失匹配负波研究的主要争论与动向

失匹配负波(MMN)是小概率刺激ERP减大概率刺激ERP的差异负波,可由Oddball范式和多特征选择范式获得。近年研究发现MMN不仅存在于听觉通道,还存在于其他通道,且其波幅可反映自动加工,潜伏期则可反映控制加工。MMN可能反映与错误负波ERN相同或相似的加工过程,MMN反映社会认知加工的观点还需进一步研究。未来研究需整合高时间和空间精度技术,从行为和认知神经科学多层面来开展复杂社会刺激的研究,以便阐明MMN可能反映社会认知加工的性质,并在此基础上增强对MMN与ERN的比较研究。     

汉语普通话声调感知的老年化效应：来自ERP的证据

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。     

视觉工作记忆负载对偏差干扰调控的ERP研究

采用事件相关电位技术（ERPs）,对听视跨通道不同工作记忆负载下偏差干扰效应的加工机制进行研究。当视觉线索50%时,比较有无工作记忆负载条件下偏差干扰效应,分析偏差刺激与标准刺激诱发的差异波,结果发现：（1）存在工作记忆负载和偏差干扰效应;（2）有无工作记忆负载下差异波均出现明显的N1/MMN成分、NP3和RON成分;（3）差异波中N1/MMN成分的平均波幅和潜伏期均没有差异,NP3成分的平均波幅下降;RON成分在平均波幅上没有差异,潜伏期上有工作记忆负载下显著小于无工作记忆负载。研究表明视觉工作记忆负载对偏差干扰调控过程的神经机制并不会因为无关信息与相关信息间冲突竞争增强而改变。     

听觉失匹配负波反映自动加工──感觉道间选择性注意时的新证据

为考察听觉失匹配负波是否反映自动加工,实验改进了视觉和听觉刺激同时呈现的感觉道间选择性注意实验模式,更好地控制了非注意听觉条件。结果发现,在注意与非注意听觉条件下,听觉偏离刺激均诱发出失匹配负波;注意听觉刺激时１４０－１８０ｍｓ的偏离相关负波与非注意时该时程负波的平均波幅之间无显著差异,而注意时１８０－２２０ｍｓ的偏离相关负波的平均波幅大于非注意时同一时程之负波;非注意听觉时失匹配负波的平均波幅和峰潜伏期不受视觉道任务难度的影响,该结果为听觉失匹配负波反映自动加工的观点提供了进一步证据。     

发展性协调障碍儿童视觉通道前注意加工的特点：来自ERP的证据

研究表明发展性协调障碍儿童听觉通道的前注意受损,其视觉通道的前注意加工是否也存在缺陷,从而造成了信息加工困难,目前尚不清楚。本研究旨在探究发展性协调障碍儿童视觉通道前注意加工的特点。从小学二、三、四年级共760名学生中筛选出障碍组20名,同时选择年龄、智力水平相当的对照组儿童20名。采用非注意Oddball任务,以不同颜色图片为实验材料,比较两组儿童前注意信息加工能力。行为结果表明,在注意主任务上,两组儿童的反应时不存在差异;然而,障碍组儿童的准确率显著低于对照组。ERP结果表明,相比于对照组儿童,障碍组儿童的视觉失匹配负波(visual mismatch negativity, vMMN)潜伏期明显延长。同时,本研究还发现运动技能诊断量表得分与vMMN的潜伏期存在显著相关。结果提示,发展性协调障碍儿童视觉通道前注意加工可能存在缺陷;vMMN潜伏期可作为初步评估和判断发展性协调障碍的脑电指标。     

酒精对前注意加工的影响：失匹配负波的证据

前注意是指在注意之前对事物进行该不该注意分析的心理过程, 它对人适应不断变化的环境具有很重要的作用。近年来一些研究者用失匹配负波(Mismatch Negtivity, MMN)作为前注意加工的ERP指标探讨了酒精对人前注意加工的影响, 结果发现：1)急性摄入超过0.3g/kg的酒精, 人的MMN波幅会显著减小, 波峰潜伏期显著延长; 2)长期慢性摄入酒精, 人的MMN不仅表现为波幅减小和波峰潜伏期延迟, 而且在戒断酒精之后, MMN又会逐渐恢复正常; 3)有酒精成瘾家族史的子代的MMN没发现异常。这些研究结果说明酒精的急性和慢性摄入会损害人的前注意加工, 但尚未发现这种损害会影响到下一代的证据。     

