Language learning disabilities: integrating research approaches

Developmental language learning impairments affect 10 to 20% of children and increase their risk of later literacy problems (dyslexia) and psychiatric disorders. Both oral- and written-language impairments have been linked to slow neural processing, which is hypothesized to interfere with the perception of speech sounds that are characterized by rapid acoustic changes. Research into the etiology of language learning impairments not only has led to improved diagnostic and intervention strategies, but also has raised fundamental questions about the neurobiological basis of speech, language, and reading, as well as hemispheric lateralization.     

自我概念威胁以及与重要他人的比较共同削弱自我面孔优势效应

内隐积极联想理论(implicit positive association, IPA)认为自我面孔识别以及与之伴随的自我意识激发了自我概念的积极属性, 促进了对自我面孔的识别优势, 因此通过自我概念威胁可以削弱自我面孔识别的优势效应。本研究旨在探讨自我概念威胁以及与重要他人的比较对自我面孔优势效应的共同影响。实验一为自我-朋友对比实验, 10对同性好友(20名被试)在接受完自我概念威胁启动或者非威胁性启动后对自我面孔和朋友面孔进行朝向的判断, 结果发现非威胁性启动后, 自我面孔的优势效应依然存在, 而在自我概念威胁启动后, 自我面孔优势效应消失。实验二为自我-陌生人对比实验, 另外20名被试在接受完自我概念威胁启动或者非威胁性启动后, 对自我面孔和陌生人面孔进行朝向的判断, 结果发现, 无论是自我概念威胁启动还是非威胁性启动后, 自我面孔识别优势效应都依然存在。两个实验的结果均主要体现在用左手进行反应的时候。结果表明：自我概念威胁以及与重要他人的比较共同削弱自我面孔优势效应; 而左手效应的发生似乎表明了大脑右半球对自我面孔识别的主导和调节作用。     

默读汉字词的脑功能偏侧化成像研究

采用读词名的方法 ,对 12名正常大学生 ,运用功能性磁共振成像技术 (fMRI) ,研究了汉字词及假词视觉识别时的脑功能偏侧化现象。实验结果表明 ,汉字词激活左下额区 (BA4 5 )以及右颞叶 (BA2 1、2 2 )、右枕叶 (BA18) ,而假词除额区外表现出广泛的激活。此结果显示除左脑半球与汉字词加工密切相关外 ,右脑半球在汉字词加工中有一定参与但其确切作用有待进一步研究     

The Hécaen-Zangwill legacy: Hemispheric dominance examined

The research of Henry Hécaen and Oliver Zangwill on patients with unilateral brain lesions in the later 1940s and early 1950s ushered in the modern era of investigation of hemispheric cerebral dominance. The field of inquiry expanded far beyond language and visual perception to encompass audition, somesthesis, motor performance, attentional processes, emotionality, and psychiatric disorders. The hundreds of studies dealing with the topic indicate that hemispheric dominance is not an all-or-none phenomenon and that, to some degree, it is an unstable phenomenon dependent upon bihemispheric factors. The basic cognitive processes that are preferentially mediated by each hemisphere and the factors that produce changes in performance still require adequate definition.Adapted from an invited address, Division 40, 1991 APA Convention, San Francisco.     

工作记忆中汉字与空间的分离及动态优势半球的ERP效应

测量了14名正常被试完成延迟匹配任务时的事件相关脑电位(ERP)。在刺激消失后的延迟阶段,汉字任务和空间任务均在头皮中前部额区产生P260和晚期正成分(LPC), 在头皮后部顶枕区产生N150和晚期负成分(LNC)。汉字任务的P260表现出右脑优势, 400-800ms时LPC转变为与空间任务相比较的汉字左脑相对优势。空间任务的P260在左右脑无差异,400-800ms时LPC转变为右脑优势。头皮后部无显著差异。本研究提供了工作记忆中汉字与空间信息保持的分离及其优势脑动态变化的ERP证据。     

中国学生的自我面孔识别

已有研究表明大脑右半球具有自我面孔再认的优势。为了进一步验证这个观点,该研究使用面孔识别任务,以13名右利手的中国大学生为被试,测量被试对morphing面孔的左右手反应差异。给被试呈现第一张面孔向第二张面孔的morphing过程,当被试看到morphing的面孔更像第二张面孔时报告停止。研究有两个morphing过程：一个为由自我面孔向名人面孔morphing,另一个为好朋友面孔（熟悉的）向名人面孔morphing。结果表明当用左手反应时,被试倾向于把morphing的面孔识别为自己,研究中自我面孔再认的左手优势与已有的发现一致。另外,研究还发现在一定trials条件下,熟悉面孔再认也具有左手优势,这一结果与西方被试的结果不一致,但东西方被试对熟悉面孔再认的差异与独立型自我和互倚型自我的观点一致。该文认为神经心理学有关自我的研究可能需要考虑文化和情境的复杂性。     

Letter Position Coding with Fred Astaire: Inversion of Letter Position Substitution Effects in Reverse Spelled Words

The effects of letter substitutions have been linked to their position within a word (letter position effects). The current study expanded upon previous research by examining letter-position effects for letter substitutions using forward- and reverse-spelled word primes. Often substituting a letter on one side of a word will have a stronger impact on performance than substituting a letter on the other side of a word. In three experiments it was revealed that the letter-position effects of substitutions changed places when words were spelled backwards. This occurred when both the target and prime were spelled backwards. This was evidence of a congruency effect of letter-position priming. The ramifications of these results for word recognition and transfer are discussed. However, the need for future research should focus on the possibility of an inversion process/mechanism.     

新颖语义联结形成的右半球优势效应

新颖语义联结形成是创造性思维的重要加工过程。采用谜题型歇后语为材料,直接操控语义联结的新颖性,通过两个实验考察汉语新颖语义联结形成的神经机制。实验1采用fMRI记录谜题型歇后语阅读理解过程的神经活动,结果显示相对于寻常语义关联条件,新颖语义关联条件更强地激活了右侧颞上回,该脑区可能与新颖语义信息的激活有关。实验2采用ERP技术在语义关联性判断任务中考察新颖语义联结形成神经加工的时空特征,结果显示相对于寻常语义关联条件,新颖语义关联条件在右侧颞区和右侧额区诱发了更正的晚期正成分,可能分别反映了新颖语义信息的激活以及选择与整合。研究结果支持了新颖语义联结形成的右半球加工优势效应。     

A New Tactile Illusion: Temporal Limits on the Processing of Spatiotemporal Patterns

A novel illusion was observed when 12 tactile point-stimulators arranged in a circle were sequentially activated so that each quadrant was first traced in a clockwise manner, then counterclockwise, and again in a clockwise manner, after which the next quadrant was similarly traced. Under certain temporal conditions this stimulus pattern was experienced as a point moving through an overall circular path but looping inwardly about once per quadrant. The effects of variations in rate of presentation of such stimuli were investigated by having subjects make drawings of their perceptual experiences. Three skin surfaces were used (palm, fingers, and forearm), and all produced similar results except for lower confidence and reliability of drawings made from forearm stimulation. Pattern presentation rate, however, had a consistent and powerful effect, with the looping illusion most frequently observed at rates around 25 pattern points per s and with different perceptual organizations dominating as rates departed widely from this optimum. The illusory perceptual organizations were interpreted as compromises between past and present stimulation necessitated by the relative slowness of tactile processing of spatio-temporal patterns.