内声调区分上没有显示出MMN激活强度的差异; 年轻组组内, 相比于范畴内声调对比, 非语音音调对比诱发了更大的MMN平均振幅, 而老年组没有显示出非语音的回应增强效应。Geal-Dor等(2006)也综合考察了老年人对非语音、元音等多种声音信号的脑电回应, 发现老年人对语音信号的回应强度不同于非语音信号, 由此认为语音感知老年化具有领域特殊性。但这一研究中非语音刺激的频谱结构远比语音简单, 两类刺激诱发脑电回应差异可能源自于初级声音的物理信号分析能力的衰退。本研究通过旋转语音频谱的方式生成非语音, 从而控制了语音和非语音的频谱复杂度, 因此被试早期对两者声音物理特征的加工相似(Christmann, Berti, Steinbrink, & Lachmann, 2014)。但是从上述结果上看, 老年组在非语音和语音音调上仍然呈现出了不同的老年化表现:非语音音调的区分上存在明显的衰退, 但不涉及音位范畴知识加工的语音音调区分上存在领域特殊的保留。有研究显示相比于一般性感知觉和高级认知功能, 老年人的语言功能相对得到保留(Persson et al., 2004), 研究也认为这些模块特定的保留可以为语言加工老年化的领域特殊论提供支持。

综上所述, 普通话母语者对于那些不涉及母语音位知识的语音音调感知具有不同于非语音的老年化表现, 后者反映的是对音调的一般性中央听觉加工的老年化。这表明, 语音音调的感知老年化存在领域特殊性, 具体表现为:虽然音调的一般性中央听觉加工发生显著的老年化, 但是在语音音调感知上存在一定程度的保留。

4.2 范畴间与范畴内对比层面存在领域特殊的衰退

该对比层面观察的是范畴间和范畴内声调诱发的MMN回应, 这两类刺激音调的声学变化程度相同, 但只有前者涉及范畴的变化, 因而可以探究在范畴知识的调用上是否存在老年化。研究结果显示, 老年组对范畴间声调对比的回应强度显著小于年轻组, 而在范畴内声调对比条件下, 两组没有显著差异; 两组组内, 相比于范畴内声调对比, 范畴间声调对比诱发了年轻组平均振幅更大的MMN回应, 而老年组没有显示出这一范畴变化的回应增强效应。上述结果表明汉语普通话老年人前注意状态下不能感知声调范畴信息, 与之相反, 年轻人加工涉及到母语中音位对立的言语信号时, 能够自动提取其范畴信息, 而对范畴内语音差异显示出降低的敏感度, 结果表明, 在前注意阶段声调范畴信息的调用上存在衰退。

目前为止仅有的考察前注意阶段音位感知的老年化问题的三个研究得出了不一致的结论(Aerts et al., 2013; Bellis et al., 2000; Cheng et al., 2015)。早期研究显示老年组和年轻组辅音对比诱发的MMN的振幅、潜伏期都不存在显著差异, 认为老年人不存在音位前注意区分上的衰退(Bellis et al., 2000)。与本研究采用额部的Fz作为分析电极不同的是, Bellis等(2000)采用颞部的电极作为分析电极。前人研究结果显示, 相比于颞部电极, 额部电极诱发了更可靠的MMN (Xi et al., 2010)。另外, 本研究老年被试平均年龄为66.2岁, 而Bellis等(2000)研究的被试年龄仅为55周岁左右, 这个年龄的被试关于音位变化的神经表征可能还未出现显著的衰退。本研究结果与Aerts等(2013)相近, 这一研究显示老年组范畴间辅音对比诱发Fz和Cz的MMN潜伏期显著增长, 平均振幅显著减小。Cheng等(2015)采用MEG技术, 结果也显示老年组MMNm潜伏期增长, 激活强度减小, 上述两个研究都认为老年人存在音位前注意区分上的衰退。上述三个研究中所有的辅音对比都涉及范畴变化, 即本研究中的范畴间对比, 这些结果暗示老年人前注意阶段音位范畴信息的调用存在与年龄相关的衰退。