时间信息自动加工与控制加工的电生理学指标

类时间信息加工的统一机制问题一直备受研究者关注。新近研究表明失匹配负波（MMN）是与时间信息自动加工有关的ERP成分,关联负变化（CNV）是与控制加工有关的ERP成分,而刺激遗漏电位（OSPs）既与自动加工又与控制加工有关。以三种ERP成分为指标的研究均为时间信息自动加工和控制加工的存在提供了可能的依据。未来研究不应该纠缠于自动加工和控制加工分界点的探究,而是着重从时间全程视角考察时距加工机制的特点。     

选择一致性影响结果评价的ERP研究

本研究通过两个实验探讨了当被试主动做出与他人一致/不一致的选择行为(实验1)或看到他人做出与自己一致/不一致的选择行为(实验2)时,其选择行为的一致性是如何影响结果评价过程的。脑电数据表明在结果评价的早期阶段,无论被试是主动或被动地与他人做出相同选择,这种选择一致性都会放大输赢结果之间的差异:体现在选择一致情况下比不一致情况下诱发更大的d FRN。而在结果评价的晚期阶段,当被试先做出选择之后,看到他人做出与自己不一致的选择时(实验2),相比他人与自己选择一致时,诱发了更大的P3和LPP波幅。说明被试很可能把他人的不一致选择加工为一种冲突。因此投入了更多认知资源来加工这一结果。本研究是一个探索性的创新研究,首次从时间维度上分离了选择行为和结果反馈两个阶段,并提供了选择一致性对结果评价有影响作用的脑电证据。     

2~4岁普通话儿童前注意阶段的声调感知机制

以MMN、p-MMR作为汉语词汇声调感知的神经关联物,探究2~4岁汉语普通话儿童前注意阶段对声调刺激的失匹配响应,关注范畴信息和偏差大小两个因素对儿童感知水平的影响。结果显示:在范畴间大偏差条件下(T1/T3),诱发明显的MMN;在范畴内或小偏差条件下(T3a/T3、T3b/T3、T2/T3),都未诱发显著的MMR。表明:2~4岁普通话儿童正处于声调感知能力的发展过程中,音位信息和声学信息共同影响其声调感知。     

非注意状态下拓扑性质优先加工的电生理学证据

采用ERP技术并运用跨通路延迟反应范式来探讨拓扑性质知觉理论在非注意状态下是否成立,发现存在视觉MMN且视觉系统在非注意状态下对拓扑性质的加工比颜色加工更早,表明与局部属性(颜色)相比,拓扑性质在无意识中优先得到加工,拓扑性质知觉理论在非注意状态下是成立的。     

Effects of dialect on merger perception: ERP and behavioral correlates

Native speakers of a language are often unable to consciously perceive, and have altered neural responses to, phonemic contrasts not present in their language. This study examined whether speakers of dialects of the same language with different phoneme inventories also show measurably different neural responses to contrasts not present in their dialect. Speakers with (n=11) and without (n=11) an American English I/E (pin/pen) vowel merger in speech production were asked to discriminate perceptually between minimal pairs of words that contrasted in the critical vowel merger and minimal pairs of control words while their event-related potential (ERPs) were recorded. Compared with unmerged dialect speakers, merged dialect speakers were less able to make behavioral discriminations and exhibited a reduced late positive ERP component (LPC) effect to incongruent merger vowel stimuli. These results indicate that between dialects of a single language, the behavioral response differences may reflect neural differences related to conscious phonological decision processes.     

Behavioral and electrophysiological evidence for the impact of regional variation on phoneme perception

This event-related potential (ERP) study examined the impact of phonological variation resulting from a vowel merger on phoneme perception. The perception of the /e/-/ε/ contrast which does not exist in Southern French-speaking regions, and which is in the process of merging in Northern French-speaking regions, was compared to the /ø/-/y/ contrast, which is stable in all French-speaking regions. French-speaking participants from Switzerland for whom the /e/-/ε/ contrast is preserved, but who are exposed to different regional variants, had to perform a same-different task. They first heard four phonemically identical but acoustically different syllables (e.g., /be/-/be/-/be/-/be/), and then heard the test syllable which was either phonemically identical to (/be/) or phonemically different from (/bε/) the preceding context stimuli. The results showed that the unstable /e/-/ε/ contrast only induced a mismatch negativity (MMN), whereas the /ø/-/y/ contrast elicited both a MMN and electrophysiological differences on the P200. These findings were in line with the behavioral results in which responses were slower and more error-prone in the /e/-/ε/ deviant condition than in the /ø/-/y/ deviant condition. Together these findings suggest that the regional variability in the speech input to which listeners are exposed affects the perception of speech sounds in their own accent.     

