Syntactic event-related potential components in 24-month-olds' sentence comprehension

The processing of syntactic violations in adults is associated with a biphasic event-related potential pattern consisting of an early left anterior negativity and a late positivity called the P600. While the early left anterior negativity reflects highly automatic sentence parsing, the P600 reflects processes of syntactic reanalyses or repair. The present study investigated the processing of phrase structure information in 24-month-old German-speaking children. During the experimental session, the children listened to short active sentences that were either syntactically correct or contained a phrase structure violation. The event-related potential s of the children displayed a late positivity in response to phrase structure violations. Our findings indicate that even children at this early age are sensitive to syntactic errors in the form of phrase structure violations.     

Summation of semantic priming and complex sentence comprehension in Parkinson's disease

Research has suggested that the integrity of semantic processing may be compromised in Parkinson's disease (PD), which may account for difficulties in complex sentence comprehension. In order to investigate the time course and integrity of semantic activation in PD, 20 patients with PD and 23 healthy controls performed a lexical decision task based on the multi-priming paradigm. Semantic priming effects were measured across stimulus onset asynchronies of 250 ms, 600 ms, and 1200 ms. Further, PD participants performed an auditory comprehension task. The results revealed significantly different patterns of semantic priming for the PD group at the 250-ms and 1200-ms SOAs. In addition, a delayed time course of semantic activation was evident for PD patients with poor comprehension of complex sentences. These results provide further support to suggest that both automatic and controlled aspects of semantic activation may be compromised in PD. Furthermore, the results also suggest that some sentence comprehension deficits in PD may be related to a reduction in information processing speed.     

The relative timing of syntactic and semantic processes in sentence comprehension

The functional primacy of syntactic over semantic processes was put to test in an auditory event-related brain potentials study using sentences in which the final words were semantically and/or syntactically incongruent with the prior context. Crucially, these words encoded the syntactically relevant word category information in the suffix, available only after the word stem which carried the semantic information. Semantic violations elicited an N400 and syntactic violations a biphasic LAN-P600 pattern. Words that were semantically and syntactically incongruent with the context evoked a biphasic LAN-P600 ERP pattern, but no N400. The similarity of the ERP pattern for the pure syntactic and the double violation condition provides strong evidence for a functional primacy of initial syntactic over lexical-semantic processes.     

Short-term semantic retention during on-line sentence comprehension. Brain potential evidence from filler-gap constructions

In filler-gap sentences, a phrase ('filler') is separated by intervening words from a subsequent phrase ('gap') with which it is integrated. The filler-gap interval provides a useful model for the study of short-term retention processes during sentence comprehension. Kluender and Kutas [J. Cogn. Neurosci. 5 (1993) 29] used event-related brain potentials (ERPs) to show that a filler phrase places a demand on short-term retention processes in the filler-gap interval, but left the processing level at which this demand arises unspecified. Here we use ERPs to address the issue of whether the filler places a demand on the semantic component of short-term retention processes in the filler-gap interval. Participants read filler-gap sentences, which began with a filler phrase and, in the filler-gap interval, contained a subject and object that were either semantically related or unrelated. There was also a control condition in which the filler phrase was absent (i.e. less memory demand). The main result was that during the filler-gap interval, bilateral posterior electrodes displayed a larger positivity for unrelated than related words. Moreover, during the same interval, posterior electrodes displayed a larger positivity for filler-gap sentences than for control sentences. In the control condition (non-filler gap sentences), manipulation of semantic relatedness did not produce differences in ERP activity. Our results suggest that a filler phrase places a demand on the semantic component of verbal working memory during on-line sentence comprehension.     

