视觉语言对听觉障碍人群阅读能力的影响及作用机制

听觉障碍人群由于听觉部分或完全受损, 视觉语言——唇读和手语就成为其阅读能力发展的主要途径。唇读有助于听觉障碍人群形成语音表征, 与词汇知识相互影响, 且可以促进字词阅读及阅读理解的水平; 口语或书面语的加工可以激活相应的手语表征, 手语影响着听觉障碍人群各个层次的阅读能力。未来研究应该关注语音意识、词汇知识等技能在视觉语言影响听觉障碍人群阅读能力过程中的作用机制, 并以视觉语言为中心, 发展出适合汉语听觉障碍人群阅读能力习得的理论模型。     

人声加工的神经机制

人声是人类听觉环境中最熟知和重要的声音, 传递着大量社会相关信息。与视觉人脸加工类似, 大脑对人声也有着特异性加工。研究者使用电生理、脑成像等手段找到了对人声有特异性反应的脑区, 即颞叶人声加工区(TVA), 并发现非人类动物也有类似的特异性加工区域。人声加工主要涉及言语、情绪和身份信息的加工, 分别对应于三条既相互独立又相互作用的神经通路。研究者提出了双通路模型、多阶段模型和整合模型分别对人声的言语、情绪和身份加工进行解释。未来研究需要进一步讨论人声加工的特异性能否由特定声学特征的选择性加工来解释, 并深入探究特殊人群(如自闭症和精神分裂症患者)的人声加工的神经机制。     

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。     

McGurk效应的影响因素与神经基础

McGurk效应(麦格克效应)是典型的视听整合现象, 该效应受到刺激的物理特征、注意分配、个体视听信息依赖程度、视听整合能力、语言文化差异的影响。引发McGurk效应的关键视觉信息主要来自说话者的嘴部区域。产生McGurk效应的认知过程包含早期的视听整合(与颞上皮层有关)以及晚期的视听不一致冲突(与额下皮层有关)。未来研究应关注面孔社会信息对McGurk效应的影响, McGurk效应中单通道信息加工与视听整合的关系, 结合计算模型探讨其认知神经机制等。     

情绪自动化加工的证据与争议

情绪信息对人类的生存非常重要, 研究者一直在探讨情绪产生的本质问题：情绪的产生是“自动”的吗？已有的大量实验证据表明, 情绪可以被快速识别, 甚至在非注意条件下或者无意识条件下, 情绪信息也可以被大脑(尤其是杏仁核)识别。大量实验结果分析了情绪自动化加工的表现, 并探讨了情绪自动化加工的大脑机制：皮层下通路。视觉信息在视网膜接受后, 经上丘脑与枕核传递至杏仁核, 这条通路被称为皮层下通路, 负责情绪信息的快速化加工。但是新的研究对已有的实验范式与技术手段进行了质疑, 反驳情绪的自动化加工, 并质疑皮层下通路存在的可能性。为了进一步理清情绪加工的本质与大脑机制, 今后的研究应当采用更为严格地控制意识、注意资源的实验范式, 以及采用更精确、更高时间与空间分辨率的技术手段。     

文字阅读学习的大脑塑造性机制

文字阅读学习如何塑造了人脑?这是当今语言认知神经科学的热点课题。研究表明,文字阅读学习不仅会增强早期视觉加工能力和重构腹侧视觉通路,还改变了口语脑网络的加工方式和词素-音素转换脑网络的结构。文字阅读学习通过在视觉皮层与口语系统之间创建一个高效自动运作的平台,改变人脑的功能与结构组织。今后的研究需要深入探究视觉词形区(VWFA)的功能特异性及其与语音和语义加工的动态交互作用、汉字阅读学习的大脑可塑性机制和文字识别与面孔加工的竞争性发育机制等重要问题。     

