The P600-as-P3 hypothesis revisited: single-trial analyses reveal that the late EEG positivity following linguistically deviant material is reaction time aligned

Native and non-native parsing of adjective placement - An ERP study of Mandarin and English sentence processing

Adjectives in English and Mandarin are typically prenominal, but the corresponding grammatical rules vary in subtle ways. Our event-related potential (ERP) study shows that native speakers of both languages rely on similar processing mechanisms when reading sentences with anomalous noun-adjective order (e.g., the vase *white) in their first language, reflected by a biphasic N400-P600 profile. Only Mandarin native speakers showed an additional N400 on grammatical adjectives (e.g., the white vase), potentially due to atypical word-by-word presentation of lexicalized compounds. English native speakers with advanced Mandarin proficiency were tested in both languages. They processed ungrammatical noun-adjective pairs in English like English monolinguals (N400-P600), but only exhibited an N400 in Mandarin. The absent P600 effect corresponded to their (surprisingly) low proficiency with noun-adjective violations in Mandarin, questioning simple rule transfer from English grammar.

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.

Cortical networks responsive to phrase structure and subject island violations

In principle, functional neuroimaging provides uniquely informative data in addressing linguistic questions, because it can indicate distinct processes that are not apparent from behavioral data alone. This could involve adjudicating the source of unacceptability via the different patterns of elicited brain responses to different ungrammatical sentence types. However, it is difficult to interpret brain activations to syntactic violations. Such responses could reflect processes that have nothing intrinsically related to linguistic representations, such as domain-general executive function abilities. In order to facilitate the potential use of functional neuroimaging methods to identify the source of different syntactic violations, we conducted an fMRI experiment to identify the brain activation maps associated with two distinct syntactic violation types: phrase structure (created by inverting the order of two adjacent words within a sentence) and subject islands (created by extracting a wh-phrase out of an embedded subject). The comparison of these violations to control sentences surprisingly showed no indication of a generalized violation response, with almost completely divergent activation patterns. Phrase structure violations seemingly activated regions previously implicated in verbal working memory and structural complexity in sentence processing, whereas the subject islands appeared to activate regions previously implicated in conceptual-semantic processing, broadly defined. We review our findings in the context of previous research on syntactic and semantic violations using event-related potentials. We suggest that functional neuroimaging is a potentially fruitful technique in unpacking the distinct sets of cognitive processes elicited by theoretically-relevant syntactic violations, when interpreted with care and paired with appropriate control conditions.

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.

Violations of Lab-Learned Phonological Patterns Elicit a Late Positive Component

The experimental study of artificial language learning has become a widely used means of investigating the predictions of theories of language learning and representation. Although much is now known about the generalizations that learners make from various kinds of data, relatively little is known about how those representations affect speech processing. This paper presents an event-related potential (ERP) study of brain responses to violations of lab-learned phonotactics. Novel words that violated a learned phonotactic constraint elicited a larger Late Positive Component (LPC) than novel words that satisfied it. Similar LPCs have been found for violations of natively acquired linguistic structure, as well as for violations of other types of abstract generalizations, such as musical structure. We argue that lab-learned phonotactic generalizations are represented abstractly and affect the evaluation of speech in a manner that is similar to natively acquired syntactic and phonological rules.

Characterizing language production across modalities

ABSTRACTThis study investigates factors influencing lexical access in language production across modalities (signed and oral). Data from deaf and hearing signers were reanalyzed (Baus and Costa, 2015, On the temporal dynamics of sign production: An ERP study in Catalan Sign Language (LSC). Brain Research, 1609(1), 40-53. https://doi.org/10.1016/j.brainres.2015.03.013; Gimeno-Martínez and Baus, 2022, Iconicity in sign language production: Task matters. Neuropsychologia, 167, 108166. https://doi.org/10.1016/j.neuropsychologia.2022.108166) testing the influence of psycholinguistic variables and ERP mean amplitudes on signing and naming latencies. Deaf signers' signing latencies were influenced by sign iconicity in the picture signing task, and by spoken psycholinguistic variables in the word-to-sign translation task. Additionally, ERP amplitudes before response influenced signing but not translation latencies. Hearing signers' latencies, both signing and naming, were influenced by sign iconicity and word frequency, with early ERP amplitudes predicting only naming latencies. These findings highlight general and modality-specific determinants of lexical access in language production.

