Sentence processing deficits in two Cantonese aphasic patients

This paper reports the performances of two Cantonese aphasics on tasks examining their sentence processing deficits. The data on sentence comprehension show that thematically noncanonical sentences, full passives, and subject-gap sentences present greater difficulty to these patients than canonical sentences, truncated passives, and object-gap sentences, respectively. These patterns are consistent with previous observations on Chinese aphasics and are expected given the structural differences between Chinese and English. In a Cantonese grammaticality judgment test, a set of structures are identified that can elicit clear judgments from normal subjects and aphasics, contrary to the claim that grammaticality judgments in Chinese are probabilistic and fragile. Most interestingly, the patients' overall performance patterns reveal a double dissociation between sentence comprehension and judgment of sentence well-formedness, suggesting that the two tasks are supported by independent processing mechanisms.     

Understanding Disorders in Agrammatic Patients: Capacity or Structural Deficits?

Several hypotheses have been advanced in recent years to understand difficulties in agrammatic patients. Some of them are of a structural kind, as the deficiency is said to lie in some of the linguistic system components. Others are of a functional type, as it is stated that the problem of these patients lies in the loss of processing capacity.Using the existence of a syntactic type of structure in Spanish, that active sentences do not follow the canonical S-V-O order, we will try to prove in this article whether agrammatic patients' problems are due to memory span loss or to one of the syntactic process mechanisms. To this end, the performances of three groups of patients are contrasted. Agrammatic, anomic, and normal Spanish speakers are given several tasks of sentence–picture matching and tests of memory span.Results show that agrammatic patients have specific difficulties processing certain syntactical structures; however, their memory deficiencies are not more pronounced than in other patients. It can be concluded, therefore, that the deficiencies of agrammatic patients are of a structural character rather than due to memory span loss.     

Quantitative analysis of aphasic sentence production: further development and new data

The narrative production of patients with Broca's aphasia and age-and education-matched control subjects was analyzed using the Quantitative Production Analysis (Saffran et al., 1989), a procedure designed to provide measures of morphological and structural characteristics of aphasic production. In addition to providing data for a larger number of subjects than in the original study, we provide data on interrater and test-retest reliability. The data were also submitted to factor and cluster analyses. Two factors characterized the data and the cluster analysis yielded four sets of patients who performed differently on these factors. In particular, there is evidence that agrammatic patients can differ in their production of free and bound grammatical morphemes, substantiating earlier claims in the literature.     

Familial Handedness and Access to Words, Meaning, and Syntax during Sentence Comprehension

We compared right-handed familial dextral (FS-) and familial sinistral (FS+) participants who were aged either 10-13 years (children) or 18-23 years (adults). In word probe and associative probe tasks, FS+ adults responded faster than all other groups and FS+ children responded more slowly than all other groups. In the word probe task, only the FS- adults showed a significant effect of the serial position of the target word. We interpret these differences to support an analysis-by-synthesis model of comprehension in which individuals who differ in familial handedness and age emphasize different linguistic representations during comprehension. In general, FS+ individuals focus on words and meaning, while FS- individuals focus on syntactic representations. In FS+ individuals, age-related experiences with language produce a shift in responding from compositional meaning to words and their associations. In FS- individuals, age-related experiences with language produce a shift toward responding based more on detailed syntactic representations, including the serial order of words and possibly the structural roles of clauses.     

自我解释与工作记忆对汉语阅读理解的影响

采用组间实验设计,以汉语科技说明文为阅读材料,探讨自我解释与工作记忆对汉语阅读理解的影响以及工作记忆对自我解释活动本身的影响.结果表明:(1)自我解释活动促进了被试对文本的理解.(2)较高的言语工作记忆容量对汉语阅读理解有促进作用.(3)高工作记忆容量组比低工作记忆容量组不仅在阅读过程中产生了更多数量的自我解释,而且还更多地使用衔接和推理的解释模式.     

Nature of the working memory deficit in fragile-X syndrome

Working memory performance in a group of young Fragile X males with FMR-1 full mutation was compared to a learning disabled comparison group comprising Down's syndrome males and two control groups of mainstream schoolchildren. Performance was assessed on a battery of tasks tapping the three components of working memory-phonological loop, visual-spatial sketch pad, and the central executive. The results indicated that the Fragile X group displayed a general impairment on working memory tasks that cannot be attributed to a single working memory component per se. Instead, the results suggest that Fragile X males have a working memory deficit that may be attributed to how much attentional resource a specific task requires and their overall available executive capacity, irrespective of the working memory subsystem.     

