First-pass versus second-pass parsing processes in a Wernicke's and a Broca's aphasic: electrophysiological evidence for a double dissociation

The present paper is a first attempt to integrate the classical brain lesion behavioral impairment approach of functional neuroanatomy and the electrophysiological brain mapping approach in the domain of syntactic processing. In a group of normal age-matched controls we identified three electrophysiological components previously observed in correlation with language comprehension processes: an early left anterior negativity normally seen in correlation with syntactic first-pass parsing processes (ELAN), a centroparietal negativity seen in correlation with processes of lexical-semantic integration (N400), and a late centroparietal positivity observed in correlation with secondary syntactic processes of reanalysis and repair (P600). The early left anterior negativity was absent in a patient with an extended lesion in the anterior part of the left hemisphere sparing the temporal lobe, although the late centroparietal positivity and the centroparietal N400 were present. In a patient with a left temporal-parietal lesion the early left anterior negativity was found to be present, whereas the N400 component was absent. These findings suggest that first-pass parsing and secondary processes are subserved by distinct brain systems.     

Ambiguity in the Brain: What Brain Imaging Reveals About the Processing of Syntactically Ambiguous Sentences.

Two fMRI studies investigated the time course and amplitude of brain activity in language-related areas during the processing of syntactically ambiguous sentences. In Experiment 1, higher levels of activation were found during the reading of unpreferred syntactic structures as well as more complex structures. In Experiments 2A and 2B higher levels of brain activation were found for ambiguous sentences compared with unambiguous sentences matched for syntactic complexity, even when the ambiguities were resolved in favor of the preferred syntactic construction (despite the absence of this difference in previous reading time results). Although results can be reconciled with either serial or parallel models of sentence parsing, they arguably fit better into the parallel framework. Serial models can admittedly be made consistent but only by including a parallel component. The fMRI data indicate the involvement of a parallel component in syntactic parsing that might be either a selection mechanism or a construction of multiple parses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Making sense of sentences in schizophrenia: Electrophysiological evidence for abnormal interactions between semantic and syntactic processing.

Event-related potentials to critical verbs were measured as patients with schizophrenia and healthy controls read sentences word by word. Relative to their preceding context, critical verbs were (a) congruous, (b) incongruous and semantically unrelated to individual preceding words (pragmatic-semantic violations), (c) incongruous but semantically related to individual preceding words (animacy-semantic violations), or (d) syntactically anomalous. The N400 was modulated normally in patients, suggesting that semantic integration between individual words within sentences was normal in schizophrenia. The amplitude of the P600 to both syntactic and animacy-semantic violations was reduced in patients relative to controls. The authors suggest that, in schizophrenia, an abnormality in combining semantic and syntactic information online to build up propositional meaning leaves sentence processing to be primarily driven by semantic relationships between individual words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contextual information modulates initial processes of syntactic integration: The role of inter- versus intrasentential predictions.

The authors demonstrate that intersentential context may influence syntactic integration processes during online sentence comprehension, although this influence appears to be restricted to cases in which a contextual requirement must be fulfilled. By applying event-related brain potentials to the processing of clause-medial word order variations in German, the authors show that the local processing difficulty (a negativity from 300 to 450 ms) observed for object-initial sentences in a neutral context is also obtained in a (behaviorally) facilitating context in which the object is contextually given. By contrast, the processing pattern for a focused (questioned) initial object does not differ from that for a focused subject: both elicit a parietal positivity (280-480 ms) postonset of the focused phrase. The authors interpret this early positivity as a general marker of focus integration, a process that appears to briefly supersede sentence-internal requirements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical and sentence context effects in word recognition.

Three experiments examined lexical and sentence-level contributions to contextual facilitation effects in word recognition. Subjects named target words preceded by normal or scrambled sentence contexts that contained lexical associates of the target. In Experiment 1, normal sentences showed facilitation for related targets and inhibition for unrelated targets. Experiment 2 eliminated syntactically anomalous targets among unrelated items and showed only facilitation for related targets. In neither experiment was there any effect of relatedness for scrambled stimuli. Experiment 3 included syntactically normal but semantically anomalous sentences to test whether the failure of scrambled sentences to show priming was due to their syntactic incoherence. Normal sentences again showed contextual facilitation, but neither scrambled nor anomalous sentences showed such effects. The results indicate that there are sentence-context effects that do not arise solely from intralexical spreading activation and suggest that context facilitates the identification of a lexical candidate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensitivity to syntactic and semantic cues in good and poor comprehenders.