CASE STUDY Syntactic comprehension of reversible sentences in semantic dementia

Background: A patient with semantic dementia had difficulty comprehending semantically reversible passive sentences in the Test for the Reception of Grammar (TROG). Investigations of patients with semantic dementia have typically focused on the lexical and semantic components of language. Syntactic abilities have received less attention, presumably because these are reported to be preserved until later stages of the disease. Aim: To localise the possible functional sources of deficient comprehension of passives in a Dutch man (EGY) with semantic dementia. Methods & Procedures: Dutch written sentence picture–matching tasks were used to investigate whether EGY assigned the thematic role of agent on the basis of word order, the presence of auxiliary plus inflected verb morphology, the by phrase, the presence of a locative preposition (against and after), or the lexical‐semantic specifications of the verbs push and chase. Outcomes & Results: EGY was able to understand reversible active and truncated passive sentences. He was impaired when comprehension depended on understanding the agentive role of the by phrase, although his performance improved when a locative preposition was available to highlight the theme of the action. Conclusions: Intact performance on reversible active sentences indicated spared ability to process canonical word order. EGY's ability to understand truncated passives showed comprehension of the auxiliary and inflected verb, perhaps resulting in a conceptual representation of the passive as an adjectival construction (e.g., the cow is pushed = the pushed cow). EGY's deficit in comprehending full passive sentences is explained as a failure to process the syntactic and lexical information in the agentive by preposition. In semantic dementia, the division between lexicon and grammar may be more apparent than real.     

Segregating early physical and syntactic processes in auditory sentence comprehension

Auditory language comprehension involves physical as well as syntactic processing. The present study examined whether early physical and syntactic processes in spoken sentence comprehension can be segregated using event-related brain potentials (ERPs). In the physical manipulation condition, the terminal word of the sentence was presented either from the same or from a different location to the preceding sentence fragment. In the syntactic manipulation condition, the terminal word was either a syntactically correct continuation of the preceding sentence fragment or violated syntactic constraints. These two factors were completely crossed. Physical deviances elicited the mismatch negativity (MMN) and syntactic deviances the early syntax-related negativity, both deviance-related components of the ERP. Sentences which violated physical as well as syntactic constraints elicited a negativity which was larger than that elicited by only a physical or only a syntactic deviance. The elicitation of the MMN in connected speech demonstrates that this component can be used as a probe for auditory change-detection even in ecologically highly valid situations. The increase of deviance-related effects with double deviants suggests that the early physical and syntactic processing systems act, to a high degree, in parallel and independently of each other.     

Lexical access rate of closed-class elements during auditory sentence comprehension in adults with aphasia

Background: One hypothesis regarding the underlying impairment in agrammatic comprehension suggests that individuals with this disorder suffer from a reduction in lexical activation of closed-class words and therefore cannot appropriately construct a syntactic frame on which lexical semantic information can be applied (Friederici, 1988). Aims: Given the temporally based hypothesis, this investigation examined the effects of increased inter-word intervals (IWI) following closed-class words on auditory comprehension of various sentence types by individuals with agrammatic comprehension. It was hypothesised that providing a longer temporal window for access and processing of closedclass words would improve sentence structure comprehension. Methods & Procedures: Twelve adults with aphasia participated in an agent identification task given varying auditory sentence stimuli. Six sentence types and six IWI durations served as independent variable while accuracy and response times were measured. Outcomes & Results: Results indicated that auditory sentence comprehension performance improves when IWIs are increased. However, differences exist among individuals in response to specific IWI durations. Conclusions: Implications of delayed access rates of closed-class words in agrammatic comprehension are discussed.     

失语患者的句子理解实验研究

目的分析失语患者句子语义加工特点,为言语康复训练提供依据。方法将研究对象分为2组,即20例失语患者(失语组)和20例无失语患者(对照组);实验1考察句子语义结构判断,实验2为不同句法难度句子的语义加工,实验3是复句的逻辑语义判断。结果实验组对语义结构加工明显不及对照组;对于句法难度不同的句子语义加工,实验组与对照组对于不同类型句子判断的难度顺序一致,但判断能力上有一定的差异;实验组对于关联词语与肢命题的逻辑语义关系的分析能力明显不及对照组。结论失语患者句子语义加工特点不同,应作为针对性制定康复计划的客观依据。     

