Language Comprehension Processes Research Articles

Prefrontal Cortical Circuitry and Cognitive Control in the Health and Disease

Event Abstract Back to Event Prefrontal Cortical Circuitry and Cognitive Control in the Health and Disease Cameron S. Carter1* 1 University of California at Davis, Center for Neuroscience and Imaging Research Center, United States A growing body of data suggest that while multiple neural systems in the brain are engaged during cognitive control, a general purpose dorsal prefrontal/cingulate/parietal network plays a key role in supporting processing requiring high levels of control in a manner that cuts across both traditional domains of executive functions as well as traditional cognitive processing systems. In this talk I will review the evidence for this general-purpose system and its specialized role in managing processing conflict. I will also present new data using schizophrenia as a model system of impaired cognitive control. Alternative models of impaired cognition in the illness, such as disrupted sensory processing, will be considered and results of fMRI and ERP/EEG studies that test the generality of impaired cognitive control across domains of response selection, episodic memory, language comprehension and emotion processing in the illness. These data support the domain generality of this network in healthy individuals and also suggest that a disruption of prefrontal cortical-based cognitive control systems plays a key role in higher cognitive function in schizophrenia and contribute to behavioral disorganization and functional impairment in the illness. Broader implications of these findings for our understanding of the neural basis of normal cognition as well as for the pathophysiology and treatment of schizophrenia and other psychotic disorders will be discussed. Keywords: Prefrontal Cortex, cognitive control, Schizophrenia, emotion, Language, Memory Conference: ACNS-2013 Australasian Cognitive Neuroscience Society Conference, Clayton, Melbourne, Australia, 28 Nov - 1 Dec, 2013. Presentation Type: Oral Topic: Executive Processes Citation: Carter CS (2013). Prefrontal Cortical Circuitry and Cognitive Control in the Health and Disease. Conference Abstract: ACNS-2013 Australasian Cognitive Neuroscience Society Conference. doi: 10.3389/conf.fnhum.2013.212.00196 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 15 Oct 2013; Published Online: 25 Nov 2013. * Correspondence: Dr. Cameron S Carter, University of California at Davis, Center for Neuroscience and Imaging Research Center, Davis, CA, United States, cameron.carter@ucdmc.ucdavis.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Cameron S Carter Google Cameron S Carter Google Scholar Cameron S Carter PubMed Cameron S Carter Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Novelty and processing demands in conceptual combination

In this article, we sought to isolate the processing demands of combining the concepts of modifier‐noun phrases from those of other language comprehension processes. Probe reaction time (RT) was used as an indication of the processing resources required for combining concepts. Phrase frequency (as measured by Google hit rates) was used as a metric of the degree of conceptual combination required for each phrase. Participants were asked to interpret modifier‐noun phrases using a sense‐nonsense decision (Experiment 1) and a phrase meaning access task (Experiment 2). Experiment 2 also used a lexical decision task to activate the word's individual meanings. Regression analyses for both experiments indicated that phrase frequency (indicating novelty) predicts a significant portion of the probe RT variance, such that low‐frequency phrases required more processing resources than high‐frequency phrases, when controlling for associative strength, word frequency, letter length, and lexical‐semantic activation. Overall, this study indicates that conceptual combination requires processing resources beyond those of other language processes.

A Reappraisal of Lexical Cohesion in Conversational Discourse

Cohesion, or the connectedness of discourse, has been recognized as playing a crucial role in both language production and comprehension processes. Researchers have debated about the ‘right’ number and classification of cohesive devices, as well as about their interaction with coherence and/or genre. The present study proposes an integrative model of lexical cohesion that extends previous models and argues for the difference between ‘associative cohesion’ and ‘(lexical) collocation’. Its evaluation against a corpus of 14 conversations, 7 broadcast discussions and 7 phone calls, reports the former to show almost six times as many instances of lexical ties as the latter, a difference that is attributed to the divergent features of these two genres. Apart from quantitative findings supported by statistical significance tests, qualitative analyses also show that lexical cohesion is involved in turn-taking behaviors and topic management patterns, thereby contributing to the establishment of interpersonal relationships and the expansion of generic stages in these two kinds of spoken interactions.