Understanding the Effects of Constraint and Predictability in ERP

Intuitively, strongly constraining contexts should lead to stronger probabilistic representations of sentences in memory. Encountering unexpected words could therefore be expected to trigger costlier shifts in these representations than expected words. However, psycholinguistic measures commonly used to study probabilistic processing, such as the N400 event-related potential (ERP) component, are sensitive to word predictability but not to contextual constraint. Some research suggests that constraint-related processing cost may be measurable via an ERP positivity following the N400, known as the anterior post-N400 positivity (PNP). The PNP is argued to reflect update of a sentence representation and to be distinct from the posterior P600, which reflects conflict detection and reanalysis. However, constraint-related PNP findings are inconsistent. We sought to conceptually replicate Federmeier et al. (2007) and Kuperberg et al. (2020), who observed that the PNP, but not the N400 or the P600, was affected by constraint at unexpected but plausible words. Using a pre-registered design and statistical approach maximising power, we demonstrated a dissociated effect of predictability and constraint: strong evidence for predictability but not constraint in the N400 window, and strong evidence for constraint but not predictability in the later window. However, the constraint effect was consistent with a P600 and not a PNP, suggesting increased conflict between a strong representation and unexpected input rather than greater update of the representation. We conclude that either a simple strong/weak constraint design is not always sufficient to elicit the PNP, or that previous PNP constraint findings could be an artifact of smaller sample size.

When a look is enough: Neurophysiological correlates of referential speaker gaze in situated comprehension

Behavioral studies have shown that speaker gaze to objects in a co-present scene can influence listeners' expectations about how the utterance will unfold. These findings have recently been supported by ERP studies that linked the underlying mechanisms of the integration of speaker gaze with an utterance meaning representation to multiple ERP components. This leads to the question, however, as to whether speaker gaze should be considered part of the communicative signal itself, such that the referential information conveyed by gaze can help listeners not only form expectations but also to confirm referential expectations induced by the prior linguistic context. In the current study, we investigated this question by conducting an ERP experiment (N=24, Age:[19,31]), in which referential expectations were established by linguistic context together with several depicted objects in the scene. Those expectations then could be confirmed by subsequent speaker gaze that preceded the referential expression. Participants were presented with a centrally positioned face performing gaze actions aligned to utterances comparing two out of three displayed objects, with the task to judge whether the sentence was true given the provided scene. We manipulated the gaze cue to be either Present (toward the subsequently named object) or Absent preceding contextually Expected or Unexpected referring nouns. The results provided strong evidence for gaze as being treated as an integral part of the communicative signal: While in the absence of gaze, effects of phonological verification (PMN), word meaning retrieval (N400) and sentence meaning integration/evaluation (P600) were found on the unexpected noun, in the presence of gaze effects of retrieval (N400) and integration/evaluation (P300) were solely found in response to the pre-referent gaze cue when it was directed toward the unexpected referent with attenuated effects on the following referring noun.

Pupil Dilation Response to Prosody and Syntax During Auditory Sentence Processing

Pupil dilation response has been shown to reflect different levels of sentence processing during prosodic and syntactic processing in language comprehension. Our pupillometry experiment aimed to investigate whether pupil diameter was sensitive to the auditory sentence processing involved in comprehending congruent and incongruent statements. Twenty-one participants were presented with 300 auditory stimuli consisting of syntactically and/or prosodically congruent and incongruent sentences in Turkish. The pupillary response results were significant only for syntactically incongruent sentences and for sentences that were both syntactically and prosodically incongruent. This indicates that prosody had no significant effect on its own. Based on the hypothesis that prosodic and syntactic processing require cognitive sensitivity for auditory sentence comprehension, we expected an increase in pupil diameter for both processes. However, our findings are consistent with the previous assumptions that pupil size increases during syntactic manipulation, but our findings showed that prosodic processing does not increase pupil size, contrary to previous studies.