然而, 上述研究只设置了范畴间即音位水平的刺激, 这意味着变体刺激和标准刺激之间不仅有声学特征的变化, 也有音位范畴的变化, 因而所得到的年龄效应可能与一般性听觉功能的衰退有关。本研究则通过范畴内和范畴间声调对比诱发MMN的差异进一步证明了老年人在范畴加工上存在特殊的衰退。有研究认为在前注意阶段, 不同语音单位的区分与不同长时语音记忆痕迹的激活有关(Näätänen et al., 1997)。这些痕迹基于语音对比的识别模式, 随着语言发展逐渐成熟, 且对于一个人的母语而言具有特定性(Shtyrov et al., 2000)。声调范畴的长时记忆痕迹可能发生着和年龄相关的变化, 记忆痕迹内部连接强度减弱(Aerts et al., 2013), 进而导致声调范畴区分能力发生衰退。

4.3 领域特殊的保留与补偿机制的调用有关

如前文所述, 本研究发现老年人对范畴内声调的区分能力存在领域特殊的保留。根据前人研究, 加工时长的增加可以从时间维度上反映老年化进程中补偿机制的调用(Bellis et al., 2000)。本研究中三种条件下两组被试峰值潜伏期的表现如下:非语音条件下, 两组MMN峰值潜伏期没有显著差异; 范畴内声调条件下, 老年组的MMN峰值潜伏期显著长于年轻组; 范畴间对比条件下, 老年组也显示出明显的峰值潜伏期的延长。根据以上峰值潜伏期表现, 结合两组被试MMN的回应强度对比, 本研究推测, 老年人在非语音条件下, 没有调用补偿机制; 补偿只发生在语音层面, 但补偿的效果有差别, 范畴间条件下补偿不够用, 范畴内补偿成功。

这种差异反映了语言内部老年化进程的不同, 可能老年化一开始是用补偿抵消衰退, 从而呈现出保留的状况, 但在一些问题上补偿机制的调用不足以弥补更大程度的与年龄相关的衰退。在本研究中, 相比于广泛的不含音位范畴变化的语音, 老年人在涉及范畴变化的语音的知觉上存在更大程度的衰退, 虽然峰值潜伏期延长, 但未能补偿到足够高的水平, 导致其呈现出明显的衰退。

空间维度上, 前人研究发现在进行语言加工时, 神经招募空间的特定性随着年龄的增长而降低, 老年人招募空间范围扩大, 有研究将这一特定性的降低也解释为一种补偿机制(Dennis & Cabeza, 2008)。然而, 本研究关于空间分布的检验结果显示, 所有三种音调变化条件下的MMN平均振幅都未显示出任何显著的组别与偏侧性(左/右), 组别与位置(额部/顶部/颞部), 或者组别、偏侧性和位置的交互作用。这表明, MMN回应强度未呈现出空间分布上的与年龄相关的变化。在三种条件下, 无论是老年组还是年轻组, 额部和顶部MMN强度都无显著差异, 且都明显大于颞部。这与前人关于辅音前注意感知老年化的研究结果相一致(Aerts et al., 2013)。前人研究一致显示MMN回应主要分布于额部与中央(Näätänen et al, 1997; Xi et al., 2010)。同时, 在三种条件下, 无论是老年组还是年轻组, MMN回应强度都未呈现出任何半球偏侧化效应。Cheng等(2015)采用了空间分辨率更高的脑磁图技术, 研究结果也显示辅音对比诱发失匹配回应的偏侧化模式未发生与年龄相关的变化。本研究和前人研究结果表明年龄的增长并不会引起各种神经回应都呈现出空间分布特定性的降低, 如本研究关注的MMN回应则呈现出较稳定的、不易受年龄和刺激类型影响的额部和中央, 以及双侧分布的空间特征。综上所述, 在空间维度上, 不存在MMN回应的补偿机制。