视觉经验缺失对盲人听觉词汇识别的影响

听觉词汇识别包含复杂的认知加工过程。视觉通道受阻的盲人在听觉词汇加工中具有一定听觉补偿优势; 但由于视觉经验的缺失, 盲人对一些视觉相关词(比如颜色词)的语义加工和理解比明眼人弱。未来的研究应对词汇的视觉相关性进行分类讨论; 对音、形、义等多层面及其神经生理机制进行深入探究, 发展符合盲人感知特点的听觉词汇加工模型; 并拓展不同年龄段的发展性研究。最终, 揭示视觉经验缺失对盲人听觉词汇识别影响机制的全貌。     

听觉预测编码：对声音重复和变化的神经反应

预测编码被认为是脑与复杂环境交互的重要机制之一, 有效感知外界环境并对未来事件做出预测, 对个体生存有着至关重要的意义。人类大脑会基于感觉输入以迭代的方式持续优化表征外部环境的内部模型, 并不断预测接下来的感觉输入。以听觉模态为例, 人类及动物对声音重复和听觉变化的神经反应(如失匹配负波和刺激特异性适应)是大脑预测编码的重要体现, 表现为重复抑制和预测误差。结合人类和动物模型在此理论框架下开展跨物种研究将有助于加深我们对听觉加工, 甚至是大脑工作机制的认识。     

视听整合加工及其神经机制

通常人们接收到来自不同感觉通道的信息时, 首先在大脑中各个分离的区域单独进行加工处理, 而后在多感官区进行整合。前人关于言语感知中视听整合加工的神经成像研究认为, 视觉和听觉信息能够相互影响; 两者进行整合的关键区域是人脑左后侧的颞上沟, 其整合效应受时间和空间因素的限制。未来的研究应致力于建立更加合理的实验范式和数据分析方法来探讨整合加工的脑区机制, 把多感官整合研究进一步延伸到更加复杂的领域。     

视觉适应及其神经机制

视适应使得视觉系统可以连续地根据外界环境的变化做出调整, 改善了对世界的感知。研究提示, 适应影响了对许多基本的视觉属性的加工, 诸如亮度、对比度、运动、颜色等, 也包括对复杂的刺激如面孔等。视适应发生于视觉加工流的多个阶段, 从视网膜到初级视觉皮层以及之后的脑区(例如纹外皮层, 梭状回面孔区)。关于视适应的机制解释, 已从早期的神经元反应疲劳解释发展成当今更流行的标准化模型理论等。最近的适应研究证明, 视觉适应由时间尺度上快慢不同的多重机制控制, 这被认为赋予了视觉系统有效应对环境中不同时间尺度的变化的能力。     

工作记忆负荷、形状干扰对聋人与听力正常人注意捕获影响的眼动研究

通过记录和分析被试的行为和眼动指标,本研究试图探讨不同工作记忆负荷下,形状干扰对聋人与听力正常人不同视野位置上刺激信息捕获注意的异同。研究结果表明：（1）形状干扰刺激虽然没有影响被试视觉加工的认知绩效,但被试的眼动模式会由于工作记忆负荷的改变而改变,高工作记忆负荷时,有形状干扰的注视次数高于无形状干扰。（2）工作记忆负荷、视野位置影响被试视觉加工任务的完成,被试在不同视野位置的加工过程表现出不一致的眼动模式。（3）聋人视觉加工在高工作记忆负荷时存在一定的劣势,但其对不同视野位置的信息加工及形状干扰所产生的注意捕获效应与听力正常人一致。     

The effect of auditory input on cerebral laterality

Cerebral laterality was examined for third-, fourth-, and fifth-grade deaf and hearing subjects. The experimental task involved the processing of word and picture stimuli presented singly to the right and left visual hemifields. The analyses indicated the deaf children were faster than the hearing children in overall processing efficiency, and that they performed differently in regard to hemispheric lateralization. The deaf children processed the stimuli more efficiently in the right hemisphere, while the hearing children demonstrated a left-hemisphere proficiency. This finding is discussed in terms of the hypothesis that cerebral lateralization is influenced by auditory processing.     

Cerebral asymmetry in the perception of American sign language.

