大脑电刺激在听觉语言加工研究中的应用

大脑电刺激是历史悠久但近年来才广泛应用在人类被试上的实验技术。通过对颅内刺激位点进行电刺激, 并分析引发的暂时性行为功能变化和记录位点的电位活动, 大脑电刺激技术可以揭示认知加工过程中脑区内的功能作用与脑区间的有效连接。通过对听觉语言加工过程相关的丘脑、听觉皮层、高级语言皮层进行电刺激, 现有研究发现了各个脑区的不同功能特点以及不同脑区间的信息传递机制, 为进一步探索听觉语言加工的神经机制提供了新的视角。     

言语中的音高信息声学语音学加工的大脑偏侧化

旨在探讨言语中音高信息自下而上的声学语音学加工的神经机制和大脑偏侧化.发现,被动听和主动判断任务分别激活了颞叶和额叶,激活在颞极、颞上回和额下回眶部表现出明显的右侧优势.结果表明,对言语中音高信息自下而上的声学语音学加工主要是右脑的功能,言语与非言语信号的音高信息可能有相似的加工机制,支持Gandour等提出的理论.     

聋人唇读的大脑机制研究

特定区域整合模型与信息传输接替模型提供了聋人唇读不同的大脑机制,前者认为聋人唇读是由特定大脑皮层(如TSS．后扣带回等)加工的结果,听觉皮层并未参与视觉语言认知加工;后者认为聋人唇读的大脑机制与正常人无声唇读的大脑机制基本相似,是通过皮层下的连接区域(如屏状核)激活了视觉皮层、听觉皮层等。但更多的证据支持信息传输接替模型。聋人的听觉皮层具有可塑性,早期的语言经验对言语加工神经通路的建立具有很大的影响。     

嗓音模仿认知神经加工的多阶段模型

嗓音模仿是言语交流中关键的认知过程,即对话一方(说话人)将感知到的另一方(目标说话人)的嗓音信号映射为自己的发声器官运动表征,达到发声器官运动表征复制和目标说话人嗓音再现的目的。成像结果表明,嗓音模仿的认知加工涉及颞上回到左侧额下回,再到发声相关初级运动皮层的神经网络,并且基底神经节在该网络中发挥协调作用。嗓音辨别能力、嗓音信号至发声运动表征的映射能力以及发声器官肌肉的控制能力的个体差异都会影响嗓音模仿的认知加工。未来研究应该考虑将嗓音模仿与发声障碍以及侵入电极技术结合起来,旨在共同揭示脑与行为的因果机制,并进一步应用于言语的终身发展、认知可塑性以及言语预期领域。     

从不平衡的视觉输入到不平衡的视觉注意：探寻短时程眼优势可塑性的神经机制

在个体视觉系统的发展过程中,视觉系统的结构与功能会受到视觉经验和内外部环境的影响而发生改变,这被称为视觉可塑性。视觉可塑性在出生后的发育关键期内达到峰值。虽然成年期视皮层神经环路的结构功能趋于稳定,但有越来越多的研究表明成年人视皮层中仍保留着一定程度的可塑性,其中的典型代表就是眼优势的可塑性。最近十几年的研究发现,短时程操控成年人的各种视觉输入信息,乃至调节两眼间注意资源的分配,都可以引起成年人眼优势发生偏移。然而,两者调节眼优势的神经机制可能并不相同。视觉输入对成年人眼优势的调节可能主要反映了视觉皮层的稳态可塑性机制;而注意对眼优势的影响则是一种高级加工对初级视觉皮层的反馈调节,目前可以用拮抗神经元的适应机制来作解释。未来研究可以寻找更加直接的证据来支持这一解释,此外也应重点关注注意与视觉输入之间会如何交互影响成年人眼优势。     

脑干诱发电位在言语感知研究中的应用

脑干诱发电位是一种考察听觉脑干加工声音信号时神经活动的非侵入性技术, 近年来被广泛用于探索言语感知的神经基础。相关研究主要集中在考察成年人和正常发展儿童语音编码时脑干的活动特征及发展模式, 探讨发展性阅读障碍及其他语言损伤的语音编码缺陷及其神经表现等方面。在已有研究的基础上进一步探索初级语音编码和高级言语加工之间的相互作用机制, 考察阅读障碍的底层神经基础将成为未来该技术在言语感知研究中应用的重点。     

听觉障碍人群的言语机制

对听觉障碍人群言语机制的研究,提供了独特的视角来探讨人脑内语言专门化系统的组织。该回顾了近年来在该领域内进行的损伤研究及功能性成像研究,着重综述了三个问题：(1)左右半球损伤造成的手语失语症的特点;(2)手语加工过程中左右半球的激活模式;(3)先天聋被试在阅读唇语过程中的脑内激活模式及后部扣带皮层在唇语阅读过程中的可能作用。     