本研究的一个不足之处是招募的老年被试年龄范围较广(55.6~79.6岁), 组内异质性大。为探究年龄因素的作用, 将年龄作为协变量, 对老年组内进行进一步分析的结果显示, 仅在范畴间对比条件下出现了显著的年龄和偏侧性的交互作用, 随着年龄的增长, 由左偏侧转向右偏侧化。其余分析结果均未显示出显著的年龄主效应或年龄与其他因素的交互作用。这表明, 老年人加工涉及母语音位范畴知识的声调时, 年龄会导致分布优势半球的转变。年龄的增长会对声调感知的神经机制产生一定程度的直接影响。需要注意的是, 年轻组(22.7~29.0岁)在同样的条件下未出现偏侧性效应, 即双侧对称激活。生命历程中, 可能还经历了偏侧性的出现等变化。未来可将老年组内部继续划分出更多的年龄段, 并增加中年组, 进一步考察声调感知老年化的轨迹。

5 结论

汉语普通话老年人前注意阶段声调感知存在语言领域特殊的衰退和保留:在特定汉语普通话声调范畴知识加工能力上存在领域特殊的衰退, 而在更广泛的语音音调加工能力上存在领域特殊的保留, 保留和衰退反映了受补偿机制调节的, 老年化的不同阶段, 本研究表明语言加工老年化具有领域特殊性。

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Objective: The objective of this study was to describe the auditory evoked response to silent gaps for a group of older adults using stimulus conditions identical to those used in psychophysical studies of gap detection. Design: The P1-N1-P2 response to the onsets of stimuli (markers) defining a silent gap for within-channel (spectrally identical markers) and across-channel (spectrally different markers) conditions was examined using four perceptually-equated gap durations. Study Sample: A group of 24 older adults (mean age = 63 years) with normal hearing or minimal hearing loss participated. Results: Older adults exhibited neural activation patterns that were qualitatively different and more frontally oriented than those observed in a previous study (Lister et al., 2007) of younger listeners. Older adults showed longer P2 latencies and larger P1 amplitudes than younger adults, suggesting relatively slower neural travel time and altered auditory inhibition/arousal by irrelevant stimuli. Conclusion: Older adults appeared to recruit later-occurring T-complex-like generators for gap processing, compared to earlier-occurring T-complex-like generators by the younger group. Early and continued processing of channel cues with later processing of gap cues may represent the inefficiency of the aging auditory system and may contribute to poor speech understanding in noisy, real-world listening environments.

MacKay >D. G., & Burke D. M . ( 1990).

Chapter five cognition and aging: a theory of new learning and the use of old connections

In Advances in Psychology (Vol. 71, pp. 213-263). North-Holland.

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Näätänen R., Lehtokoski A., Lennes M., Cheour M., Huotilainen M., Iivonen A., … Alho K . ( 1997).

Language-specific phoneme representations revealed by electric and magnetic brain responses

Nature, 385, 432-434.

URL     PMID:9009189      [本文引用: 2]

There is considerable debate about whether the early processing of sounds depends on whether they form part of speech. Proponents of such speech specificity postulate the existence of language-dependent memory traces, which are activated in the processing of speech but not when equally complex, acoustic non-speech stimuli are processed. Here we report the existence of these traces in the human brain. We presented to Finnish subjects the Finnish phoneme prototype /e/ as the frequent stimulus, and other Finnish phoneme prototypes or a non-prototype (the Estonian prototype /õ/) as the infrequent stimulus. We found that the brain's automatic change-detection response, reflected electrically as the mismatch negativity (MMN), was enhanced when the infrequent, deviant stimulus was a prototype (the Finnish /ö/) relative to when it was a non-prototype (the Estonian /õ/). These phonemic traces, revealed by MMN, are language-specific, as /õ/ caused enhancement of MMN in Estonians. Whole-head magnetic recordings located the source of this native-language, phoneme-related response enhancement, and thus the language-specific memory traces, in the auditory cortex of the left hemisphere.