Interaction between phonological and semantic factors in auditory comprehension

This study compared Wernicke's and Broca's aphasic patients as to the influence of phonological vs semantic factors in their ability to make phonemic discriminations. Eight subjects of each diagnostic type participated in three experiments in which semantic processing played an increasing role. Experiment I was an auditory-auditory same-different match, Experiment II was an auditory-visual same-different match and Experiment III was an auditory vs visual multiple choice, introducing the possibility of either semantically or phonologically based errors. Wernicke's aphasics were more impaired than Broca's at all levels, but their performance was disproportionately impaired as semantic mediation was introduced. Semantically based errors outnumbered phonologically based errors in Experiment III, which showed that just as semantic processing demand increases the risk of phonological error, so does phonological difficulty increase the risk of semantic error.     

Instantiation of semantic categories in sentence comprehension by Alzheimer patients.

This study examined whether Alzheimer patients can make elaborative inferences based on the semantic context provided by a sentence. More specifically, if presented with the name of a category in a sentence do they, like normals, infer (instantiate) the particular member of that category most appropriate to the meaning of the sentence (e.g., if a sentence mentions a container of juice, do they infer it is a bottle). Patients were presented with a sentence containing the name of a concrete category. The sense of the sentence was consistent with a low-dominant member of that category. Patients were then shown drawings of four members of that category and asked to select the one appropriate to the sentence. They were later asked to name the drawings. If semantic information is degraded in Alzheimer patients for those objects Alzheimer patients cannot name (as has been claimed), then AD patients should be unable to carry out the type of elaborative semantic inference required to instantiate. Results showed that Alzheimer patients were highly accurate at instantiating even objects they could not name. This is consistent with a relative preservation of semantic knowledge about concrete objects in Alzheimer patients.     

Interplay between syntax and semantics during sentence comprehension: ERP effects of combining syntactic and semantic violations

This study investigated the effects of combined semantic and syntactic violations in relation to the effects of single semantic and single syntactic violations on language-related event-related brain potential (ERP) effects (N400 and P600/SPS). Syntactic violations consisted of a mismatch in grammatical gender or number features of the definite article and the noun in sentence-internal or sentence-final noun phrases (NPs). Semantic violations consisted of semantically implausible adjective-noun combinations in the same NPs. Combined syntactic and semantic violations were a summation of these two respective violation types. ERPs were recorded while subjects read the sentences with the different types of violations and the correct control sentences. ERP effects were computed relative to ERPs elicited by the sentence-internal or sentence-final nouns. The size of the N400 effect to the semantic violation was increased by an additional syntactic violation (the syntactic boost). In contrast, the size of the P600/SPS to the syntactic violation was not affected by an additional semantic violation. This suggests that in the absence of syntactic ambiguity, the assignment of syntactic structure is independent of semantic context. However, semantic integration is influenced by syntactic processing. In the sentence-final position, additional global processing consequences were obtained as a result of earlier violations in the sentence. The resulting increase in the N400 amplitude to sentence-final words was independent of the nature of the violation. A speeded anomaly detection task revealed that it takes substantially longer to detect semantic than syntactic anomalies. These results are discussed in relation to the latency and processing characteristics of the N400 and P600/SPS effects. Overall, the results reveal an asymmetry in the interplay between syntax and semantics during on-line sentence comprehension.     