The Interaction of Syntactic and Lexical Information Sources in Language Processing: The Case of the Noun-verb Ambiguity

This paper reports the results of a lexical decision experiment and a selfpaced reading experiment that investigate the interaction between syntactic and lexical information in on-line language processing, using the noun-verb ambiguity in English. The results of both experiments provide support for the hypothesis whereby syntactic and lexical information are two independent factors in the process of sentence comprehension, consistent with previous work in the sense-ambiguity processing literature. Our results therefore add to the body of literature that demonstrates that the process of language comprehension is guided by numerous independent information sources, rather than syntactic information alone, as some of the earlier proposals in the field of sentence pro cessing hypothesized.

Attention to language: Novel MEG paradigm for registering involuntary language processing in the brain

Previous research indicates that, under explicit instructions to listen to spoken stimuli or in speech-oriented behavioural tasks, the brain’s responses to senseless pseudowords are larger than those to meaningful words; the reverse is true in non-attended conditions. These differential responses could be used as a tool to trace linguistic processes in the brain and their interaction with attention. However, as previous studies relied on explicit instructions to attend or ignore the stimuli, a technique for automatic attention modulation (i.e., not dependent on explicit instruction) would be more advantageous, especially when cooperation with instructions may not be guaranteed (e.g., neurological patients, children etc). Here we present a novel paradigm in which the stimulus context automatically draws attention to speech. In a non-attend passive auditory oddball sequence, rare words and pseudowords were presented among frequent non-speech tones of variable frequency and length. The low percentage of spoken stimuli guarantees an involuntary attention switch to them. The speech stimuli, in turn, could be disambiguated as words or pseudowords only in their end, at the last phoneme, after the attention switch would have already occurred. Our results confirmed that this paradigm can indeed be used to induce automatic shifts of attention to spoken input. At ∼250ms after the stimulus onset, a P3a-like neuromagnetic deflection was registered to spoken (but not tone) stimuli indicating an involuntary attention shift. Later, after the word-pseudoword divergence point, we found a larger oddball response to pseudowords than words, best explained by neural processes of lexical search facilitated through increased attention. Furthermore, we demonstrate a breakdown of this orderly pattern of neurocognitive processes as a result of sleep deprivation. The new paradigm may thus be an efficient way to assess language comprehension processes and their dynamic interaction with those of attention allocation. It does it in an automatic and task-free fashion, indicating its potential benefit for assessing uncooperative clinical populations.

Neural evidence that utterance-processing entails mentalizing: The case of irony

It is now well established that communicators interpret others' mental states through what has been called "Theory of Mind" (ToM). From a linguistic-pragmatics perspective, this mentalizing ability is considered critical because it is assumed that the linguistic code in all utterances underdetermines the speaker's meaning, leaving a vital role for ToM to fill the gap. From a neuroscience perspective, understanding others' intentions has been shown to activate a neural ToM network that includes the right and left temporal parietal junction (rTPJ, lTPJ), the medial prefrontal cortex (MPFC) and the precuneus (PC). Surprisingly, however, there are no studies - to our knowledge - that aim to uncover a direct, on-line link between language processing and ToM through neuroimaging. This is why we focus on verbal irony, an obviously pragmatic phenomenon that compels a listener to detect the speaker's (dissociated, mocking) attitude (Wilson, 2009). In the present fMRI investigation, we compare participants' comprehension of 18 target sentences as contexts make them either ironic or literal. Consider an opera singer who tells her interlocutor: "Tonight we gave a superb performance!" when the performance in question was clearly awful (making the statement ironic) or very good (making the statement literal). We demonstrate that the ToM network becomes active while a participant is understanding verbal irony. Moreover, we demonstrate - through Psychophysiological Interactions (PPI) analyses - that ToM activity is directly linked with language comprehension processes. The paradigm, its predictions, and the reported results contrast dramatically with those from seven prior fMRI studies on irony.