Comprehension of reversible relative clauses in specifically language impaired and normally developing Greek children

This paper aims to investigate the syntactic comprehension of reversible relative clauses in a group of eight Greek children with specific language impairment (SLI) and two control groups of normally developing children matched on chronological and language age, respectively. An experiment using an acting out procedure was undertaken. Group analysis revealed that SLI children's performance is qualitatively different than that of both control groups. Interpreting the data, processes involved in syntactic comprehension are taken into consideration. It is claimed that processing demands impede SLI children's performance due to a deficit in their competence grammar.     

Reperfusion of Specific Brain Regions by Raising Blood Pressure Restores Selective Language Functions in Subacute Stroke

We report a series of six single subject studies examining the effects of pharmacological blood pressure elevation on regional brain perfusion and language function. Previous reports indicate that hypoperfusion of specific brain regions, as delineated by magnetic resonance perfusion weighted imaging (PWI), is associated with disruption of selective lexical functions. On this basis, we hypothesized that reperfusion of the same regions, in the absence of infarct in that region, would restore the associated lexical function. We present five patients with impaired lexical-semantics associated with poor perfusion, but not infarction, of Brodmann's area 22 (BA 22), and one patient with impaired lexical-semantics and a superimposed deficit in retrieving the phonological representations of words, associated with poor perfusion Brodmann's area 37 (BA 37) as well as BA 22. Each patient was treated with induced blood pressure elevation to increase perfusion of the ischemic and dysfunctional tissue. Daily testing of naming and comprehension, with stimulus sets matched for frequency, familiarity, and length, showed improved lexical-semantics in the patients who showed reperfusion of BA 22 and improved oral naming (but not lexical-semantics) in the patient who showed reperfusion of BA 37. These cases illustrate that loss of function with hypoperfusion of a circumscribed area of the brain, and recovery of the same function with improved perfusion of that brain region, can reveal brain/language relationships prior to reorganization after brain injury.     

Language and cognition-Kurt Goldstein's theory of semantics

Kurt Goldstein is regarded as one of the major proponents of the holistic movement at the beginning of the 20th century. He rejected the strong localization hypothesis in the field of aphasiology and attempted to link language disturbances to an underlying general intellectual impairment. Goldstein's criticism was based on his subtle symptomatology, his organismic biology, and his philosophical reflections. In his concept of abstract attitude Goldstein searched for a general psychological function that might explain a variety of aphasic symptoms. Abstract attitude bridges the gap between cognitive and linguistic structures. According to Goldstein, it is the basis for words to have a meaning, to be employed in a categorical sense. Since amnesic aphasics are confined to a concrete attitude, their words have lost their representational function. Although Goldstein's concept of abstract attitude is no longer used in scientific discourse, it is analyzed for its heuristic value. It led Goldstein to questions about the relation between cognition and language and to fragments of a semantic theory.     

Effects of domain knowledge,working memory capacity,and age on cognitive performance: an investigation of the knowledge-is-power hypothesis

Domain knowledge facilitates performance in many cognitive tasks. However, very little is known about the interplay between domain knowledge and factors that are believed to reflect general, and relatively stable, characteristics of the individual. The primary goal of this study was to investigate the interplay between domain knowledge and one such factor: working memory capacity. Adults from wide ranges of working memory capacity, age, and knowledge about the game of baseball listened to, and then answered questions about, simulated radio broadcasts of baseball games. There was a strong facilitative effect of preexisting knowledge of baseball on memory performance, particularly for information judged to be directly relevant to the baseball games. However, there was a positive effect of working memory capacity on memory performance as well, and there was no indication that domain knowledge attenuated this effect. That is, working memory capacity contributed to memory performance even at high levels of domain knowledge. Similarly, there was no evidence that domain knowledge attenuated age-related differences (favoring young adults) in memory performance. We discuss implications of the results for understanding proficiency in cognitive domains from an individual-differences perspective.     