失语患者听理解中的特殊范畴语义障碍

目的：探讨失语患者听理解中特殊范畴语义障碍的特点。方法：（1）用汉语失语检查法（ABC）检查42例卒中后失语患者，其中，Broca失语（BA）8例，Wernicke失语9WA）5例，传导性失语（CA）11例，经皮质运动性失语（TCM）8例，经皮质感觉性失语（TCS）7例，命名性失语（AA）3例；（2）分别统计各型失语患者ABC中听辨认9项的得分，并用SPSS软件处理数据。结果：（1）BA、TCM和AA患者听辨认9项间差异无显著性意义（P＞0．05）。（2）WA、CA、TCS患者对9个项目的听辨认存在不同程度困难；物品和动作听理解障碍的程度较轻，而颜色和（或）身体部位的听理解障碍较重。差异有显著意义的（P＜0．05）是：WA患者在物品（M＝4分）、物品图（M＝6分）、动作图（M＝4分）与颜色（M＝0）分、家具（M＝0分）及身体部位（高、低频和左／右）（M＝2，0，0分）间，几何图（M＝2分）与物品图及身体部位（低频）间；CA患者在物品（M＝10分）、物品图（M＝10分）、动作图（M＝10分）与身体部位（高、低频和左／右）（M＝9，8，4分）间，几何图（M＝9分）与物品图间，颜色（M＝10分）、家具（M＝10分）与身体部位（低频）间；TCS患者在物品（M＝10分）与家具（M＝5分）和身体部位（低频）（M＝6分）间，动作图（M＝10分）、家具和身体部位（低频）间。结论：（1）失语患者听理解中特殊范畴语义障碍主要见于有明显听理解障碍者，（2）不同型失语患者的听辨认中有相似的特殊范畴语义障碍。     

Processing consequences of superfluous and missing prosodic breaks in auditory sentence comprehension

This ERP study investigates whether a superfluous prosodic break (i.e., a prosodic break that does not coincide with a syntactic break) has more severe processing consequences during auditory sentence comprehension than a missing prosodic break (i.e., the absence of a prosodic break at the position of a syntactic break). Participants listened to temporarily ambiguous sentences involving a prosody–syntax match or mismatch. The disambiguation of these sentences was always lexical in nature in the present experiment. This contrasts with a related study by Pauker, Itzhak, Baum, and Steinhauer (2011), where the disambiguation was of a lexical type for missing PBs and of a prosodic type for superfluous PBs. Our results converge with those of Pauker et al. (2011): superfluous prosodic breaks lead to more severe processing problems than missing prosodic breaks. Importantly, the present results extend those of Pauker et al. (2011) showing that this holds when the disambiguation is always lexical in nature. Furthermore, our results show that the way listeners use prosody can change over the course of the experiment which bears consequences for future studies.     

Oscillatory brain activity in vegetative and minimally conscious state during a sentence comprehension task

Patients with altered states of consciousness continue to constitute a major challenge in terms of clinical assessment, treatment and daily management. Furthermore, the exploration of brain function in severely brain-damaged patients represents a unique lesional approach to the scientific study of consciousness. Electroencephalography is one means of identifying covert behaviour in the absence of motor activity in these critically ill patients. Here we focus on a language processing task which assesses whether vegetative (n=10) and minimally conscious state patients (n=4) (vs control subjects, n=14) understand semantic information on a sentence level ("The opposite of black is... white/yellow/nice"). Results indicate that only MCS but not VS patients show differential processing of unrelated ("nice") and antonym ("white") words in the form of parietal alpha (10-12Hz) event-related synchronization and desynchronization (ERS/ERD), respectively. Controls show a more typical pattern, characterized by alpha ERD in response to unrelated words and alpha ERS in response to antonyms.     

An event-related brain potential study of sentence comprehension in preschoolers: semantic and morphosyntactic processing

The goal of this study was to investigate the distinctiveness and the relative time course of the event-related brain potentials (ERP) elicited by syntactically and semantically anomalous words within sentences in 36- and 48-month-old children. ERPs were recorded while children listened to semantically anomalous (i.e., My uncle will blow the movie*), syntactically anomalous (i.e., My uncle will watching the movie*) and control sentences (i.e., My uncle will watch the movie). Semantic violations elicited a negative slow wave with different peaks at 400, 600 and 800 ms in both age groups, whereas the morphosyntactic violations elicited two positive shifts: the first starting at 200 ms with a frontal distribution over the scalp and the second starting at 600 ms and peaking around 800 ms with a broad distribution across the scalp in 36-month-olds and anteriorly distributed for 48-month-olds. These results show that preschoolers display different ERP patterns to syntactic and to semantic violations within sentences. It is possible that the ERP effects here reported are analogous to those elicited in adults by the same type of stimuli, although differences in topography are evident.     