Näätänen R., Paavilainen P., Rinne T., & Alho K . ( 2007).

The mismatch negativity (MMN) in basic research of central auditory processing: a review

Clinical Neurophysiology, 118( 12), 2544-2590.

URL     PMID:17931964      [本文引用: 2]

In the present article, the basic research using the mismatch negativity (MMN) and analogous results obtained by using the magnetoencephalography (MEG) and other brain-imaging technologies is reviewed. This response is elicited by any discriminable change in auditory stimulation but recent studies extended the notion of the MMN even to higher-order cognitive processes such as those involving grammar and semantic meaning. Moreover, MMN data also show the presence of automatic intelligent processes such as stimulus anticipation at the level of auditory cortex. In addition, the MMN enables one to establish the brain processes underlying the initiation of attention switch to, conscious perception of, sound change in an unattended stimulus stream.

Oldfield R. C . ( 1971).

The assessment and analysis of handedness: the Edinburgh inventory

Neuropsychologia, 9( 1), 97-113.

URL     PMID:5146491      [本文引用: 1]

Persson J., Sylvester C. Y. C., Nelson J. K., Welsh K. M., Jonides J., & Reuter-Lorenz P. A . ( 2004).

Selection requirements during verb generation: differential recruitment in older and younger adults

Neuroimage, 23( 4), 1382-1390.

URL     [本文引用: 2]

Age-related differences in cognitive performance are well documented. These differences are most pronounced during tasks with high demands on cognitive control, and it has been proposed that selective alteration of prefrontal activity is associated with cognitive changes in old age. Here, differences in the neural systems underlying selection requirements for older and younger adults were investigated using functional magnetic resonance imaging (fMRI). A verb generation task was used, and selection requirements were varied with regard to whether each noun could be associated with either few (scissors&mdash;cut) or many (ball&mdash;bounce, kick, throw&hellip;) competing alternatives. The two age groups showed statistically equivalent behavioral performance across the task conditions but marked differences in activation. Across both age groups, high selection demands activated several regions including bilateral frontal, left anterior frontal, left inferior temporal regions, and the dorsal anterior cingulate cortex (ACC). Between-group comparisons using region-of-interest analyses revealed less activation for senior adults in left inferior frontal gyrus (IFG), left inferior temporal gyrus, and the anterior cingulate and higher activation in right inferior frontal gyrus compared to young adults. These findings indicate age-related changes in multiple regions contributing to aspects of selection requirements during verb generation.

, Qi B. E., & Liu B . ( 2015).

The review of categorization features of tone perception

Journal of Clinical Otorhinolaryngology Head and Neck Surgery, 29( 15), 1396-1400.

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[ 亓贝尔, 刘博 . ( 2015).

声调知觉的范畴化特征及其研究进展

临床耳鼻咽喉头颈外科杂志, 29( 15), 1396-1400.]

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Ren G. Q., Tang Y. Y., Li X. Q., & Sui X . ( 2013).

Pre-attentive processing of Mandarin tone and intonation: Evidence from event-related potentials

In Functional brain mapping and the endeavor to understand the working brain. IntechOpen.

URL     PMID:27568075      [本文引用: 1]

Event-related potentials (ERPs) were used to investigate the online processing of tone and intonation in Mandarin at the attentive stage. We examined the behavioral and electrophysiological responses of native Mandarin listeners to Mandarin sentences, which contrast in final tones (rising Tone2 or falling Tone4) and intonations (Question or Statement). A clear P300 effect was observed for question-statement contrast in sentences ending with Tone4, but no ERP effect was found for question-statement contrast in sentences ending with Tone2. Our results provide ERP evidence for the interaction of tone and intonation in Mandarin, confirming the findings with behavioral metalinguistic data that native Mandarin listeners can distinguish between question intonation and statement intonation when the intonation is associated with a final Tone4, but fail to do so when the intonation is associated with a final Tone2. Our study extended the understanding of online processing of tone and intonation (1) from the pre-attentive stage to the attentive stage and (2) within a larger domain (i.e. multi-word utterances) than a single word utterance.