Acute sensitization of the P3 event-related potential response to beverage images and the risk for alcohol use disorder

Previous research suggests the amplitude of the P3 event-related potential (ERP) response reflects the incentive value of the eliciting stimulus, and that individuals with trait-like lower sensitivity (LS) to the acute effects of alcohol, a potent risk factor for alcohol use disorder (AUD), tend to show exaggerated P3 ERP responses to alcohol beverage cues (compared to their peers with higher sensitivity; HS). No prior research has examined trajectories of the cue-elicited P3 response across repeated trials of nonreinforced cue presentations. Characterizing these trajectories can be informative as to potential mechanisms linking LS with increased AUD risk. Here, we tested whether individual differences in alcohol sensitivity are associated with different trial-by-trial trajectories of the P3 elicited by alcohol and nonalcohol reward cues (infrequent oddball/target stimuli) using a large sample of emerging adults (M _age = 19.53; N = 287; 55% female; 86% White; 90% right-handed) stratified for alcohol sensitivity. Multilevel models adjusted for age, sex, handedness, and alcohol use indicated that: (i) the P3 response to alcohol and nonalcohol reward cues alike sensitized (i.e., increased) across trials; (ii) across the task, the P3 response to alcohol cues was larger for the LS than the HS phenotype; and (iii) the P3 difference score (alcohol - nonalcohol) was larger for the LS than HS phenotype only across the first half of task. Findings suggest that whereas incentive value attribution may be a mechanism for alcohol cue-triggered attentional biases for both LS and HS individuals, LS individuals more consistently over-attribute incentive value to alcohol cues.

Odd-even oddball task: Evaluating event-related potentials during word discrimination compared to speech-token and tone discrimination

Tonal and speech token auditory oddball tasks have been commonly used to assess auditory processing in various populations; however, tasks using non-word sounds may fail to capture the higher-level ability to interpret and discriminate stimuli based on meaning, which are critical to language comprehension. As such, this study examines how neural signals associated with discrimination and evaluation-processes (P3b) from semantic stimuli compare with those elicited by tones and speech tokens. This study comprises of two experiments, both containing thirteen adults with normal hearing in both ears (PTA ≤ 20 dB HL). Scalp electroencephalography and auditory event related potentials were recorded in free field while they completed three different oddball tasks: (1) tones, (2) speech tokens and (3) odd/even numbers. Based on the findings of experiment one, experiment two was conducted to understand if the difference in responses from the three tasks was attributable to stimulus duration or other factors. Therefore, in experiment one, stimulus duration was not controlled and in experiment two, the duration of each stimulus was modified to be the same across all three tasks (∼400 ms). In both experiments, P3b peak latency was significantly different between all three tasks. P3b amplitude was sensitive to reaction time, with tasks that had a large reaction time variability resulting in the P3b amplitude to be smeared, thereby reducing the amplitude size. The findings from this study highlight the need to consider all factors of the task before attributing any effects to any additional process, such as semantic processing and mental effort. Furthermore, it highlights the need for more cautious interpretation of P3b results in auditory oddball tasks.

Children with autism spectrum disorder show atypical electroencephalographic response to processing contextual incongruencies

Children with autism spectrum disorder (ASD) experience difficulties with social communication, making it challenging to interpret contextual information that aids in accurately interpreting language. To investigate how the brain processes the contextual information and how this is different in ASD, we compared event-related potentials (ERPs) in response to processing visual and auditory congruent and incongruent information. Two groups of children participated in the study: 37 typically developing children and 15 children with ASD (age range = 6 to 12). We applied a language task involving auditory sentences describing congruent or incongruent images. We investigated two ERP components associated with language processing: the N400 and P600. Our results showed how children with ASD present significant differences in their neural responses in comparison with the TD group, even when their reaction times and correct trials are not significantly different from the TD group.