Fourth graders ( N = 48) who were equivalent on word recognition skills, but differed in comprehension ability, read sentences manipulated at the verb position to determine whether sensitivity to syntactic and semantic cues differs between good and poor comprehenders. Data in the form of oral reading errors at the verb position support the hypothesis that poor comprehenders are not affected by the disruptive effect of syntactic and semantic violations, while good comprehenders exhibit an increasing number of errors across semantic and syntactic/semantic violations. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantics does not need a processing license from syntax in reading Chinese.

Two event-related brain potential experiments were conducted to investigate whether there is a functional primacy of syntactic structure building over semantic processes during Chinese sentence reading. In both experiments, we found that semantic interpretation proceeded despite the impossibility of a well-formed syntactic analysis. In Experiment 1, we found an N400 difference between combined syntactic category and semantic violations and single syntactic violations. This finding is inconsistent with earlier German and French studies (e.g., Friederici, Gunter, Hahne, & Mauth, 2004; Friederici, Steinhauer, & Frisch, 1999; Hahne & Friederici, 2002) showing that semantic integration does not proceed for words of the wrong syntactic category. In Experiment 2, we used a design that was very similar to that used in earlier German and French studies, but semantic violations still evoked an N400, irrespective of a simultaneous syntactic category violation. We argue against processing models that do not allow for semantic integration of a word unless it can be grammatically attached to the developing phrase structure tree. Rather, language experience may modulate the mode of interplay between syntax and semantics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syntactic comprehension in Parkinson's disease: Investigating early automatic and late integrational processes using event-related brain potentials.

Parkinson's disease (PD) has been associated with a general impairment of procedures and with an impairment of syntactic procedures in particular. The present study investigated comprehension processes in PD using event-related brain potentials (ERPs). PD patients and controls listened to sentences that were either correct or syntactically or semantically incorrect. The language-related ERP component correlated with semantic processes (N400) was present in both groups. In the syntactic domain, early automatic processes (early negativity) appeared normal in PD, whereas late integrational processes (P600) were modulated by this disease. The present findings suggest that the basal ganglia primarily do not support early automatic syntactic processes during comprehension but rather support processes of syntactic integration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brain potentials reflect violations of gender stereotypes

Event-related brain potentials (ERPs) were recorded while 14 males and 14 females read sentences containing a reflexive pronoun that referred to a definitionally or stereotypically male or female antecedent noun. Pronouns that disagreed with the gender definition or gender stereotype of the antecedent elicited a large-amplitude positive wave. Violations of gender definitions elicited a larger positive wave than did violations of gender stereotypes. Furthermore, the positive wave elicited by stereotype violations persisted even when subjects judged these sentences to be acceptable. Finally, female subjects exhibited larger positivities than did male subjects, regardless of whether the gender mismatch involved a definitional or stereotypical antecedent. These results are taken to indicate that ERPs are sensitive to violations of gender-based occupational stereotypes and that the ERP response to stereotype violations is similar to the P600 effect elicited by a variety of syntactic anomalies.     

Effects of age, speed of processing, and working memory on comprehension of sentences with relative clauses.

Two hundred participants, 50 in each of four age ranges (19–29, 30–49, 50–69, 70–90) were tested for working memory, speed of processing, and the processing of sentences with relative clauses. In Experiment 1, participants read four sentence types (cleft subject, cleft object, subject-subject, subject-object) in a word-by-word, non-cumulative, self-paced reading task and made speeded plausibility judgments about them. In Experiment 2, participants read two types of sentences, one of which contained a doubly center embedded relative clause. Older participants' comprehension was less accurate and there was age-related slowing of online processing times in all but the simplest sentences, which increased in syntactically complex sentences in Experiment 1. This pattern suggests an age-related decrease in the efficiency of parsing and interpretation. Slower speed of processing and lower working memory were associated with longer online processing times only in Experiment 2, suggesting that task-related operations are related to general speed of processing and working memory. Lower working memory was not associated with longer reading times in more complex sentences, consistent with the view that general working memory is not critically involved in online syntactic processing. Longer online processing at the most demanding point in the most demanding sentence was associated with better comprehension, indicating that it reflects effective processing under some certain circumstances. However, the poorer comprehension performance of older individuals indicates that their slower online processing reflects inefficient processing even at these points. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Phonological phrase boundaries constrain the online syntactic analysis of spoken sentences.

