Are the P600 and P3 ERP components linked to the task-evoked pupillary response as a correlate of norepinephrine activity?

During language comprehension, anomalies and ambiguities in the input typically elicit the P600 event-related potential component. Although traditionally interpreted as a specific signal of combinatorial operations in sentence processing, the component has alternatively been proposed to be a variant of the oddball-sensitive, domain-general P3 component. In particular, both components might reflect phasic norepinephrine release from the locus coeruleus (LC/NE) to motivationally significant stimuli. In this preregistered study, we tested this hypothesis by relating both components to the task-evoked pupillary response, a putative biomarker of LC/NE activity. 36 participants completed a sentence comprehension task (containing 25% morphosyntactic violations) and a non-linguistic oddball task (containing 20% oddballs), while the EEG and pupil size were co-registered. Our results showed that the task-evoked pupillary response and the ERP amplitudes of both components were similarly affected by both experimental tasks. In the oddball task, there was also a temporally specific relationship between the P3 and the pupillary response beyond the shared oddball effect, thereby further linking the P3 to NE. Because this link was less reliable in the linguistic context, we did not find conclusive evidence for or against a relationship between the P600 and the pupillary response. Still, our findings further stimulate the debate on whether language-related ERPs are indeed specific to linguistic processes or shared across cognitive domains. However, further research is required to verify a potential link between the two ERP positivities and the LC/NE system as the common neural generator.

Multivariate pattern analysis of EEG reveals nuanced impact of negation on sentence processing in the N400 and later time windows.

The neurocognitive mechanism underlying negation processing remains controversial. While negation is suggested to modulate the access of word meaning, no such evidence has been observed in the event-related potential (ERP) literature on sentence processing. In the current study, we applied both univariate ERP and multivariate pattern analysis (MVPA) methods to examine the processing of sentence negation. We investigated two types of negative congruent/incongruent sentence pairs with truth-value evaluation (e.g., "A robin is a/not a bird") and without (e.g., "The woman reads a/no book"). In the N400 time window, ERPs consistently showed increased negativity for negative and incongruent conditions. MVPA, on the other hand, revealed nuanced interactions between polarity and congruency. In the later P600 time window, MVPA but not the ERPs revealed an effect of congruency, which may be functionally distinct from the N400 window. We further used cross-decoding to show that the cognitive processes underlying the N400 window for both affirmative and negative sentences are comparable, whereas in the P600 window, only for the truth sentences, negative sentences showed a distinct pattern from their affirmative counterparts. Our results thus speak for a more interactive, but nevertheless serial and biphasic, and potentially construction-specific processing account of negation. We also discuss the advantage of applying MVPA in addition to the classical univariate methods for a better understanding of the neurobiology of negation processing and language comprehension alike.

Unpleasant words can affect the detection of morphosyntactic errors: An ERP study on individual differences.

In recent years, several ERP studies have investigated whether the early computation of agreement is permeable to the emotional content of words. Some studies have reported interactive effects of grammaticality and emotionality in the left anterior negativity (LAN) component, while others have failed to replicate these results. Furthermore, novel findings suggest that grammatical processing can elicit different neural patterns across individuals. In this study, we aim to investigate whether the interaction between grammaticality and emotionality is restricted to participants with a specific neural profile. Sixty-one female native speakers of Spanish performed an agreement judgment task in noun phrases composed of a determiner, a noun, and an unpleasant or neutral adjective that could agree or disagree in gender with the preceding noun. Our results support the existence of two different brain profiles: negative and positive dominance (individuals showing either larger LAN or larger P600 amplitudes in ungrammatical stimuli than in grammatical ones, respectively). Interestingly, the neural pattern of these two groups diverged at different points along the time course. Thus, the negative dominance group showed grammaticality effects as early as 200 ms, along with parallel and autonomous processing of grammaticality and emotionality at the LAN/N400 time window. Instead, for the positive dominance group an early interaction was found at around 200 ms, evidencing a grammaticality effect that emerged only for unpleasant words. Our findings confirm the role of individual differences in the interplay between grammar and emotion at the neural level and call for the inclusion of this perspective in studies on syntactic processing.

An ERP Study on the Processing of Subject-Verb and Object-Verb Gender Agreement in Punjabi.