So that's what you meant! Event-related potentials reveal multiple aspects of context use during construction of message-level meaning

Factors that modulate the influence of contextual information on semantic processing in language comprehension have been thoroughly investigated with the N400 component of the event-related potential (ERP), a direct measure of initial contact with semantic memory. Although context has a strong and immediate impact on processing, multiple mechanisms contribute to the construction of message-level representations during normal comprehension. Some of these may be engaged after or concurrent with the formation of an initial meaning representation, and can then serve to revise or reshape meaning. In this study, ERPs were recorded while participants read plausible sentences that continuously varied in the amount of contextual constraint for the sentence-final word, defined via extensive norming data including the range of possible alternative completions for the contexts. Consistent with numerous past studies, the amplitude of the N400 was graded with expectancy, as amplitudes decreased with increasing constraint. Additionally, a left-lateralized, broad, slow negativity onsetting around 400-500 ms was largest for sentences with moderately strong constraint. Within this range of constraint, the negativity was larger for sentences with fewer alternative completions compared to those with many different ones. The timing and scalp distribution of the effect resemble brain responses linked to engagement of working memory resources, ambiguity resolution, and comprehension of jokes. Similar to cases of "frame-shifting" in non-literal language, this effect may reflect processing associated with reinterpretation or reconsideration of contextual material when multiple interpretations of a sentence were likely.

Generalisation of a novel implicit treatment for coarse coding deficit in right hemisphere brain damage: A single-participant experiment

Background: This manuscript reports generalisation effects of Contextual Constraint Treatment for an adult with right hemisphere brain damage (RHD). Contextual Constraint Treatment is designed to stimulate inefficient language comprehension processes implicitly, by providing linguistic context to prime, or constrain, the intended interpretations of treatment stimuli. The study participant had a coarse coding deficit, defined as delayed mental activation of particularly distant semantic features of words (e.g., rotten as a feature of “apple”). Treatment effects were expected to generalise to auditory comprehension of narrative discourse, and perhaps to figurative language interpretation, because coarse coding has been hypothesised and/or demonstrated to support these abilities. Aims: This treatment study aimed to induce generalisation of Contextual Constraint Treatment in an adult with RHD with inefficient coarse coding. Methods & Procedures: The participant in this study was a 75-year-old man with RHD and a coarse coding deficit. A single-participant experimental design across behaviours (stimulus lists) was used to document performance in baseline, treatment, and follow-up phases. Treatment consisted of providing brief, spoken context sentences to prestimulate, or constrain, intended interpretations of stimulus items. The participant made no explicit associations or metalinguistic judgements about the constraint sentences or stimulus words; rather these contexts served only as implicit primes. Probe tasks were adapted from prior work on coarse coding in RHD. The dependent measure was the percentage of responses that met predetermined response time criteria. There were two levels of contextual constraint, Strong and Moderate. Treatment for each item began with the provision of the Strong constraint context, to minimise the production or reinforcement of erroneous or exceedingly slow responses. Generalisation was assessed to a well-standardised measure of narrative discourse comprehension and to several metalinguistic tasks of figurative language interpretation. Outcomes & Results: Treatment-contingent gains, associated with respectable effect sizes, were evident after a brief period of treatment on one stimulus list. Generalisation occurred to untrained items, suggesting that the treatment was facilitating the underlying coarse coding process. Most importantly, generalisation was evident to narrative comprehension performance, for both overall accuracy and accuracy in answering questions about implied information, and all of these gains were maintained through three follow-up sessions. Conclusions: Although the results are still preliminary, this single-participant experimental design documents the potential for meaningful gains from a novel treatment that implicitly targets an underlying language comprehension process in an adult with RHD.

Memory Interference as a Determinant of Language Comprehension.

The parameters of the human memory system constrain the operation of language comprehension processes. In the memory literature, both decay and interference have been proposed as causes of forgetting; however, while there is a long history of research establishing the nature of interference effects in memory, the effects of decay are much more poorly supported. Nevertheless, research investigating the limitations of the human sentence processing mechanism typically focus on decay-based explanations, emphasizing the role of capacity, while the role of interference has received comparatively little attention. This paper reviews both accounts of difficulty in language comprehension by drawing direct connections to research in the memory domain. Capacity-based accounts are found to be untenable, diverging substantially from what is known about the operation of the human memory system. In contrast, recent research investigating comprehension difficulty using a retrieval-interference paradigm is shown to be wholly consistent with both behavioral and neuropsychological memory phenomena. The implications of adopting a retrieval-interference approach to investigating individual variation in language comprehension are discussed.