Measuring processing load during sentence comprehension: Visuomotor tracking

This investigation examined processing load during aspects of sentence comprehension in non-brain-damaged subjects. Our goals were to begin the process of quantifying the loads associated with on-line and off-line aspects of sentence processing and to evaluate the utility of visuomotor tracking as an index of the resource demand associated with elements of sentence comprehension. Subjects were required to track an unpredictable visual target with their forefinger while listening to sentences and answering Yes-No comprehension questions. In general, tracking performance declined during the off-line task of responding to questions compared to the on-line task of listening to sentences and questions. Performance was also poorer during the beginning and end of the sentence compared to the middle of the sentence. Results are discussed in relation to resource theories of normal and aphasic sentence comprehension.     

The semantic deficit in aphasia: the relationship between semantic errors in auditory comprehension and picture naming

Thirty aphasic subjects were asked to point to pictures on auditory command both when the distractors came from the same semantic category as the target and when the distractors were unrelated to the target picture. The aphasics made significantly more semantic errors than non-aphasic brain-damaged controls; the incidence of semantic comprehension errors was unrelated to aphasic diagnostic groups but was related to the overall severity of aphasia. The subjects were subsequently asked to name the pictures from the comprehension task; pictures that had elicited semantic errors in comprehension were no less likely to be named than those that had not, but the incidence of semantic errors in comprehension correlated significantly with their incidence in naming. The implications of a semantic deficit common to both auditory comprehension and naming that is not specific to particular lexical items is discussed in relation to a number of information processing models of the lexicon.     

Role of anterior temporal cortex in auditory sentence comprehension: an fMRI study.

Recent neuropsychological and functional imaging evidence has suggested a role for anterior temporal cortex in sentence-level comprehension. We explored this hypothesis using event-related fMRI. Subjects were scanned while they listened to either a sequence of environmental sounds describing an event or a corresponding sentence matched as closely as possible in meaning. Both types of stimuli required subjects to integrate auditory information over time to derive a similar meaning, but differ in the processing mechanisms leading to the integration of that information, with speech input requiring syntactic mechanisms and environmental sounds utilizing non-linguistic mechanisms. Consistent with recent claims, sentences produced greater activation than environmental sounds in anterior superior temporal lobe bilaterally. A similar speech > sound activation pattern was noted also in posterior superior temporal regions in the left. Envirornmental sounds produced greater activation than sentences in right inferior frontal gyrus. The results provide support for the view that anterior temporal cortex plays an important role in sentence-level comprehension.     

Processing the universal quantifier during sentence comprehension: ERP evidence

This study investigates the temporal neural dynamics of processing the Chinese universal quantifier dou during Chinese sentence comprehension using the event-related potential (ERP) technique. Universal quantifier violations were created when the universal quantifier dou (all, every) was misplaced either after a singular object noun phrase (NP) in a Subject–Object–Verb (SOV) sentence (Experiments 1 and 3) or after a singular subject NP in a SVO sentence (Experiment 2). Participants were asked to make semantic plausibility judgment (Experiments 1 and 2) or to comprehend sentences real time followed by a sentence recognition test at the end of the experiment (Experiment 3). Experiment 1 found that quantifier violations elicited a sustained positivity from 400 to 1100 ms post-onset of the quantifier and a sustained negativity from 300 to 800 ms post-onset of the following verb. Experiment 2 varied the distance between dou and the following verb by the presence or absence of an adverb between them. Again, the sustained positivity was observed on the mismatching quantifier; in addition, a sustained negativity was observed on the word immediately following the quantifier, regardless of whether this word was a verb or adverb. Experiment 3 used the same stimuli as Experiment 1 but with a different task. The quantifier violation elicited anteriorly distributed negativities over different time intervals post-onset of the quantifier. The sustained positivity is interpreted as being associated with an integration process that links the universal quantifier with the preceding entity. The sustained negativity is attributed to a second-pass process to reinterpret the sentence. Other functional interpretations of the ERP components were discussed and ruled out.