Atypical central auditory speech-sound discrimination in children who stutter as indexed by the mismatch negativity

PurposeRecent theoretical conceptualizations suggest that disfluencies in stuttering may arise from several factors, one of them being atypical auditory processing. The main purpose of the present study was to investigate whether speech sound encoding and central auditory discrimination, are affected in children who stutter (CWS).MethodsParticipants were 10 CWS, and 12 typically developing children with fluent speech (TDC). Event-related potentials (ERPs) for syllables and syllable changes [consonant, vowel, vowel-duration, frequency (F0), and intensity changes], critical in speech perception and language development of CWS were compared to those of TDC.ResultsThere were no significant group differences in the amplitudes or latencies of the P1 or N2 responses elicited by the standard stimuli. However, the Mismatch Negativity (MMN) amplitude was significantly smaller in CWS than in TDC. For TDC all deviants of the linguistic multifeature paradigm elicited significant MMN amplitudes, comparable with the results found earlier with the same paradigm in 6-year-old children. In contrast, only the duration change elicited a significant MMN in CWS.ConclusionsThe results showed that central auditory speech-sound processing was typical at the level of sound encoding in CWS. In contrast, central speech-sound discrimination, as indexed by the MMN for multiple sound features (both phonetic and prosodic), was atypical in the group of CWS. Findings were linked to existing conceptualizations on stuttering etiology.Educational objectives: The reader will be able (a) to describe recent findings on central auditory speech-sound processing in individuals who stutter, (b) to describe the measurement of auditory reception and central auditory speech-sound discrimination, (c) to describe the findings of central auditory speech-sound discrimination, as indexed by the mismatch negativity (MMN), in children who stutter.     

Early and late mismatch negativity elicited by words and speech-like stimuli in children

In auditory perception the brain's attentional and preattentional mechanisms select certain stimuli for preferential processing and filter out irrelevant input. This study investigated nonattentive auditory processing in children. Event-related potentials (ERPs) provide a means to study neural correlates related to language and speech-sound processing. Mismatch negativity (MMN) is an ERP wave that indicates attention-independent perceptual change detection. In this study cortical ERPs were elicited by complex tones, naturally spoken words, and pseudowords, with each stimulus type containing equal acoustical elements. Tones elicited a bifurcated mismatch negativity (MMN), with early MMN (peaking at 150-200 ms) being more dominant. On the other hand, words elicited a strong late MMN, peaking at about 400-450 ms after stimulus onset. The MMN wave form was significantly weaker for pseudowords than for words. The late MMN wave, especially for word differences, was found to reflect summating MMN generators and memory trace formation on gestalt bases. Results suggest that the auditory processing, even nonattended, is highly associated with the cognitive meaning of the stimuli.     

Human central auditory plasticity associated with tone sequence learning

We investigated learning-related changes in amplitude, scalp topography, and source localization of the mismatch negativity (MMN), a neurophysiological response correlated with auditory discrimination ability. Participants (n = 32) underwent two EEG recordings while they watched silent films and ignored auditory stimuli. Stimuli were a standard (probability = 85%) and two deviant (probability = 7.5% each for high [HD] and low [LD]) eight-tone sequences that differed in the frequency of one tone. Between recordings, subjects practiced discriminating the HD or LD from the standard for 6 min. The amplitude of the LD MMN increased significantly across recordings in both groups, whereas the amplitude of the HD MMN did not. The LD was easier to discriminate than was the HD. Thus, practicing either discrimination increased the MMN for the easier discrimination. Learning and changes in the LD MMN amplitude were highly correlated. Source localizations of event-related potentials (ERPs) to all stimuli revealed bilateral sources in superior temporal regions. Compared with the standard ERP, the LD ERP revealed a stronger source in the left superior temporal region in both recordings, whereas the right-sided source became stronger after learning. Consistent with prior studies of auditory plasticity in animals and humans, tone sequence learning induced rapid neurophysiological plasticity in the human central auditory system. The results also suggest that there is asymmetric hemispheric involvement in tone sequence discrimination learning and that discrimination difficulty influences the time course of learning-related neurophysiological changes.     