American Sign Language (ASL) offers a valuable opportunity for the study of cerebral asymmetries, since it incorporates both language structure and complex spatial relations: processing the former has generally been considered a left-hemisphere function, the latter, a right-hemisphere one. To study such asymmetries, congenitally deaf, native ASL users and normally-hearing English speakers unfamiliar with ASL were asked to identify four kinds of stimuli: signs from ASL, handshapes never used in ASL, Arabic digits, and random geometric forms. Stimuli were presented tachistoscopically to a visual hemifield and subjects manually responded as rapidly as possible to specified targets. Both deaf and hearing subjects showed left-visual-field (hence, presumably right-hemisphere) advantages to the signs and to the non-ASL hands. The hearing subjects, further, showed a left-hemisphere advantage to the Arabic numbers, while the deaf subjects showed no reliable visual-field differences to this material. We infer that the spatial processing required of the signs predominated over their language processing in determining the cerebral asymmetry of the deaf for these stimuli.     

Left-Hemisphere Dominance for Motion Processing in Deaf Signers

Evidence from neurophysiological studies in animals as well as humans has demonstrated robust changes in neural organization and function following early-onset sensory deprivation. Unfortunately, the perceptual consequences of these changes remain largely unexplored. The study of deaf individuals who have been auditorily deprived since birth and who rely on a visual language (i.e., American Sign Language, ASL) for communication affords a unique opportunity to investigate the degree to which perception in the remaining, intact senses (e.g., vision) is modified as a result of altered sensory and language experience. We studied visual motion perception in deaf individuals and compared their performance with that of hearing subjects. Thresholds and reaction times were obtained for a motion discrimination task, in both central and peripheral vision. Although deaf and hearing subjects had comparable absolute scores on this task, a robust and intriguing difference was found regarding relative performance for left-visual-field (LVF) versus right-visual-field (RVF) stimuli: Whereas hearing subjects exhibited a slight LVF advantage, the deaf exhibited a strong RVF advantage. Thus, for deaf subjects, the left hemisphere may be specialized for motion processing. These results suggest that perceptual processes required for the acquisition and comprehension of language (motion processing, in the case of ASL) are recruited (or "captured") by the left, language-dominant hemisphere.     

The Short-Term Memory of Profoundly Deaf People for Words,Signs, and Abstract Spatial Stimuli

The short-term memory (STM) of 25 deaf and 20 hearing adults fluent in Australian Sign Language (Auslan) was tested using both free- and serial-recall versions of three tasks. On two tasks, where stimuli were presented as either written words or Auslan signs, hearing subjects performed significantly better than deaf subjects. This difference was attributed to the facility of the hearing subjects in translating these two classes of language-based stimuli into phonological codes, which have a preferred status in STM. On the third, language-free task, which was an adaptation of the Corsi Blocks test, the deaf and hearing subjects performed at comparable levels, indicating that differences in their STM became evident only with the introduction of language-based factors. Analyses restricted to the deaf subjects showed that performances on the language-based STM tasks correlated positively with scores on a reading comprehension test. Also, deaf subjects who reported an oral education outperformed their counterparts, who reported a total communication (oral plus signed English) education on the language-based STM tasks. Thus, for this diverse adult deaf sample, proficiency in STM for language-based material, skill in reading, and report of an oral rather than total communication education appear to covary.     

Tactile Enumeration and Embodied Numerosity Among the Deaf

Representations of the fingers are embodied in our cognition and influence performance in enumeration tasks. Among deaf signers, the fingers also serve as a tool for communication in sign language. Previous studies in normal hearing (NH) participants showed effects of embodiment (i.e., embodied numerosity) on tactile enumeration using the fingers of one hand. In this research, we examined the influence of extensive visuo-manual use on tactile enumeration among the deaf. We carried out four enumeration task experiments, using 1–5 stimuli, on a profoundly deaf group (n = 16) and a matching NH group (n = 15): (a) tactile enumeration using one hand, (b) tactile enumeration using two hands, (c) visual enumeration of finger signs, and (d) visual enumeration of dots. In the tactile tasks, we found salient embodied effects in the deaf group compared to the NH group. In the visual enumeration of finger signs task, we controlled the meanings of the stimuli presentation type (e.g., finger-counting habit, fingerspelled letters, both or neither). Interestingly, when comparing fingerspelled letters to neutrals (i.e., not letters or numerical finger-counting signs), an inhibition pattern was observed among the deaf. The findings uncover the influence of rich visuo-manual experiences and language on embodied representations. In addition, we propose that these influences can partially account for the lag in mathematical competencies in the deaf compared to NH peers. Lastly, we further discuss how our findings support a contemporary model for mental numerical representations and finger-counting habits.     