This study was conducted with the aim of exploring the general parsing mechanisms involved in processing different kinds of dependency relations, namely verb agreement with subjects versus objects in Punjabi, an SOV Indo-Aryan language. Event related brain potentials (ERPs) were recorded as twenty-five native Punjabi speakers read transitive sentences. Critical stimuli were either fully acceptable as regards verb agreement, or alternatively violated gender agreement with the subject or object. A linear mixed-models analysis confirmed a P600 effect at the position of the verb for all violations, regardless of whether subject or object agreement was violated. These results thus suggest that an identical mechanism is involved in gender agreement computation in Punjabi regardless of whether the agreement is with the subject or the object argument.

How L2 Learners Process Different Means of Time Encoding in a Tenseless Language: An ERP Study of Mandarin.

In the past, research on the cognitive neural mechanism of second language (L2) learners' processing time information has focused on Indo-European languages. It has also focused on the temporal category expressed by morphological changes. However, there has been a lack of research on L2 learners' various time coding means, especially for Mandarin, which lacks morphological changes. Using event-related potentials (ERPs), we investigated the cognitive neural mechanism of L2 learners with native Indonesian background in processing two time coding means (time adverbs and aspect markers) in Chinese. Indonesian has time adverb encoding time information similar to that of Chinese, but there are no aspect markers similar to Chinese in Indonesian. We measured ERPs time locked to the time adverb " (cengjing)" and the aspect marker "verb + (verb + guo)" in two different conditions, i.e., a control condition (the correct sentence) and a temporal information violation. The experimental results showed that the native speaker group induced the biphasic N400-P600 effect under the condition of time adverb violation, and induced P600 under the condition of the aspect marker "verb + (verb + guo)" violation. Indonesian L2 learners of Chinese only elicited P600 for the violation of time adverbs, and there was no statistically significant N400 similar to that of Chinese native speakers. In the case of aspect marker violation, we observed no significant ERPs component for the Indonesian L2 learners of Chinese. Both groups of subjects induced elicited a widely distributed and sustained negativity on the post-critical words after "verb + (verb + guo)" and "(cengjing)". This showed that the neural mechanism of Indonesian L2 learners of Chinese processing Chinese time coding differs from that of Chinese native speakers.

Processing of Counterfactual Conditional Sentences with Differential Propositional Truth-Value in Mandarin Chinese: Evidence from ERP.

Although many studies document the role of propositional truth-value in human psychological reading behavior, there is a relative paucity of research examining the role of differential propositional truth-value in processing Chinese counterfactual conditionals. This study is to investigate the role of differential propositional value in processing Chinese counterfactual conditionals by means of ERPs (event-related potentials). The study is based on comprehending two types of Chinese counterfactual conditionals, which is propositional truth value introduced by two different markers of conditional conjunctions in the protasis and apodosis, such as true counterfactual conditional markers jiaru (if) & jiu (so) in the sentence wo xiang yu jiaru you tui jiu keyi zai shuixia zhixi (I think if fish had legs so they could stifle under water), and false counterfactual conditional markers ruguo (if) & namo (then) in the sentence wo xiang gou ruguo you lin namo keyi zai shuixia huxi (I think if dogs had scales, then they could breathe under water). Two counterfactual propositional values (i.e. true and false propositional values) are constructed through manipulating sentence counterfactuality between the true and false counterfactual conditional markers in the protasis and the apodosis. Twenty-four full-time Chinese college students participated in the ERP study. The results demonstrated that processing the true counterfactual propositional sentences with conditional markers jiaru (if) & jiu (so) elicited the N400 effect relative to false propositional sentences with conditional markers ruguo (if) & namo (then). Moreover, the counterfactual sentences with true propositional conditions varied from the elicitation of the N400 effect in the protasis and absence of the N400 effect in the apodosis, showing that semantic roles may gradually disappear under the impact of truth value of propositional counterfactual condition, and/or the roles of semantic anomaly was eliminated in the accumulated sentence processing. While for the false counterfactual conditional sentences, elicitations of P300 in the protasis and robust N400 effect in the apodosis were shown, indicating the increasing semantic role in the processing. Interestingly, there was the absence of the P600 effect for processing sentences with syntactic violation, suggesting little extra syntactic cost in processing sentences with false propositional condition.

Processing of complex morphosyntactic structures in French: ERP evidence from native speakers.