A Special Role of Syllables, But Not Vowels or Consonants, for Nonadjacent Dependency Learning

Successful language processing entails tracking (morpho)syntactic relationships between distant units of speech, so-called nonadjacent dependencies (NADs). Many cues to such dependency relations have been identified, yet the linguistic elements encoding them have received little attention. In the present investigation, we tested whether and how these elements, here syllables, consonants, and vowels, affect behavioral learning success as well as learning-related changes in neural activity in relation to item-specific NAD learning. In a set of two EEG studies with adults, we compared learning under conditions where either all segment types (Experiment 1) or only one segment type (Experiment 2) was informative. The collected behavioral and ERP data indicate that, when all three segment types are available, participants mainly rely on the syllable for NAD learning. With only one segment type available for learning, adults also perform most successfully with syllable-based dependencies. Although we find no evidence for successful learning across vowels in Experiment 2, dependencies between consonants seem to be identified at least passively at the phonetic-feature level. Together, these results suggest that successful item-specific NAD learning may depend on the availability of syllabic information. Furthermore, they highlight consonants' distinctive power to support lexical processes. Although syllables show a clear facilitatory function for NAD learning, the underlying mechanisms of this advantage require further research.

The neural hierarchy of consciousness

The chief undertaking in the studies of consciousness is that of unravelling "the minimal set of neural processes that are together sufficient for the conscious experience of a particular content - the neural correlates of consciousness". To this day, this crusade remains at an impasse, with a clash of two main theories: consciousness may arise either in a graded and cortically-localised fashion, or in an all-or-none and widespread one. In spite of the long-lasting theoretical debates, neurophysiological theories of consciousness have been mostly dissociated from them. Herein, a theoretical review will be put forth with the aim to change that. In its first half, we will cover the hard available evidence on the neurophysiology of consciousness, whereas in its second half we will weave a series of considerations on both theories and substantiate a novel take on conscious awareness: the levels of processing approach, partitioning the conscious architecture into lower- and higher-order, graded and nonlinear.

The more you know: Schema-congruency supports associative encoding of novel compound words. Evidence from event-related potentials

We aimed to investigate the neurocognitive mechanisms of event congruency with prior (schema) knowledge for the learning of novel compound words. Event-related potentials (ERPs) were recorded during an incidental learning task, in which novel noun-noun compounds were presented in a semantically congruent context, enabling schema-supported processing, or in a neutral context. As expected, associative memory performance was better for compounds preceded by a congruent context. Although the N400 was attenuated in the congruent condition, subsequent memory effects (SMEs) in the N400 time interval did not differ across conditions, suggesting that the processes reflected in the N400 cannot account for the memory advantage in the congruent condition. However, a parietal SME was obtained for compounds preceded by a congruent context, only, which we interpret as reflecting the schema-supported formation of a conceptual compound representation. A late frontal SME was obtained in both conditions, presumably reflecting the more general inter-item associative encoding of compound constituents.

A Functional Coupling of Brain and Behavior During Social Categorization of Faces

Considerable research has focused on how people derive information about others' social category memberships from their faces. Theoretical models posit that early extraction of task-relevant information from a face should determine the efficiency with which that face is categorized, but evidence supporting this idea has been elusive. Here, we used a novel trial-level data analytic approach to examine the relationship between two event-related potential components-the P2, indexing early attention to category-relevant information, and the P3, indexing stimulus evaluation-and the speed of overt categorization judgments. As predicted, a larger face-elicited P2 on a particular trial was associated with faster overt race or gender categorization of that face. Moreover, this association was mediated by P3 latency, indicating that extraction of more category-relevant information early in processing facilitated stimulus evaluation. These findings support continuous flow models of information processing and the long-theorized functional significance of face-elicited neurophysiological responses for social categorization.