Two experiments tested whether phonological phrase boundaries constrain online syntactic analysis in French. Pairs of homophones belonging to different syntactic categories (verb and adjective) were used to create sentences with a local syntactic ambiguity (e.g., [le petit chien mort], in English, the dead little dog, vs. [le petit chien] [mord], in English, the little dog bites, where brackets indicate phonological phrase boundaries). An expert speaker recorded the sentences with either a maximally informative prosody or a minimally informative one. Participants correctly assigned the appropriate syntactic category to the target word, even without any access to the lexical disambiguating information, in both a completion task (Experiment 1) and an abstract word detection task (Experiment 2). The size of the experimental effect was modulated by the prosodic manipulation (maximally vs. minimally informative), guaranteeing that prosody played a crucial role in disambiguation. The authors discuss the implications of these results for models of online speech perception and language acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Probability and strategy: an event-related potential study of processing syntactic anomalies

Syntactic ambiguities requiring additional processing usually elicit positive going waveforms with onset latencies between 300 and 600 ms in the event-related potential (ERP). It is still unclear to what extent these components can be viewed either (a) as language specific in nature or (b) as members of the domain-unspecific P300 family of components. The present study investigates this question by means of probability manipulations applied to German sentences with subject-object ambiguities. Non-preferred object-subject (OS) word order requires structural revisions whereas the initially preferred subject-object (SO) word order does not. In the present experiment, the proportions of OS and SO structures were varied across experimental blocks (i.e., .25/.75 vs. .75/.25). The data of 20 participants reveal that ERP components were predominantly influenced when the subjects were explicitly informed about the actual proportions before each single block. In this case an early frontal positive component at about 400 ms and a subsequent posterior positivity were elicited by rare sentence structures irrespective of word order, suggesting that sentence processing was under strategic control. Conversely, participants that were not informed about sentence proportions showed larger positivities to the unpreferred OS sentences. Probability manipulations did not affect this pattern significantly. The data suggest that positivities evoked by syntactic ambiguities respond differently to probability manipulations than the P300 component.     

Event-related brain potential examination of implicit memory processes: Masked and unmasked repetition priming.

The proposition that cortically based perceptual representation systems (PRSs) are responsible for some implicit priming phenomena was examined by using event-related potentials (ERPs) in repetition and masked word priming. Experiment 1 used an explicit recognition task, in which repeated words replicated previous ERP repetition priming effects, whereas masked repetition priming revealed a new ERP effect with a posterior topography. Experiment 2 demonstrated ERP and behavioral priming in a lexical decision task for repetition and masked repetition priming. Topographical mapping of ERP repetition priming effects involved both early and late effects over the right and left anterior regions, whereas masked priming produced only an early ERP effect posteriorly. These results suggest differences between early and late ERP priming effects in terms of explicit recollection. Moreover, a posterior PRS may not be involved in some longer term implicit repetition priming effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syntactic prediction in language comprehension: Evidence from either...or.

Readers' eye movements were monitored as they read sentences in which two noun phrases or two independent clauses were connected by the word or (NP-coordination and S-coordination, respectively). The word either could be present or absent earlier in the sentence. When either was present, the material immediately following or was read more quickly, across both sentence types. In addition, there was evidence that readers misanalyzed the S-coordination structure as an NP-coordination structure only when either was absent. The authors interpret the results as indicating that the word either enabled readers to predict the arrival of a coordination structure; this predictive activation facilitated processing of this structure when it ultimately arrived, and in the case of S-coordination sentences, enabled readers to avoid the incorrect NP-coordination analysis. The authors argue that these results support parsing theories according to which the parser can build predictable syntactic structure before encountering the corresponding lexical input. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The persistence of structural priming: Transient activation or implicit learning?

Structural priming in language production is a tendency to recreate a recently uttered syntactic structure in different words. This tendency can be seen independent of specific lexical items, thematic roles, or word sequences. Two alternative proposals about the mechanism behind structural priming include (a) short-term activation from a memory representation of a priming structure and (b) longer term adaptation within the cognitive mechanisms for creating sentences, as a form of procedural learning. Two experiments evaluated these hypotheses, focusing on the persistence of structural priming. Both experiments yielded priming that endured beyond adjacent sentences, persisting over 2 intervening sentences in Experiment 1 and over 10 in Experiment 2. Although memory may have short-term consequences for some components of this kind of priming, the persisting effects are more compatible with a learning account than a transient memory account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overt and covert identification of fragmented objects inferred from performance and electrophysiological measures.