This event-related brain potentials (ERP) study investigated the neurocognitive mechanisms underlying the auditory processing of verbal complexity in French illustrated by the prescriptive present subjunctive mode. Using a violation paradigm, ERPs of 32 French native speakers were continuously recorded while they listened to 200 ecological French sentences selected from the INTEFRA oral corpus (2006). Participants performed an offline acceptability judgement task on each sentence, half of which contained a correct present subjunctive verbal agreement (reçoive) and the other half an incorrect present indicative one (peut). Critically, the present subjunctive mode was triggered either by verbs (Ma mère desire que j'apprenneMy mother wants me to learn) or by subordinating conjunctions (Pour qu'elle reçoiveSo that she receives). We found a delayed anterior negativity (AN) due to the length of the verbal forms and a P600 that were larger for incongruent than for congruent verbal agreement in the same time window. While the two effects were left lateralized for subordinating conjunctions, they were right lateralized for both structures with a larger effect for subordinating conjunctions than for verbs. Moreover, our data revealed that the AN/P600 pattern was larger in late position than in early ones. Taken together, these results suggest that morphosyntactic complexity conveyed by the French subjunctive involves at least two neurocognitive processes thought to support an initial morphosyntactic analysis (AN) and a syntactic revision and repair (posterior P600). These two processes may be modulated as a function of both the element (i.e., subordinating conjunction vs verb) that triggers the subjunctive mode and the moment at which this element is used while sentence processing.

Endogenous Oscillations Time-Constrain Linguistic Segmentation: Cycling the Garden Path.

Speech is transient. To comprehend entire sentences, segments consisting of multiple words need to be memorized for at least a while. However, it has been noted previously that we struggle to memorize segments longer than approximately 2.7 s. We hypothesized that electrophysiological processing cycles within the delta band (<4 Hz) underlie this time constraint. Participants' EEG was recorded while they listened to temporarily ambiguous sentences. By manipulating the speech rate, we aimed at biasing participants' interpretation: At a slow rate, segmentation after 2.7 s would trigger a correct interpretation. In contrast, at a fast rate, segmentation after 2.7 s would trigger a wrong interpretation and thus an error later in the sentence. In line with the suggested time constraint, the phase of the delta-band oscillation at the critical point in the sentence mirrored segmentation on the level of single trials, as indicated by the amplitude of the P600 event-related brain potential (ERP) later in the sentence. The correlation between upstream delta-band phase and downstream P600 amplitude implies that segmentation took place when an underlying neural oscillator had reached a specific angle within its cycle, determining comprehension. We conclude that delta-band oscillations set an endogenous time constraint on segmentation.

Musical and linguistic syntactic processing in agrammatic aphasia: An ERP study.

Language and music rely on complex sequences organized according to syntactic principles that are implicitly understood by enculturated listeners. Across both domains, syntactic processing involves predicting and integrating incoming elements into higher-order structures. According to the Shared Syntactic Integration Resource Hypothesis (SSIRH; Patel, 2003), musical and linguistic syntactic processing rely on shared resources for integrating incoming elements (e.g., chords, words) into unfolding sequences. One prediction of the SSIRH is that people with agrammatic aphasia (whose deficits are due to syntactic integration problems) should present with deficits in processing musical syntax. We report the first neural study to test this prediction: event-related potentials (ERPs) were measured in response to musical and linguistic syntactic violations in a group of people with agrammatic aphasia (n=7) compared to a group of healthy controls (n=14) using an acceptability judgement task. The groups were matched with respect to age, education, and extent of musical training. Violations were based on morpho-syntactic relations in sentences and harmonic relations in chord sequences. Both groups presented with a significant P600 response to syntactic violations across both domains. The aphasic participants presented with a reduced-amplitude posterior P600 compared to the healthy adults in response to linguistic, but not musical, violations. Participants with aphasia did however present with larger frontal positivities in response to violations in both domains. Intriguingly, extent of musical training was associated with larger posterior P600 responses to syntactic violations of language and music in both groups. Overall, these findings are not consistent with the predictions of the SSIRH, and instead suggest that linguistic, but not musical, syntactic processing may be selectively impaired in stroke-induced agrammatic aphasia. However, the findings also suggest a relationship between musical training and linguistic syntactic processing, which may have clinical implications for people with aphasia, and motivates more research on the relationship between these two domains.