Who speaks next? Adaptations to speaker identity in processing spoken sentences

When listening to a speaker, we need to adapt to her individual speaking characteristics, such as error proneness, accent, etc. The present study investigated two aspects of adaptation to speaker identity during processing spoken sentences in multi-speaker situations: the effect of speaker sequence across sentences and the effect of learning speaker-specific error probability. Spoken sentences were presented, cued, and accompanied by one of three portraits that were labeled as the speakers' faces. In Block 1 speaker-specific probabilities of syntax errors were 10%, 50%, or 90%; in Block 2 they were uniformly 50%. In both blocks, speech errors elicited P600 effects in the scalp recorded ERP. We found a speaker sequence effect only in Block 1: the P600 to target words was larger after speaker switches than after speaker repetitions, independent of sentence correctness. In Block 1, listeners showed higher accuracy in judging sentence correctness spoken by speakers with lower error proportions. No speaker-specific differences in target word P600 and accuracy were found in Block 2. When speakers differ in error proneness, listeners seem to flexibly adapt their speech processing for the upcoming sentence through attention reorientation and resource reallocation if the speaker is about to change, and through proactive maintenance of neural resources if the speaker remains the same.

Trait anxiety effects on late phase threatening speech processing: Evidence from electroencephalography

The effects of threatening stimuli, including threatening language, on trait anxiety have been widely studied. However, whether anxiety levels have a direct effect on language processing has not been so consistently explored. The present study focuses on event-related potential (ERP) patterns resulting from electroencephalographic (EEG) measurement of participants' (n = 36) brain activity while they perform a dichotic listening task. Participants' anxiety level was measured via a behavioural inhibition system scale (BIS). Later, participants listened to dichotically paired sentences, one neutral and the other threatening, and indicated at which ear they heard the threatening stimulus. Threatening sentences expressed threat semantically-only, prosodically-only, or both combined (congruent threat). ERPs showed a late positivity, interpreted as a late positive complex (LPC). Results from Bayesian hierarchical models provided strong support for an association between LPC and BIS score. This was interpreted as an effect of trait anxiety on deliberation processes. We discuss two possible interpretations. On the one hand, verbal repetitive thinking, as associated with anxious rumination and worry, can be the mechanism disrupting late phase deliberation processes. Instantiated by inner speech, verbal repetitive thinking might be the vehicle of anxiety-related reappraisal and/or rehearsal. On the other hand, increased BIS could be simply affecting an extended evaluation stage as proposed by multistep models, maybe due to over-engagement with threat or to task-related effects.

Referential Chains Reveal Predictive Processes and Form-to-Function Mapping: An Electroencephalographic Study Using Naturalistic Story Stimuli

In discourse pragmatics, different referential forms are claimed to be indicative of the cognitive status of a referent in the current discourse. Referential expressions thereby possess a double function: They point back to an (existing) referent (form-to-function mapping), and they are used to derive predictions about a referent’s subsequent recurrence in discourse. Existing event-related potential (ERP) research has mainly focused on the form-to-function mapping of referential expression. In the present ERP study, we explore the relationship of form-to-function mapping and prediction derived from the antecedent of referential expressions in naturalistic auditory language comprehension. Specifically, the study investigates the relationship between the form of a referential expression (pronoun vs. noun) and the form of its antecedent (pronoun vs. noun); i.e., it examines the influence of the interplay of predictions derived from an antecedent (forward-looking function) and the form-to-function mapping of an anaphor (backward-looking function) on the ERPs time-locked to anaphoric expressions. The results in the time range of the P300 and N400 allow for a dissociation of these two functions during online language comprehension.

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.

The time course of speaker-specific language processing

Listeners are sensitive to a speaker's individual language use and generate expectations for particular speakers. It is unclear, however, how such expectations affect online language processing. In the present EEG study, we presented thirty-two participants with auditory sentence stimuli of two speakers. Speakers differed in their use of two particular syntactic structures, easy subject-initial SOV structures and more difficult object-initial OSV structures. One speaker, the SOV-Speaker, had a high proportion of SOV sentences (75%) and a low proportion of OSV sentences (25%), and vice-versa for the OSV-Speaker. Participants were exposed to the speakers' individual language use in a training session followed by a test session on the consecutive day. ERP-results show that early stages of sentence processing are driven by syntactic processing only and are unaffected by speaker-specific expectations. In a late stage, however, an interaction between speaker and syntax information was observed. For the SOV-Speaker condition, the classical P600-effect reflected the effort of processing difficult and unexpected sentence structures. For the OSV-Speaker condition, both structures elicited different responses on frontal electrodes, possibly indexing effort to switch from a local speaker model to a global model of language use. Overall, the study identifies distinct neural mechanisms related to speaker-specific expectations.