Ross B., Fujioka T., Tremblay K. L., & Picton T. W . ( 2007).

Aging in binaural hearing begins in mid-life: evidence from cortical auditory-evoked responses to changes in interaural phase

Journal of Neuroscience, 27( 42), 11172-11178.

URL     PMID:17942712      [本文引用: 1]

Older adults often have difficulty understanding speech in a noisy environment or with multiple speakers. In such situations, binaural hearing improves the signal-to-noise ratio. How does this binaural advantage change with increasing age? Using magnetoencephalography, we recorded cortical activity evoked by changes in interaural phase differences of amplitude-modulated tones. These responses occurred for frequencies up to 1225 Hz in young subjects but only up to 940 Hz in middle-aged and 760 Hz in older adults. Behavioral thresholds also decreased with increasing age but were more variable, likely because some older adults make effective use of compensatory mechanisms. The reduced frequency range for binaural hearing became significant in middle age, before decline in hearing sensation and the morphology of cortical responses, which became apparent only in the older subjects. This study provides evidence from human physiological data for the early onset of biological aging in binaural hearing.

, Schneider B. A., & Pichora-Fuller M. K . ( 2000).

Implications of perceptual deterioration for cognitive aging research

In F. I.M. Craik & T. A. Salthouse (Eds.), Handbook of aging and cognition(2nd ed., pp. 155-220). Mahwah, NJ: Erlbaum.

[本文引用: 1]

Scott S. K., Blank C. C., Rosen S., & Wise R. J . ( 2000).

Identification of a pathway for intelligible speech in the left temporal lobe

Brain, 123( 12), 2400-2406.

URL     PMID:11099443      [本文引用: 1]

It has been proposed that the identification of sounds, including species-specific vocalizations, by primates depends on anterior projections from the primary auditory cortex, an auditory pathway analogous to the ventral route proposed for the visual identification of objects. We have identified a similar route in the human for understanding intelligible speech. Using PET imaging to identify separable neural subsystems within the human auditory cortex, we used a variety of speech and speech-like stimuli with equivalent acoustic complexity but varying intelligibility. We have demonstrated that the left superior temporal sulcus responds to the presence of phonetic information, but its anterior part only responds if the stimulus is also intelligible. This novel observation demonstrates a left anterior temporal pathway for speech comprehension.

Shtyrov Y., & Pulvermüller F . ( 2002).

Neurophysiological evidence of memory traces for words in the human brain

Neuroreport, 13( 4), 521-525.

URL     PMID:11930174      [本文引用: 1]

Mismatch negativity (MMN), an index of experience-dependent memory traces, was used to investigate the processing of lexical contrasts in the human brain. The MMN was elicited either by rare words presented among repetitive words or pseudowords, or by pseudowords presented among words. Phonetic and phonological contrasts were identical in all conditions. MMNs elicited by both word deviants were larger than that elicited by the deviant pseudoword. The presence of lexical contrast did not significantly alter the word-elicited MMNs, which were, however, distinct in amplitude and topography from the MMN evoked by pseudowords. Thus, our results indicate the existence of word-related MMN enhancement largely independent of the lexical status of the standard stimulus. This enhancement may reflect the presence of a long-term memory trace for a spoken word.

Shtyrov Y., Kujala T., Palva S., Ilmoniemi R. J., & Näätänen R . ( 2000).

Discrimination of speech and of complex nonspeech sounds of different temporal structure in the left and right cerebral hemispheres

Neuroimage, 12( 6), 657-663.