言语次级干扰任务对客体与空间信息保持的影响

通过3个行为实验,以44名大学生或研究生为被试,考察了言语次级干扰任务是否对不同言语命名难度的客体与空间工作记忆信息的保持产生选择性干扰。研究发现:无论记忆对象是言语命名困难的客体信息,还是言语命名容易的客体信息,无论探测刺激是图形形式,还是词语形式,言语次级干扰任务都对客体信息的保持产生选择性干扰;但言语次级干扰任务对空间信息保持的影响,在不同条件下则表现出不同的特点。实验结果表明客体工作记忆自动、强制性地使用言语编码和保持机制,而空间工作记忆信息的保持是否由言语编码参与则受到其他因素的影响。     

汉语母语者视听双通道言语知觉的特点及发展研究

以30名小学二年级学生2、4名小学五年级学生和29名大学一年级学生为被试,运用McGurk效应研究范式对汉语母语者视听双通道言语知觉的表现特点、发展趋势等问题进行了探讨,三个年龄阶段被试均接受纯听和视听两种条件下的测查,被试的任务是出声报告自己听到的刺激。结果发现:(1)汉语为母语的二年级小学生、五年级小学生和大学生在自然听力环境下的单音节加工中都受到视觉线索的影响,表现出了McGurk效应;(2)二年级小学生、五年级小学生和大学生受视觉言语影响的程度,也就是McGurk效应的强度没有显著差异,没有表现出类似英语母语者的发展趋势。该结果支持了McGurk效应"普遍存在"的假说。     

数字加工的脑功能成像研究进展及其皮层定位

数字加工是人类最重要的认知功能之一。当前的脑功能成像研究有助于对数字加工与皮层之间的联系进行更精确的定位。基于对上世纪80年代来有关数字加工脑功能成像研究的主要成果的回顾,尤其是一些重要区域,如双侧顶叶与前额叶等在数字加工中的地位与作用,以及不同脑区之间的关系进行了探讨,并对一个广泛运用的数字加工神经机制模型进行了简要评述。在此基础上,对数字加工的皮层定位问题进行了简要的总结。     

Do deaf individuals see better?

The possibility that, following early auditory deprivation, the remaining senses such as vision are enhanced has been met with much excitement. However, deaf individuals exhibit both better and worse visual skills than hearing controls. We show that, when deafness is considered to the exclusion of other confounds, enhancements in visual cognition are noted. The changes are not, however, widespread but are selective, limited, as we propose, to those aspects of vision that are attentionally demanding and would normally benefit from auditory-visual convergence. The behavioral changes are accompanied by a reorganization of multisensory areas, ranging from higher-order cortex to early cortical areas, highlighting cross-modal interactions as a fundamental feature of brain organization and cognitive processing.     

没听到？“听”到！——来自听觉表象神经机制研究的证据

近年来听觉表象开始得到关注,相关研究包括言语声音、音乐声音、环境声音的听觉表象三类。本文梳理了认知神经科学领域对上述三种听觉表象所激活的脑区研究,比较了听觉表象和听觉对应脑区的异同,并展望了听觉表象未来的研究方向。     

Electrophysiologic Manifestations of Impaired Temporal Lobe Auditory Processing in Verbal Auditory Agnosia

The present study examined the extent to which verbal auditory agnosia (VAA) is primarily a phonemic decoding disorder, as contrasted to a more global defect in acoustic processing. Subjects were six young adults who presented with VAA in childhood and who, at the time of testing, showed varying degrees of residual auditory discrimination impairment. They were compared to a group of young adults with normal language development matched for age and gender. Cortical event-related potentials (ERPs) were recorded to tones and to consonant-vowel stimuli presented in an "oddball" discrimination paradigm. In addition to cortical ERPs, auditory brainstem responses (ABRs) and middle latency responses (MLRs) were recorded. Cognitive and language assessments were obtained for the VAA subjects. ABRs and MLRs were normal. In comparison with the control group, the cortical ERPs of the VAA subjects showed a delay in the N1 component recorded over lateral temporal cortex both to tones and to speech sounds, despite an N1 of normal latency overlying the frontocentral region of the scalp. These electrophysiologic findings indicate a slowing of processing of both speech and nonspeech auditory stimuli and suggest that the locus of this abnormality is within the secondary auditory cortex in the lateral surface of the temporal lobes.     

The functional neuroanatomy of prelexical processing in speech perception

In this paper we attempt to relate the prelexical processing of speech, with particular emphasis on functional neuroimaging studies, to the study of auditory perceptual systems by disciplines in the speech and hearing sciences. The elaboration of the sound-to-meaning pathways in the human brain enables their integration into models of the human language system and the definition of potential auditory processing differences between the two cerebral hemispheres. Further, it facilitates comparison with recent developments in the study of the anatomy of non-human primate auditory cortex, which has very precisely revealed architectonically distinct regions, connectivity, and functional specialization.     