Neural dynamics of animacy processing in language comprehension: ERP evidence from the interpretation of classifier–noun combinations

An event-related potential experiment was conducted to investigate the temporal neural dynamics of animacy processing in the interpretation of classifier–noun combinations. Participants read sentences that had a non-canonical structure, object noun +subject noun+verb+numeral-classifier+adjective. The object noun and its classifier were either (a) congruent, (b) incongruent, but matching in animacy, or (c) incongruent, mismatching in animacy. An N400 effect was observed for both incongruent conditions, but not for additional mismatch in animacy. When only data from participants who accepted the non-canonical structure were analyzed, the animacy mismatch elicited a P600 but still no N400. These findings suggest that animacy information is not used immediately for semantic integration of nouns and their classifiers, but is used in a later analysis reflected by P600. Thus, the temporal neural dynamics of animacy processing in sentence comprehension may be modulated by the relevance of animacy to thematic interpretation.

An ERP study on whether the P600 can reflect the presence of unexpected phonology

In this study, we conducted a new approach to determine whether the P600 could reflect the presence of unexpected phonology. In the experiment, the critical Chinese characters in the poems are either original or substituted by homophones or synonyms. The N400 effect is observed only under the homophonic condition. Late positive shifts are revealed under both homophonic and synonymous conditions, but the amplitude under the homophonic condition is smaller than that under the synonymous condition. The observation of the N400 effect under the homophonic condition indicates that semantic processing occurs in Chinese poem comprehension, while the P600 effect elicited under the homophonic condition is a reflection of unfulfilled semantic expectations. The existence of the late positivity under the synonymous condition reveals that P600 can reflect the presence of unexpected phonology. Interestingly, late positivities under the two conditions both consist of two parts. A discussion ensues wherein these two parts of the late positive shift relate, respectively, to monitoring and resolution processes in language comprehension.

A novel, implicit treatment for language comprehension processes in right hemisphere brain damage: Phase I data

Background: This manuscript reports the initial phase of testing for a novel, “Contextual constraint” treatment, designed to stimulate inefficient language comprehension processes in adults with right hemisphere brain damage (RHD). Two versions of treatment were developed to target two normal comprehension processes that have broad relevance for discourse comprehension and that are often disrupted by RHD: coarse semantic coding and suppression. The development of the treatment was informed by two well-documented strengths of the RHD population. The first is consistently better performance on assessments that are implicit, or nearly so, than on explicit, metalinguistic measures of language and cognitive processing. The second is improved performance when given linguistic context that moderately-to-strongly biases an intended meaning. Treatment consisted of providing brief context sentences to prestimulate, or constrain, intended interpretations. Participants made no explicit associations or judgments about the constraint sentences; rather, these contexts served only as implicit primes. Aims: This Phase I treatment study aimed to determine the effects of a novel, implicit, Contextual Constraint treatment in adults with RHD whose coarse coding or suppression processes were inefficient. Treatment was hypothesized to speed coarse coding or suppression function in these individuals. Methods & Procedures: Three adults with RHD participated in this study, one (P1) with a coarse coding deficit and two (P2, P3) with suppression deficits. Probe tasks were adapted from prior studies of coarse coding and suppression in RHD. The dependent measure was the percentage of responses that met predetermined response time criteria. When pre-treatment baseline performance was stable, treatment was initiated. There were two levels of contextual constraint, Strong and Moderate, and treatment for each item began with the provision of the Strong constraint context. Outcomes & Results: Treatment-contingent gains were evident after brief periods of treatment, for P1 on two treatment lists, and for P2. P3 made slower but still substantial gains. Maintenance of gains was evident for P1, the only participant for whom it was measured. Conclusions: This Phase I treatment study documents the potential for considerable gains from an implicit, Contextual constraint treatment. If replicated, this approach to treatment may hold promise for individuals who do poorly with effortful, metalinguistic treatment tasks, or for whom it is desirable to minimize errors during treatment. The real test of this treatment's benefit will come from later phase studies of study, which will test broad-based generalization to various aspects of discourse comprehension.