Lapses of intention and performance variability reveal age-related increases in fluctuations of executive control

We examine the hypothesis that the efficiency of executive control processes is less stable over time in older than younger adults. An age-related decrease in the efficiency of executive control should result in an increase in performance variability in task conditions requiring the recruitment of executive control processes and not in task conditions requiring minimal involvement of executive control. Performance variability was similar for younger and older adults in task conditions requiring minimal executive control and greater for older than younger adults in task conditions requiring executive control. These and other data are consistent with the proposal that aging is associated with a decrease in the stability of executive control over time.     

心智游移、工作记忆对初中生阅读理解的影响

心智游移（mind wandering,MW）是一种特殊的注意分散状态,是个体内部自发的一种非自主内源性意识体验。选取101名初一学生被试,采用心智游移频率问卷和SART测验研究初中生的心智游移特质和状态,并分别考察两种角度中的心智游移、工作记忆对初中生阅读理解的影响,结果表明：（1）初中生的心智游移相对较低;（2）心智游移影响初中生的散文阅读;（3）工作记忆影响初中生的散文阅读,且心智游移在其中起调节作用。     

汉、英工作记忆的加工和储存对中学生英语阅读理解的影响

本研究采用"视空间和言语交替"任务范式分离言语工作记忆的加工和储存两个成分,分别探讨了英语工作记忆的加工和储存成分对我国中学生英语阅读理解的作用及其途径,以及汉语工作记忆的加工和储存成分对中学生英语阅读理解是否具有跨语言影响。98名初中二年级学生完成了一般认知能力、英语阅读理解、汉语和英语工作记忆任务。结果表明:(1)英语工作记忆的加工和储存成分对英语阅读理解均有显著的独立预测作用;(2)英语工作记忆的储存成分对英语阅读理解的作用部分是由加工成分引起的;(3)汉语工作记忆的加工成分对英语阅读理解没有显著的直接预测作用,但却以英语工作记忆的加工成分为中介间接作用于英语阅读理解;汉语工作记忆的储存成分对英语阅读理解没有显著的预测作用。可见,言语工作记忆是一个多成分系统,加工和储存两个成分是相对分离的,并且它们具有不同的跨语言特性,加工存在跨语言一般性,而储存则具有语言特异性。     

Neural correlates of successful and unsuccessful verbal memory encoding

Recent neuroimaging studies suggest that episodic memory encoding involves a network of neocortical structures which may act interdependently with medial temporal lobe (mTL) structures to promote the formation of durable memories, and that activation in certain structures is modulated according to task performance. Functional magnetic resonance imaging (fMRI) was used to determine the neural structures recruited during a verbal episodic encoding task and to examine the relationship between activation during encoding and subsequent recognition memory performance across subjects. Our results show performance-correlated activation during encoding both in neocortical and medial temporal structures. Neocortical activations associated with later successful and unsuccessful recognition memory were found to differ not only in magnitude, but also in hemispheric laterality. These performance-related hemispheric effects, which have not been previously reported, may correspond to between-subject differences in encoding strategy.     

Phonology: A Review and Proposals from a Connectionist Perspective

A parallel distributed processing (PDP) model of phonological processing is developed, including components to support repetition, auditory processing, comprehension, and language production. From the performance of the PDP reading model of Plaut, McClelland, Seidenberg, and Patterson (1996), it is inferred that the acoustic-articulatory motor pattern associator that supports repetition provides the basis for phonological sequence knowledge. From the observation that many patients make phonemic paraphasic errors in language production, as in repetition, it is argued that there must be a direct link between distributed concept representations (lexical semantic knowledge) and this network representation of sequence knowledge. In this way, both lexical semantic and phonotactic constraints are brought to bear on language production. The literature on phonological function in normal subjects (slip-of-the-tongue corpora) and in patients with aphasia is critically reviewed from this perspective. The relationship between acoustic and articulatory motor representations in the process of phonetic perception is considered. Repetition and reproduction conduction aphasia are reviewed in detail and extended consideration is given to the representation of auditory verbal short-term memory in the model. Finally, the PDP model is reconciled with information processing models of phonological processing, including that of Lichtheim, and with current knowledge of the anatomic localization of phonological processing. Although no simulations of the model were run, a number of simulation studies are proposed.     