Splitting event-related potentials: Modeling latent components using regression-based waveform estimation.

Event-related potentials (ERPs) provide a multidimensional and real-time window into neurocognitive processing. The typical Waveform-based Component Structure (WCS) approach to ERPs assesses the modulation pattern of components-systematic, reoccurring voltage fluctuations reflecting specific computational operations-by looking at mean amplitude in predetermined time-windows. This WCS approach, however, often leads to inconsistent results within as well as across studies. It has been argued that at least some inconsistencies may be reconciled by considering spatiotemporal overlap between components; that is, components may overlap in both space and time, and given their additive nature, this means that the WCS may fail to accurately represent its underlying latent component structure (LCS). We employ regression-based ERP (rERP) estimation to extend traditional approaches with an additional layer of analysis, which enables the explicit modeling of the LCS underlying WCS. To demonstrate its utility, we incrementally derive an rERP analysis of a recent study on language comprehension with seemingly inconsistent WCS-derived results. Analysis of the resultant regression models allows one to derive an explanation for the WCS in terms of how relevant regression predictors combine in space and time, and crucially, how individual predictors may be mapped onto unique components in LCS, revealing how these spatiotemporally overlap in the WCS. We conclude that rERP estimation allows for investigating how scalp-recorded voltages derive from the spatiotemporal combination of experimentally manipulated factors. Moreover, when factors can be uniquely mapped onto components, rERPs may offer explanations for seemingly inconsistent ERP waveforms at the level of their underlying latent component structure.

Semantic reversal anomalies under the microscope: Task and modality influences on language-associated event-related potentials.

Semantic reversal anomalies (SRAs)-sentences where an implausibility is created by reversing participant roles-have attracted much attention in the literature on the electrophysiology of language. In spite of being syntactically well formed but semantically implausible, these sentences unexpectedly elicited a monophasic P600 effect in English and Dutch rather than an N400 effect. Subsequent research revealed variability in the presence/absence of an N400 effect to SRAs depending on the language examined and the choice of verb type in English. However, most previous studies employed the same presentation modality (visual) and task (acceptability judgement). Here, we conducted two experiments and three statistical analyses to investigate the influence of stimulus modality, task demand and statistical choices on event-related potential (ERP) response patterns to SRAs in English. We reproduced a previous study's procedure and analysis (N. Bourguignon et al. (2012) Brain and Language, 122, 179-189) and further introduced between-subjects factors of task type and modality, using mixed-effects modelling to analyse the data. We observed an N400 effect to typical English SRAs (agent subject verbs, e.g. "the fries will eat the boys"), which contrasts existing literature and was not predicted by existing theories that account for SRA processing. Task demand modulated the ERPs elicited by SRAs, while auditory presentation led to increased comprehension accuracy and a more broadly distributed ERP. Finally, the statistical methods used influenced the presence/absence of ERP effects. Our results suggest a sensitivity of language-related ERP patterns to methodological parameters, and we conclude that future experiments should take this into careful consideration.

Zooming in on the cognitive neuroscience of visual narrative.

Visual narratives like comics and films often shift between showing full scenes and close, zoomed-in viewpoints. These zooms are similar to the "spotlight of attention" cast across a visual scene in perception. We here measured ERPs to visual narratives (comic strips) that used zoomed-in and full-scene panels either throughout the whole sequence context or at specific critical panels. Zoomed-in panels were automatically generated on the basis of fixations from prior participants' eye movements to the crucial content of panels (Foulsham & Cohn, 2020). We found that these fixation panels evoked a smaller N300 than full-scenes, indicative of reduced cost for object identification, but that they also evoked a slightly larger amplitude N400 response, suggesting a greater cost for accessing semantic memory with constrained content. Panels in sequences where fixation panels persisted across all positions of the sequence also evoked larger posterior P600s, implying that constrained views required more updating or revision processes throughout the sequence. Altogether, these findings suggest that constraining a visual scene to its crucial parts triggers various processes related not only to the density of its information but also to its integration into a sequential context.

Processing syntax: perspectives on language specificity.