The authors investigated visual processing leading to object identification by manipulating the number of fragments and nature of the study. During the study, participants either named or drew objects in Experiment 1 and drew them all in Experiment 2. During the test, participants made an identification judgment at each of 6 different fragmentation levels for studied and new objects. Fewer fragments were needed to identify studied than unstudied objects. Reaction times (RTs) were faster for studied than unstudied objects both at identification and at the preceding level. Event-related brain potentials (ERPs) to unidentified objects were characterized by a late negativity in contrast to a positivity to identified objects. ERPs to studied but not to new objects contained a smaller and later version of the identification positivity at level just prior to identification, which was not due to differential response confidence. Much covert visual analysis and even object identification may precede overt identification, depending on the nature of prior experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiological responses to coarticulatory and word level miscues.

The influence of coarticulation cues on spoken word recognition is not yet well understood. This acoustic/phonetic variation may be processed early and recognized as sensory noise to be stripped away, or it may influence processing at a later prelexical stage. The present study used event-related potentials (ERPs) in a picture/spoken word matching paradigm to examine the temporal dynamics of stimuli systematically violating expectations at three levels: entire word (lexical), initial phoneme (phonemic), or in coarticulation cues contained in the initial phoneme (subphonemic). We found that both coarticulatory and phonemic mismatches resulted in increased negativity in the N280, interpreted as indexing prelexical processing of subphonemic information. Further analyses revealed that the point of uniqueness differentially modulated subsequent early or late negativity depending on whether the first or second segment matched expectations, respectively. Finally, it was found that word-level but not coarticulatory mismatches modulated the later-going N400 component, indicating that subphonemic information does not influence word-level selection provided no lexical change has occurred. The results indicate that acoustic/phonetic variation resulting from coarticulation is preserved in and influences spoken word recognition as it becomes available, particularly during prelexical processing. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The effects of between-source discriminability on attended and unattended auditory ERPs

Event-related potentials (ERPs) for tone pips from attended and unattended sources, which varied on discriminability, were compared with ERPs for the same stimuli recorded during performance of a visual task. This comparison revealed that Nd, the negative shift of attended relative to unattended ERPs, consisted of three components: a negativity in the attended ERP from 100 to 270 ms, a positivity in the unattended ERP from 170 ms to the end of the epoch, and a second negativity in the attended ERP from 270 to 700 ms. In general, the later onset of early Nd with more difficult between-source discriminations could be attributed to the later onset of the positivity in unattended ERPs. A number of hypotheses were advanced for the origin of the unattended positivity: the suppression of the later of two negative components in the 100-220-ms range, an enhanced P2 component, an endogenous positivity, or the resolution of a protracted negativity elicited by preceding attended stimuli.     

Eye movements and lexical ambiguity resolution: Effects of prior encounter and discourse topic.

Eye movements were monitored as participants read passages that contained 2 occurrences of a balanced ambiguous word. In Experiment 1, local context was manipulated so that the meaning of the ambiguous word either remained the same or changed from the 1st to 2nd encounter. In Experiments 2 and 3, global context was manipulated by shifting the discourse topic between the 2 instances of the ambiguous word. Gaze durations on the 2nd instance of the ambiguous word were shorter when the meaning remained consistent than when the meaning changed, and this facilitation was impervious to changes in the discourse structure. In contrast, processing time in the region immediately following the target was longer when the word meaning changed, but only when the topic of the discourse remained the same throughout the passage. When the topic was shifted, this effect disappeared. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lag invariance with forced encodings in free recall.

Describes an experiment in which 144 undergraduates read 28 sentences, each 6 words in length. The last word was a homograph for which either of 2 meanings could be biased by the context of the sentence. 6 of the homographs appeared twice, with 1, 6, or 11 sentences intervening between the 1st and 2nd presentation. For 72 of the Ss, the same meaning was biased on both occasions (condition SC), while the remaining Ss were given 2 different meanings (condition DC). In free recall of the homographs, probability of recall was an increasing function of the number of intervening sentences (lag) for condition SC, whereas this function was invariant with lag for condition DC. For both conditions, the probability of an early output of a homograph was also an increasing function of lag. Findings are interpreted within an encoding variability framework. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)