Examining lateralized lexical ambiguity processing using dichotic and cross-modal tasks

The individual roles played by the cerebral hemispheres during the process of language comprehension have been extensively studied in tasks that require individuals to read text (for review see Jung-Beeman, 2005). However, it is not clear whether or not some aspects of the theorized laterality models of semantic comprehension are a result of the modality of presentation. Extending earlier work examining lateralized semantic processing using lexically ambiguous words, the current experiments utilized two modified lexical-decision tasks (one fully auditory and one cross-modal) with dichotically presented target stimuli. When targets were presented to the right ear/left hemisphere there was a distinct advantage for detecting words that are associated with the dominant meaning of the ambiguous word over the subordinate meaning. In contrast, for left ear/right hemisphere trials, there was either no difference between the pattern of semantic access for dominant and subordinate meaning (dichotic only) or a processing advantage for the subordinate meaning of the ambiguous word (with cross-modal presentation). These data suggest that the complimentary hemispheric strategies that allow for semantic access are not modality specific and instead characterize how the hemispheres each contribute to comprehension for both speech and text. Thus, dichotic presentation does seem to allow for the study of subtle hemispheric difference in meaning comprehension.

Listening to the sound of silence: disfluent silent pauses in speech have consequences for listeners

Silent pauses are a common form of disfluency in speech yet little attention has been paid to them in the psycholinguistic literature. The present paper investigates the consequences of such silences for listeners, using an Event-Related Potential (ERP) paradigm. Participants heard utterances ending in predictable or unpredictable words, some of which included a disfluent silence before the target. In common with previous findings using er disfluencies, the N400 difference between predictable and unpredictable words was attenuated for the utterances that included silent pauses, suggesting a reduction in the relative processing benefit for predictable words. An earlier relative negativity, topographically distinct from the N400 effect and identifiable as a Phonological Mismatch Negativity (PMN), was found for fluent utterances only. This suggests that only in the fluent condition did participants perceive the phonology of unpredictable words to mismatch with their expectations. By contrast, for disfluent utterances only, unpredictable words gave rise to a late left frontal positivity, an effect previously observed following ers and disfluent repetitions. We suggest that this effect reflects the engagement of working memory processes that occurs when fluent speech is resumed. Using a surprise recognition memory test, we also show that listeners were more likely to recognise words which had been encountered after silent pauses, demonstrating that silence affects not only the process of language comprehension but also its eventual outcome. We argue that, from a listener's perspective, one critical feature of disfluency is the temporal delay which it adds to the speech signal.

Effects of language comprehension on visual processing – MEG dissociates early perceptual and late N400 effects

We investigated whether and when information conveyed by spoken language impacts on the processing of visually presented objects. In contrast to traditional views, grounded-cognition posits direct links between language comprehension and perceptual processing. We used a magnetoencephalographic cross-modal priming paradigm to disentangle these views. In a sentence-picture verification task, pictures (e.g. of a flying duck) were paired with three sentence conditions: A feature-matching sentence about a duck in the air, a feature-mismatching sentence about a duck in a lake, and an unrelated sentence. Brain responses to pictures showed enhanced activity in the N400 time-window for the unrelated compared to both related conditions in the left temporal lobe. The M1 time-window revealed more activation for the feature-matching than for the other two conditions in the occipital cortex. These dissociable effects on early visual processing and semantic integration support models in which language comprehension engages two complementary systems, a perceptual and an abstract one.