Situating language in a minimal social context: how seeing a picture of the speaker's face affects language comprehension

Natural use of language involves at least two individuals. Some studies have focused on the interaction between senders in communicative situations and how the knowledge about the speaker can bias language comprehension. However, the mere effect of a face as a social context on language processing remains unknown. In the present study, we used event-related potentials to investigate the semantic and morphosyntactic processing of speech in the presence of a photographic portrait of the speaker. In Experiment 1, we show that the N400, a component related to semantic comprehension, increased its amplitude when processed within this minimal social context compared to a scrambled face control condition. Hence, the semantic neural processing of speech is sensitive to the concomitant perception of a picture of the speaker's face, even if irrelevant to the content of the sentences. Moreover, a late posterior negativity effect was found to the presentation of the speaker's face compared to control stimuli. In contrast, in Experiment 2, we found that morphosyntactic processing, as reflected in left anterior negativity and P600 effects, is not notably affected by the presence of the speaker's portrait. Overall, the present findings suggest that the mere presence of the speaker's image seems to trigger a minimal communicative context, increasing processing resources for language comprehension at the semantic level.

An ERP index of real-time error correction within a noisy-channel framework of human communication

Recent evidence suggests that language processing is well-adapted to noise in the input (e.g., spelling or speech errors, misreading or mishearing) and that comprehenders readily correct the input via rational inference over possible intended sentences given probable noise corruptions. In the current study, we probed the processing of noisy linguistic input, asking whether well-studied ERP components may serve as useful indices of this inferential process. In particular, we examined sentences where semantic violations could be attributed to noise-for example, in "The storyteller could turn any incident into an amusing antidote", where the implausible word "antidote" is orthographically and phonologically close to the intended "anecdote". We found that the processing of such sentences-where the probability that the message was corrupted by noise exceeds the probability that it was produced intentionally and perceived accurately-was associated with a reduced (less negative) N400 effect and an increased P600 effect, compared to semantic violations which are unlikely to be attributed to noise ("The storyteller could turn any incident into an amusing hearse"). Further, the magnitudes of these ERP effects were correlated with the probability that the comprehender retrieved a plausible alternative. This work thus adds to the growing body of literature that suggests that many aspects of language processing are optimized for dealing with noise in the input, and opens the door to electrophysiologic investigations of the computations that support the processing of imperfect input.

An Event-Related Brain Potential (ERP) Study of Complex Anaphora in Spanish

This study examines the event- related brain potential (ERP) of 25 Mexican monolingual Spanish-speakers when reading Spanish sentences with single entity anaphora or complex anaphora. Complex anaphora is an expression that refer to propositions, states, facts or events while, a single entity anaphora is an expression that refers back to a concrete object. Here we compare the cognitive cost in processing a single entity anaphora [ésta feminine; La renuncia (resignation)] from a complex anaphora [esto neuter; La renuncia fue aceptada (The resignation was accepted)]. Ésta elicited a larger positive peak at 200 ms, and esto elicited a larger frontal negativity around 400 ms. The positivity resembles the P200 component, and its amplitude is thought to represent an interaction between predictive qualities in sentence processing (i.e., graphical similarity and frequency of occurrence). Unlike parietal negativities (typical N400), frontal negativities are thought to represent the ease by which pronouns are linked with its antecedent, and how easy the information is recovered from short-term memory. Thus, the complex anaphora recruited more cognitive resources than the single entity anaphora. We also included an ungrammatical control sentence [éste masculine; La renuncia (resignation)] to better understand the unique processes behind complex anaphoric resolution, as opposed to just general difficulty in sentence processing. In this case, event-related potentials (ERPs) elicited by éste masculine and ésta feminine were compared. Again, ésta elicited a larger P200. However, different from the experimental condition, a left anterior negativity (LAN) effect was observed for éste; the ungrammatical condition. Altogether, the present research provides electrophysiological evidence indicating that demonstrative pronouns with different morphosyntactic features (i.e., gender) and discourse parameters (i.e., single entity or complex referent) interact during the first stage of anaphoric processing of anaphora. This stage initiated as early as 200 milliseconds after the pronoun onset and probably ends around 400 ms.