Objective: The past few decades of research in language processing provides empirical data on the dimensions of the brain-language relationship. The methodologies used to study language processing have evidenced an immense advancement over the years, tracking real-time processing events with millisecond precision. Event-related potentials is one such method which assists to visualize the neural mechanisms that underlie language processing. Different electrophysiological components mark different components of language depending on their structural and functional aspects. Since research on language processing is expanding its boundaries, the neural mechanisms for processing syntax components have been the focus of recent investigations across the languages of the world. The present review article aims to discuss the findings of studies on syntax processing besides highlighting the functional significance of P600, the electrophysiological marker of syntax processing.Methods: Electronic databases such as Pubmed, Science Direct, Research gate, PLOS, Directory of Open Access Journals were searched for relavant articles. The review process followed PRISMA guidelines for screening, identification, and selection of articles.Results: The results of the review elucidate the need for evaluating the finer details of syntax, including morpho-syntax concerning specific language structures. Studies across the languages of the world exemplify the uniqueness in the structure of different languages that may provide varied perspectives on the universality in syntax processing.Conclusion: The present review contributes a new dimension towards understanding the nature of syntax processing with respect to language specificity.

Finding the P3 in the P600: Decoding shared neural mechanisms of responses to syntactic violations and oddball targets.

The P600 Event-Related Brain Potential, elicited by syntactic violations in sentences, is generally interpreted as indicating language-specific structural/combinatorial processing, with far-reaching implications for models of language. P600 effects are also often taken as evidence for language-like grammars in non-linguistic domains like music or arithmetic. An alternative account, however, interprets the P600 as a P3, a domain-general brain response to salience. Using time-generalized multivariate pattern analysis, we demonstrate that P3 EEG patterns, elicited in a visual Oddball experiment, account for the P600 effect elicited in a syntactic violation experiment: P3 pattern-trained MVPA can classify P600 trials just as well as P600-trained ones. A second study replicates and generalizes this finding, and demonstrates its specificity by comparing it to face- and semantic mismatch-associated EEG responses. These results indicate that P3 and P600 share neural patterns to a substantial degree, calling into question the interpretation of P600 as a language-specific brain response and instead strengthening its association with the P3. More generally, our data indicate that observing P600-like brain responses provides no direct evidence for the presence of language-like grammars, in language or elsewhere.

Language ERPs reflect learning through prediction error propagation.

Event-related potentials (ERPs) provide a window into how the brain is processing language. Here, we propose a theory that argues that ERPs such as the N400 and P600 arise as side effects of an error-based learning mechanism that explains linguistic adaptation and language learning. We instantiated this theory in a connectionist model that can simulate data from three studies on the N400 (amplitude modulation by expectancy, contextual constraint, and sentence position), five studies on the P600 (agreement, tense, word category, subcategorization and garden-path sentences), and a study on the semantic P600 in role reversal anomalies. Since ERPs are learning signals, this account explains adaptation of ERP amplitude to within-experiment frequency manipulations and the way ERP effects are shaped by word predictability in earlier sentences. Moreover, it predicts that ERPs can change over language development. The model provides an account of the sensitivity of ERPs to expectation mismatch, the relative timing of the N400 and P600, the semantic nature of the N400, the syntactic nature of the P600, and the fact that ERPs can change with experience. This approach suggests that comprehension ERPs are related to sentence production and language acquisition mechanisms.

Influence of speakers' gaze on situated language comprehension: Evidence from Event-Related Potentials.

Behavioral studies have shown that speaker gaze to objects in a co-present scene can influence listeners' sentence comprehension. To gain deeper insight into the mechanisms involved in gaze processing and integration, we conducted two ERP experiments (N = 30, Age: [18, 32] and [19, 33] respectively). Participants watched a centrally positioned face performing gaze actions aligned to utterances comparing two out of three displayed objects. They were asked to judge whether the sentence was true given the provided scene. We manipulated the second gaze cue to be either Congruent (baseline), Incongruent or Averted (Exp1)/Mutual (Exp2). When speaker gaze is used to form lexical expectations about upcoming referents, we found an attenuated N200 when phonological information confirms these expectations (Congruent). Similarly, we observed attenuated N400 amplitudes when gaze-cued expectations (Congruent) facilitate lexical retrieval. Crucially, only a violation of gaze-cued lexical expectations (Incongruent) leads to a P600 effect, suggesting the necessity to revise the mental representation of the situation. Our results support the hypothesis that gaze is utilized above and beyond simply enhancing a cued object's prominence. Rather, gaze to objects leads to their integration into the mental representation of the situation before they are mentioned.