Deaf poor readers' pattern reversal visual evoked potentials suggest magnocellular system deficits: implications for diagnostic neuroimaging of dyslexia in deaf individuals

Deafness and developmental dyslexia in the same individual may jointly limit the acquisition of reading skills for different underlying reasons. A diagnostic marker for dyslexia in deaf individuals must therefore detect the presence of a neurobiologically based dyslexia but be insensitive to the ordinary developmental influences of deafness on reading skill development. We propose that the functional status of the magnocellular visual system in deaf individuals is potentially such a marker. We present visual evoked potential (VEP) evidence that adult deaf poor readers as a group display magnocellular system deficits not observed in deaf good readers. We recorded pattern-reversal VEPs to high- and low-contrast checkerboard stimuli, which primarily activate the parvocellular and magnocellular pathways, respectively. Principal components analysis of these VEPs produced a time-ordered sequence of three early components that displayed interactions between reading skill and stimulus contrast across multiple scalp recording sites. Deaf poor readers displayed an abnormal absence of contrast-sensitive VEP responses at occipital sites during early visual processing (75 ms poststimulus), whereas deaf good readers showed the expected early contrast-sensitive occipital VEP responses. Over the subsequent 225 ms, the occipital VEP behavior of deaf poor readers closely approximated that of deaf good readers. The VEPs of deaf poor readers were apparently characterized by delayed responses to low-contrast stimuli compared with deaf good readers. Our results provide the first neurobiological evidence that developmental dyslexia exists within the deaf population and is associated with the same underlying magnocellular system deficit that has been observed in hearing dyslexics. Direct neural imaging of the status of the magnocellular visual system in deaf individuals may eventually provide differential diagnosis of developmental dyslexia in the deaf population.     

听觉障碍对聋人视觉功能影响的理论之争：缺陷还是补偿？

听觉通道受损,是否会影响聋人的视觉功能？有三种理论对此做出了解释。缺陷理论：聋人视觉功能存在缺陷,包括听觉脚手架假说和劳动分工假说。补偿理论：聋人视觉功能会表现出增强,包括响应增强假说、知觉增强假说、超通道功能假说和背侧通路假说。整合理论：聋人视觉功能既可能表现为缺陷,也可能表现为增强,与实验任务和被试年龄有关。本文评述了听觉障碍对聋人视觉功能影响的三种理论,并对其今后的发展趋势进行了展望。     

Sensory temporal processing in adults with early hearing loss

This study examined tactile and visual temporal processing in adults with early loss of hearing. The tactile task consisted of punctate stimulations that were delivered to one or both hands by a mechanical tactile stimulator. Pairs of light emitting diodes were presented on a display for visual stimulation. Responses consisted of YES or NO judgments as to whether the onset of the pairs of stimuli was perceived simultaneously or non-simultaneously. Tactile and visual temporal thresholds were significantly higher for the deaf group when compared to controls. In contrast to controls, tactile and visual temporal thresholds for the deaf group did not differ when presentation locations were examined. Overall findings of this study support the notion that temporal processing is compromised following early deafness regardless of the spatial location in which the stimuli are presented.     

不同感觉通道词汇影响聋生汉字加工的实验研究

本研究为考察聋生在接受不同感觉通道词汇时的汉字加工特点和听觉编码所起的作用,采用听觉词汇、视觉词汇和其他感觉词汇等三类词汇为实验材料,对手语聋生组、口语聋生组以及大学生进行了新旧词汇判断、包含与排除两个实验。实验表明,聋生在汉字加工中不仅使用视觉编码,而且无意识地、自动地使用了听觉编码,这在内隐测验中可表现出来。由此可推断,聋生汉字加工困难的原因在于有意识地使用听觉编码的能力较低。