URL     PMID:11112397      [本文引用: 3]

The key question in understanding the nature of speech perception is whether the human brain has unique speech-specific mechanisms or treats all sounds equally. We assessed possible differences between the processing of speech and complex nonspeech sounds in the two cerebral hemispheres by measuring the magnetic equivalent of the mismatch negativity, the brain's automatic change-detection response, which was elicited by speech sounds and by similarly complex nonspeech sounds with either fast or slow acoustic transitions. Our results suggest that the right hemisphere is predominant in the perception of slow acoustic transitions, whereas neither hemisphere clearly dominates the discrimination of nonspeech sounds with fast acoustic transitions. In contrast, the perception of speech stimuli with similarly rapid acoustic transitions was dominated by the left hemisphere, which may be explained by the presence of acoustic templates (long-term memory traces) for speech sounds formed in this hemisphere.

Sorokin A., Alku P., & Kujala T . ( 2010).

Change and novelty detection in speech and non-speech sound streams

Brain research, 1327, 77-90.

URL     PMID:20188710      [本文引用: 2]

The aim of the present study was to determine differences in cortical processing of consonant-vowel syllables and acoustically matched non-speech sounds, as well as novel human and nonhuman sounds. Event-related potentials (ERPs) were recorded to vowel, vowel duration, consonant, syllable intensity, and frequency changes as well as corresponding changes in their non-speech counterparts with the multi-feature mismatch negativity (MMN) paradigm. Enhanced responses to linguistically relevant deviants were expected. Indeed, the vowel and frequency deviants elicited significantly larger MMNs in the speech than non-speech condition. Minimum-norm source localization algorithm was applied to determine hemispheric asymmetry in the responses. Language relevant deviants (vowel, duration and - to a lesser degree - frequency) showed higher activation in the left than right hemisphere to stimuli in the speech condition. Novel sounds elicited novelty P3 waves, the amplitude of which for nonhuman sounds was larger in the speech than non-speech condition. The current MMN results imply enhanced processing of linguistically relevant information at the pre-attentive stage and in this way support the domain-specific model of speech perception.

Takegata R., Tervaniemi M., Alku P., Ylinen S., & Näätänen R . ( 2008).

Parameter-specific modulation of the mismatch negativity to duration decrement and increment: evidence for asymmetric processes

Clinical Neurophysiology, 119( 7), 1515-1523.

URL     PMID:18468482      [本文引用: 1]

The mismatch negativity (MMN) component of event-related potentials (ERPs) reflects a change-detection process in the brain. The present study investigated whether stimulus parameters (sound type and duration) exert a differential influence on the MMN for a duration decrement and increment of an equal magnitude. Some asymmetries were reported in the previous studies; yet no systematical study has been conducted.

Taylor J. K., & , Burke D. M . ( 2002).

Asymmetric aging effects on semantic and phonological processes: naming in the picture-word interference task

Psychology and Aging, 17( 4), 662-676.

URL     PMID:12507362      [本文引用: 1]

In 2 experiments, participants named pictures while ignoring auditory word distractors. For pictures with homophone names (e.g., ball), distractors semantically related to the nondepicted meaning (e.g., prom) facilitated naming by top-down phonological connections for young but not for older adults. Slowing from unrelated distractors and facilitation from phonologically related distractors were age invariant except in distractors that were both semantically and phonologically related. Only distractors semantically related to the picture interfered more for older than younger adults. These results ar einconsistent with age-linked deficits in inhibition of irrelevant information from either internal or external sources. Rather, aging affects priming transmission in a connectionist network with asymmetric effects on semantic and phonological connections involved in comprehension and production, respectively.

Wang Y., Yang X., & Liu C . ( 2017).

Categorical perception of Mandarin Chinese tones 1-2 and tones 1-4: effects of aging and signal duration

Journal of Speech, Language, and Hearing Research, 60( 12), 3667-3677.

URL     PMID:29121180      [本文引用: 3]

The purpose of this study was to investigate the aging effect on the categorical perception of Mandarin Chinese tones with varied fundamental frequency (F0) contours and signal duration.

Wang Y., Yang X., Zhang H., Xu L., Xu C., & Liu C . ( 2017).