Event-related potentials index lexical retrieval (N400) and integration (P600) during language comprehension.

The functional interpretation of two salient language-sensitive ERP components - the N400 and the P600 - remains a matter of debate. Prominent alternative accounts link the N400 to processes related to lexical retrieval, semantic integration, or both, while the P600 has been associated with syntactic reanalysis or, alternatively, to semantic integration. The often overlapping predictions of these competing accounts in extant experimental designs, however, has meant that previous findings have failed to clearly decide among them. Here, we present an experiment that directly tests the competing hypotheses using a design that clearly teases apart the retrieval versus integration view of the N400, while also dissociating a syntactic reanalysis/reprocessing account of the P600 from semantic integration. Our findings provide support for an integrated functional interpretation according to which the N400 reflects context-sensitive lexical retrieval - but not integration - processes. While the observed P600 effects were not predicted by any account, we argue that they can be reconciled with the integration view, if spatio-temporal overlap of ERP components is taken into consideration.

Input Training Matters in L2 Syntactic Representation Entrenchment: Evidence from a Follow-Up ERP Study.

The usage-based theory highlights the important role of linguistic input in language acquisition, and assumes that syntactic representations could be entrenched through usage or exposure. In the present study, we used the event-related potential technique to investigate the long-term effect of input training on second language (L2) syntactic representations entrenchment, using English subject-verb agreement structures as the stimuli. Results showed that 3 months after the training of the specific subject-verb agreement structures, a significant P600 was observed in the key region (the verb) of the sentences with syntactic violations in the experimental group, but not in the control group. This indicates that linguistic input training contributes to syntactic representations entrenchment, which can be sustained for a relatively long period, indicating a long-term effect of input training. The results suggest that linguistic input is a causal variable in L2 online syntactic processing, supporting the usage-based theory.

The effects of attention and task-relevance on the processing of syntactic violations during listening to two concurrent speech streams.

The notion of automatic syntactic analysis received support from some event-related potential (ERP) studies. However, none of these studies tested syntax processing in the presence of a concurrent speech stream. Here we present two concurrent continuous speech streams, manipulating two variables potentially affecting speech processing in a fully crossed design: attention (focused vs. divided) and task (lexical - detecting numerals vs. syntactical - detecting syntactic violations). ERPs elicited by syntactic violations and numerals as targets were compared with those for distractors (task-relevant events in the unattended speech stream) and attended and unattended task-irrelevant events. As was expected, only target numerals elicited the N2b and P3 components. The amplitudes of these components did not significantly differ between focused and divided attention. Both task-relevant and task-irrelevant syntactic violations elicited the N400 ERP component within the attended but not in the unattended speech stream. P600 was only elicited by target syntactic violations. These results provide no support for the notion of automatic syntactic analysis. Rather, it appears that task-relevance is a prerequisite of P600 elicitation, implying that in-depth syntactic analysis occurs only for attended speech under everyday listening situations.

The processing of animacy in noun-classifier combinations in reading Korean: An ERP study.

A key issue in the area of language processing is the mechanism underlying the processing of animacy information during sentence comprehension. In this ERP study, we investigated the temporal dynamics of animacy processing in Korean noun-classifier combinations that do not involve verb-noun thematic processing. We manipulated semantic and animacy relationships between nouns and their following classifiers, and there were three conditions in our experiment: (a) correct, (b) semantic mismatch, or (c) animacy mismatch. The results showed that both noun-classifier mismatch conditions evoked a biphasic N400-P600 effect, but there was no P600 difference between the two mismatch conditions. However, further analyses indicated that the animacy mismatch condition evoked a less negative-going waveform than the semantic mismatch condition in the 400-500 ms time window. Our findings suggest that the brain processes animacy information differently from other semantic features in noun-classifier combinations in Korean, and additional animacy mismatch blocked further fine-grained semantic processing. The ERP evidence also suggests that the role of animacy in sentence comprehension varies according to language type and sentence structure. Whether animacy participates in the construction of verb-noun thematic relationships in sentences may be an important factor that influences the neural patterns of animacy processing in language comprehension.