Speech Perception Within an Auditory Cognitive Science Framework

ABSTRACT— The complexities of the acoustic speech signal pose many significant challenges for listeners. Although perceiving speech begins with auditory processing, investigation of speech perception has progressed mostly independently of study of the auditory system. Nevertheless, a growing body of evidence demonstrates that cross-fertilization between the two areas of research can be productive. We briefly describe research bridging the study of general auditory processing and speech perception, showing that the latter is constrained and influenced by operating characteristics of the auditory system and that our understanding of the processes involved in speech perception is enhanced by study within a more general framework. The disconnect between the two areas of research has stunted the development of a truly interdisciplinary science, but there is an opportunity for great strides in understanding with the development of an integrated field of auditory cognitive science.     

The effect of gender on the N1-P2 auditory complex while listening and speaking with altered auditory feedback

The effect of gender on the N1-P2 auditory complex was examined while listening and speaking with altered auditory feedback. Fifteen normal hearing adult males and 15 females participated. N1-P2 components were evoked while listening to self-produced nonaltered and frequency shifted /a/ tokens and during production of /a/ tokens during nonaltered auditory feedback (NAF), frequency altered feedback (FAF), and delayed auditory feedback (DAF; 50 and 200 ms). During speech production, females exhibited earlier N1 latencies during 50 ms DAF and earlier P2 latencies during 50 ms DAF and FAF. There were no significant differences in N1-P2 amplitudes across all conditions. Comparing listening to active speaking, N1 and P2 latencies were earlier among females, with speaking, and under NAF. N1-P2 amplitudes were significantly reduced during speech production. These findings are consistent with the notions that speech production suppresses auditory cortex responsiveness and males and females process altered auditory feedback differently while speaking.     

Developmental shifts in children's sensitivity to visual speech: a new multimodal picture-word task

This research developed a multimodal picture-word task for assessing the influence of visual speech on phonological processing by 100 children between 4 and 14 years of age. We assessed how manipulation of seemingly to-be-ignored auditory (A) and audiovisual (AV) phonological distractors affected picture naming without participants consciously trying to respond to the manipulation. Results varied in complex ways as a function of age and type and modality of distractors. Results for congruent AV distractors yielded an inverted U-shaped function with a significant influence of visual speech in 4-year-olds and 10- to 14-year-olds but not in 5- to 9-year-olds. In concert with dynamic systems theory, we proposed that the temporary loss of sensitivity to visual speech was reflecting reorganization of relevant knowledge and processing subsystems, particularly phonology. We speculated that reorganization may be associated with (a) formal literacy instruction and (b) developmental changes in multimodal processing and auditory perceptual, linguistic, and cognitive skills.     

A case of cortical deafness: Clinical and electrophysiological data

A patient suffering from a primary myocardiopathy is suddenly no longer able to recognize speech and environmental sounds, in spite of good peripheral hearing; he remains able to speak, read, and write. The C.T. scan shows lesions involving both supratemporal planes. The cortical sensory deficit documented by the absence of late acoustic evoked potentials leads to a diagnosis of cortical deafness rather than of auditory agnosia.     

Visual processing speed: effects of auditory input on visual processing

The ability to process simultaneously presented auditory and visual information is a necessary component underlying many cognitive tasks. While this ability is often taken for granted, there is evidence that under many conditions auditory input attenuates processing of corresponding visual input. The current study investigated infants' processing of visual input under unimodal and cross-modal conditions. Results of the three reported experiments indicate that different auditory input had different effects on infants' processing of visual information. In particular, unfamiliar auditory input slowed down visual processing, whereas more familiar auditory input did not. These results elucidate mechanisms underlying auditory overshadowing in the course of cross-modal processing and have implications on a variety of cognitive tasks that depend on cross-modal processing.     

Auditory language comprehension: an event-related fMRI study on the processing of syntactic and lexical information

The functional specificity of different brain areas recruited in auditory language processing was investigated by means of event-related functional magnetic resonance imaging (fMRI) while subjects listened to speech input varying in the presence or absence of semantic and syntactic information. There were two sentence conditions containing syntactic structure, i.e., normal speech (consisting of function and content words), syntactic speech (consisting of function words and pseudowords), and two word-list conditions, i.e., real words and pseudowords. The processing of auditory language, in general, correlates with significant activation in the primary auditory cortices and in adjacent compartments of the superior temporal gyrus bilaterally. Processing of normal speech appeared to have a special status, as no frontal activation was observed in this case but was seen in the three other conditions. This difference may point toward a certain automaticity of the linguistic processes used during normal speech comprehension. When considering the three other conditions, we found that these were correlated with activation in both left and right frontal cortices. An increase of activation in the planum polare bilaterally and in the deep portion of the left frontal operculum was found exclusively when syntactic processes were in focus. Thus, the present data may be taken to suggest an involvement of the left frontal and bilateral temporal cortex when processing syntactic information during comprehension.