The influence of mood on the processing of syntactic anomalies: Evidence from P600

In several domains of psychology it has been shown that mood influences the way in which we process information. So far, little is known about the relation between mood and processes of language comprehension. In the present study we explore, whether, and if so how, mood affects the processing of syntactic anomalies in real time by recording event-related potentials (ERPs). To this aim we compared the P600 effect to subject–verb agreement errors relative to correct sentences while ERPs were recorded and mood was manipulated by presenting happy or sad film clips. The prediction was that if emotional state affects processes of language comprehension this should be reflected by an interaction between mood and P600. The results were as follows: first, the mood induction procedure was effective: participants were happier after watching happy film clips and sadder after watching sad film clips compared to baseline. Second, for P600 a mood by syntactic correctness interaction was obtained for the midline and lateral electrodes. The interaction reflected a broadly distributed P600 effect for the happy mood condition and a strong reduction in P600 effect for the sad mood condition. Correlation analyses confirmed that the observed changes in P600 effect were accompanied by reliable changes in emotional state. The present ERP findings demonstrate that mood interacts with processes of language comprehension. Three possible explanations for the mood by syntactic correctness interaction are discussed; one in terms of syntactic processing, one in terms of heuristic processing, and one in terms of more general factors like attention and/or motivation.

Inhibitory processes in bilingual language comprehension: Evidence from Spanish–English interlexical homographs

This study examines how Spanish–English bilinguals select meanings of words that share the same orthography across languages but differ in meaning (interlexical homographs such as pie, meaning foot in Spanish). Bilingual participants were required to decide whether pairs of English words were related. In Experiment 1, participants were slower to respond to homographs presented along with words related to the Spanish meaning of the homograph as compared to control words. More importantly, bilinguals were slower to respond when the English translation of the Spanish homograph meaning was presented after responding to homographs. This result suggests that bilinguals inhibited the irrelevant homograph meaning. These inhibitory processes were independent of response type (yes/no) since participants were again slower to respond to the English translation when response type changed in Experiment 2. These results suggest that bilingual language selection in comprehension tasks implies inhibitory processes.

Procesos de Comprensión del Discurso y Adquisición de Segundas Lenguas: ¿Hasta qué Punto Estamos ante una Nueva Variedad de Relativismo Lingüístico?

In this paper we address issues related to comprehension processes, and how they can be affected by types of text or written discourse, and by a reader’s first or second language. To this end, we discuss the processing of narrative and expository texts, and their effects on different levels of human cognition. Likewise, we discuss the effects of texts written in different codes, that is, in first and second languages. We propose that differences in text comprehension processes occur as a function of their causal nature and of the inferences that are generated during comprehension. In terms of second language comprehension, modern research applying functional magnetic resonance imaging, or fMRI, with bilinguals is discussed in support of the notion that first language comprehension processes are generally replicated in the second language. Therefore, we focus on comprehension processes, generation of interferences, and the processing of a second language as influenced by linguistic relativism.

Right or Wrong?

How does the brain respond to statements that clash with a person's value system? We recorded event-related brain potentials while respondents from contrasting political-ethical backgrounds completed an attitude survey on drugs, medical ethics, social conduct, and other issues. Our results show that value-based disagreement is unlocked by language extremely rapidly, within 200 to 250 ms after the first word that indicates a clash with the reader's value system (e.g., "I think euthanasia is an acceptable/unacceptable..."). Furthermore, strong disagreement rapidly influences the ongoing analysis of meaning, which indicates that even very early processes in language comprehension are sensitive to a person's value system. Our results testify to rapid reciprocal links between neural systems for language and for valuation.

Modality exclusivity norms for 423 object properties

Recent work has shown that people routinely use perceptual information during language comprehension and conceptual processing, from single-word recognition to modality-switching costs in property verification. In investigating such links between perceptual and conceptual representations, the use of modality-specific stimuli plays a central role. To aid researchers working in this area, we provide a set of norms for 423 adjectives, each describing an object property, with mean ratings of how strongly that property is experienced through each of five perceptual modalities (visual, haptic, auditory, olfactory, and gustatory). The data set also contains estimates of modality exclusivity--that is, a measure of the extent to which a particular property may be considered unimodal (i.e., perceived through one sense alone). Although there already exists a number of sets of word and object norms, we provide the first set to categorize words describing object properties along the dimensions of the five perceptual modalities. We hope that the norms will be of use to researchers working at the interface between linguistic, conceptual, and perceptual systems. The modality exclusivity norms may be downloaded as supplemental materials for this article from brm.psychonomic-journals.org/content/supplemental.