Musicians and tone-language speakers share enhanced brainstem encoding but not perceptual benefits for musical pitch

Behavioral and neurophysiological transfer effects from music experience to language processing are well-established but it is currently unclear whether or not linguistic expertise (e.g., speaking a tone language) benefits music-related processing and its perception. Here, we compare brainstem responses of English-speaking musicians/non-musicians and native speakers of Mandarin Chinese elicited by tuned and detuned musical chords, to determine if enhancements in subcortical processing translate to improvements in the perceptual discrimination of musical pitch. Relative to non-musicians, both musicians and Chinese had stronger brainstem representation of the defining pitches of musical sequences. In contrast, two behavioral pitch discrimination tasks revealed that neither Chinese nor non-musicians were able to discriminate subtle changes in musical pitch with the same accuracy as musicians. Pooled across all listeners, brainstem magnitudes predicted behavioral pitch discrimination performance but considering each group individually, only musicians showed connections between neural and behavioral measures. No brain-behavior correlations were found for tone language speakers or non-musicians. These findings point to a dissociation between subcortical neurophysiological processing and behavioral measures of pitch perception in Chinese listeners. We infer that sensory-level enhancement of musical pitch information yields cognitive-level perceptual benefits only when that information is behaviorally relevant to the listener.     

Assessing the double phonemic representation in bilingual speakers of Spanish and English: an electrophysiological study

Event Related Potentials (ERPs) were recorded from Spanish-English bilinguals (N = 10) to test pre-attentive speech discrimination in two language contexts. ERPs were recorded while participants silently read magazines in English or Spanish. Two speech contrast conditions were recorded in each language context. In the phonemic in English condition, the speech sounds represented two different phonemic categories in English, but represented the same phonemic category in Spanish. In the phonemic in Spanish condition, the speech sounds represented two different phonemic categories in Spanish, but represented the same phonemic categories in English. Results showed pre-attentive discrimination when the acoustics/phonetics of the speech sounds match the language context (e.g., phonemic in English condition during the English language context). The results suggest that language contexts can affect pre-attentive auditory change detection. Specifically, bilinguals’ mental processing of stop consonants relies on contextual linguistic information.     

Mandarin speech perception by ear and eye follows a universal principle

In this study, the nature of speech perception of native Mandarin Chinese was compared with that of American English speakers, using synthetic visual and auditory continua (from /ba/ to /da/) in an expanded factorial design. In Experiment 1, speakers identified synthetic unimodal and bimodal speech syllables as either /ba/ or /da/. In Experiment 2, Mandarin speakers were given nine possible response alternatives. Syllable identification was influenced by both visual and auditory sources of information for both Mandarin and English speakers. Performance was better described by the fuzzy logical model of perception than by an auditory dominance model or a weighted-averaging model. Overall, the results are consistent with the idea that although there may be differences in information (which reflect differences in phonemic repertoires, phonetic realizations of the syllables, and the phonotactic constraints of languages), the underlying nature of audiovisual speech processing is similar across languages.     

Practice strategies of musicians modulate neural processing and the learning of sound-patterns

Previous studies suggest that pre-attentive auditory processing of musicians differs depending on the strategies used in music practicing and performance. This study aimed at systematically revealing whether there are differences in auditory processing between musicians preferring and not-preferring aural strategies such as improvising, playing by ear, and rehearsing by listening to records. Participants were assigned to aural and non-aural groups according to how much they employ aural strategies, as determined by a questionnaire. The change-related mismatch negativity (MMN) component of event-related brain potentials (ERPs) was used to probe pre-attentive neural discrimination of simple sound features and melody-like patterns. Further, the musicians' behavioral accuracy in sound perception was tested with a discrimination task and the AMMA musicality test. The data indicate that practice strategies do not affect musicians' pre-attentive neural discrimination of changes in simple sound features but do modulate the speed of neural discrimination of interval and contour changes within melody-like patterns. Moreover, while the aural and non-aural groups did not differ in their initial neural accuracy for discriminating melody-like patterns, they differed after a focused training session. A correlation between behavioral and neural measures was also obtained. Taken together, these results suggest that auditory processing of musicians who prefer aural practice strategies differs in melodic contour and interval processing and perceptual learning, rather than in simple sound processing, in comparison to musicians preferring other practice strategies.