Controversies about CP: a comparison of language acquisition and language impairments in Broca's aphasia

In both language acquisition research and the study of language impairments in Broca's aphasia there is an ongoing debate whether or not phrase-structure representations contain the Complementizer Phrase (CP) layer. To shed some light on this debate, I will provide data on German child language and on German agrammatic Broca's aphasia. Analyses of subordinate clauses, wh-questions, and verb placement indicate that early child grammars do not generate the CP layer yet, whereas the ability to project the CP layer is retained in agrammatism.     

Ratings of emotion in laterally presented faces: sex and handedness effects

Sixteen right-handed participants (8 male and 8 female students) and 16 left-handed participants (8 male and 8 female students) were presented with cartoon faces expressing emotions ranging from extremely positive to extremely negative. A forced-choice paradigm was used in which the participants were asked to rate the faces as either positive or negative. Compared to men, women rated faces more positively, especially in response to right visual field presentations. Women rated neutral and mildly positive faces more positively in the right than in the left visual field, whereas men rated these faces consistently across visual fields. Handedness did not affect the ratings of emotion. The data suggest a positive emotional bias of the left hemisphere in women.     

The Effects of Scrambling on Spanish and Korean Agrammatic Interpretation: Why Linear Models Fail and Structural Models Survive

Several models of comprehension deficits in agrammatic aphasia rely heavily on linear considerations in the assignment of thematic roles to structural positions (e.g., the Trace-Deletion Hypothesis, the Mapping Hypothesis, and the Argument-Linking Hypothesis). These accounts predict that constructions in languages with rules that affect syntactic structure but preserve relative linear order should be unimpaired. Other models [e.g., the Double-Dependency Hypothesis, (DDH)] do not resort to linearity but are purely structural in conception and therefore should be immune to word-order effects. We tested linear and nonlinear accounts with scrambling structures in Korean and topicalization structures in Spanish. The results are very clear. The (nonlinear) DDH is entirely compatible with the evidence, but the linear accounts are not.     

Dichotic Perception of Mandarin Tones by Chinese and American Listeners

The dichotic perception of Mandarin tones by native and nonnative listeners was examined in order to investigate the lateralization of lexical tone. Twenty American listeners with no tone language background and 20 Chinese listeners were asked to identify dichotically presented tone pairs by identifying which tone they heard in each ear. For the Chinese listeners, 57% of the total errors occurred via the left ear, indicating a significant right ear advantage. However, the American listeners revealed no significant ear preference, with 48% of the errors attributable to the left ear. These results indicated that Mandarin tones are predominantly processed in the left hemisphere by native Mandarin speakers, whereas they are bilaterally processed by American English speakers with no prior tone experience. The results also suggest that the left hemisphere superiority for native Mandarin tone processing is similar to native processing of other tone languages.     

Functional heterogeneity of inferior frontal gyrus is shaped by linguistic experience

A crosslinguistic, positron emission tomography (PET) study was conducted to determine the influence of linguistic experience on the perception of segmental (consonants and vowels) and suprasegmental (tones) information. Chinese and English subjects (10 per group) were presented binaurally with lists consisting of five Chinese monosyllabic morphemes (speech) or low-pass-filtered versions of the same stimuli (nonspeech). The first and last items were targeted for comparison; the time interval between target tones was filled with irrelevant distractor tones. A speeded-response, selective attention paradigm required subjects to make discrimination judgments of the target items while ignoring intervening distractor tones. PET scans were acquired for five tasks presented twice: one passive listening to pitch (nonspeech) and four active (speech = consonant, vowel, and tone; nonspeech = pitch). Significant regional changes in blood flow were identified from comparisons of group-averaged images of active tasks relative to passive listening. Chinese subjects show increased activity in left premotor cortex, pars opercularis, and pars triangularis across the four tasks. English subjects, on the other hand, show increased activity in left inferior frontal gyrus regions only in the vowel task and in right inferior frontal gyrus regions in the pitch task. Findings suggest that functional circuits engaged in speech perception depend on linguistic experience. All linguistic information signaled by prosodic cues engages left-hemisphere mechanisms. Storage and executive processes of working memory that are implicated in phonological processing are mediated in discrete regions of the left frontal lobe.