Aging effect on categorical perception of Mandarin tones 2 and 3 and thresholds of pitch contour discrimination

American Journal of Audiology, 26( 1), 18-26.

URL     PMID:28251239      [本文引用: 2]

The purpose of the study was to examine the aging effect on the categorical perception of Mandarin Chinese Tone 2 (rising F0 pitch contour) and Tone 3 (falling-then-rising F0 pitch contour) as well as on the thresholds of pitch contour discrimination.

Wilson S. M., & Iacoboni M . ( 2006).

Neural responses to non-native phonemes varying in producibility: Evidence for the sensorimotor nature of speech perception

Neuroimage, 33( 1), 316-325.

URL     PMID:16919478      [本文引用: 1]

Neural responses to unfamiliar non-native phonemes varying in the extent to which they can be articulated were studied with functional magnetic resonance imaging (fMRI). Both superior temporal (auditory) and precentral (motor) areas were activated by passive speech perception, and both distinguished non-native from native phonemes, with greater signal change in response to non-native phonemes. Furthermore, speech-responsive motor regions and superior temporal sites were functionally connected. However, only in auditory areas did activity covary with the producibility of non-native phonemes. These data suggest that auditory areas are crucial for the transformation from acoustic signal to phonetic code, but the motor system also plays an active role, which may involve the internal generation of candidate phonemic categorizations. These 'motor' categorizations would then be compared to the acoustic input in auditory areas. The data suggest that speech perception is neither purely sensory nor motor, but rather a sensorimotor process.

Xi J., Zhang L., Shu H., Zhang Y., & Li P . ( 2010).

Categorical perception of lexical tones in Chinese revealed by mismatch negativity

Neuroscience, 170( 1), 223-231.

URL     PMID:20633613      [本文引用: 4]

The present study investigated the neurophysiological correlates of categorical perception of Chinese lexical tones in Mandarin Chinese. Relative to standard stimuli, both within- and across-category deviants elicited mismatch negativity (MMN) in bilateral frontal-central recording sites. The MMN elicited in the right sites was marginally larger than in the left sites, which reflects the role of the right hemisphere in acoustic processing. At the same time, relative to within-category deviants, the across-category deviants elicited larger MMN in the left recording sites, reflecting the long-term phonemic traces of lexical tones. These results provide strong neurophysiological evidence in support of categorical perception of lexical tones in Chinese. More important, they demonstrate that acoustic and phonological information is processed in parallel within the MMN time window for the perception of lexical tones. Finally, homologous nonspeech stimuli elicited similar MMN patterns, indicating that lexical tone knowledge influences the perception of nonspeech signals.

Yang X., Wang Y., Xu L., Zhang H., Xu C., & Liu C . ( 2015).

Aging effect on Mandarin Chinese vowel and tone identification

The Journal of The Acoustical Society of America, 138( 4), 411-416.

URL     PMID:26520353      [本文引用: 3]

Mandarin Chinese speech sounds (vowels × tones) were presented to younger and older Chinese-native speakers with normal hearing. For the identification of vowel-plus-tone, vowel-only, and tone-only, younger listeners significantly outperformed older listeners. The tone 3 identification scores correlated significantly with the age of older listeners. Moreover, for older listeners, the identification rate of vowel-plus-tone was significantly lower than that of vowel-only and tone-only, whereas for younger listeners, there was no difference among the three identification scores. Therefore, aging negatively affected Mandarin vowel and tone perception, especially when listeners needed to process both phonemic and tonal information.

Yu K., Zhou Y., Li L., Su J. A., Wang R., & Li P . ( 2017).

The interaction between phonological information and pitch type at pre-attentive stage: an ERP study of lexical tones

Language, Cognition and Neuroscience, 32( 9), 1164-1175.

[本文引用: 1]

Zhao L . ( 2010).

Experimental course of ERPs

Nanjing, China: Southeast university press.

[本文引用: 1]

[ 赵仑 . ( 2010).

ERPs实验教程

南京: 东南大学出版社.]

[本文引用: 1]

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