Sequential adaptation effects reveal proactive control in processing spoken sentences: Evidence from event-related potentials

How domain-general cognitive control is engaged in language processing remains debated. We address how linguistic processes are monitored and regulated by analyzing the effects of previous-trial sentence correctness on the P600 component of the event-related potential (ERP) in the current-trial. In data from a previous experiment about processing spoken sentences, P600 amplitudes to both correct and incorrect words in current sentences were smaller after incorrect as compared to correct previous sentences. Therefore, the detection of speech errors may initiate sustained proactive control over the monitoring demands for upcoming sentences. No sequential adaptation was found in the difference between P600 amplitudes to incorrect and correct current conditions. We propose that the P600 reflects the reactive reanalysis of speech processing and/or the resolution of linguistic conflicts, but is also sensitive to proactive speech monitoring, an important aspect of cognitive control.

Using multilevel models for the analysis of event-related potentials

Multilevel modeling (MLM) is becoming increasingly accessible and popular in the analysis of event-related potentials (ERPs). In this article, we review the benefits of MLM for analyzing psychophysiological data, which often contains repeated observations within participants, and introduce some of the decision-making points in the analytic process, including how to set up the data set, specify the model, conduct hypothesis tests, and visualize the model estimates. We highlight how the use of MLM can extend the types of theoretical questions that can be answered using ERPs, including investigations of how ERPs vary meaningfully across trials within a testing session. We also address reporting practices and provide tools to calculate effect sizes and simulate power curves. Ultimately, we hope this review contributes to emerging best practices for the use of MLM with psychophysiological data.

Neurobehavioral Correlates of Surprisal in Language Comprehension: A Neurocomputational Model

Expectation-based theories of language comprehension, in particular Surprisal Theory, go a long way in accounting for the behavioral correlates of word-by-word processing difficulty, such as reading times. An open question, however, is in which component(s) of the Event-Related brain Potential (ERP) signal Surprisal is reflected, and how these electrophysiological correlates relate to behavioral processing indices. Here, we address this question by instantiating an explicit neurocomputational model of incremental, word-by-word language comprehension that produces estimates of the N400 and the P600-the two most salient ERP components for language processing-as well as estimates of "comprehension-centric" Surprisal for each word in a sentence. We derive model predictions for a recent experimental design that directly investigates "world-knowledge"-induced Surprisal. By relating these predictions to both empirical electrophysiological and behavioral results, we establish a close link between Surprisal, as indexed by reading times, and the P600 component of the ERP signal. The resultant model thus offers an integrated neurobehavioral account of processing difficulty in language comprehension.

Selective adaptation in sentence comprehension: Evidence from event-related brain potentials

In this study, two event-related potential experiments were conducted to investigate whether readers adapt their expectations to morphosyntactically (Experiment 1) or semantically (Experiment 2) anomalous sentences when they are repeatedly exposed to them. To address this issue, we experimentally manipulated the probability of occurrence of grammatical sentences and syntactically and semantically anomalous sentences through experiments. For the low probability block, anomalous sentences were presented less frequently than grammatical sentences (with a ratio of 1 to 4), while they were presented as frequently as grammatical sentences in the equal probability block. Experiment 1 revealed a smaller P600 effect for morphosyntactic violations in the equal probability block than in the low probability block. Linear mixed-effects models were used to examine how the size of the P600 effect changed as the experiment went along. The results showed that the smaller P600 effect of the equal probability block resulted from an amplitude's decline in morphosyntactically violated sentences over the course of the experiment, suggesting an adaptation to morphosyntactic violations. In Experiment 2, semantically anomalous sentences elicited a larger N400 effect than their semantically natural counterparts regardless of probability manipulation. Little evidence was found in favour of adaptation to semantic violations in that the processing cost associated with the N400 did not decrease over the course of the experiment. Therefore, a dynamic aspect of language-processing system was demonstrated in this study. We will discuss why the language-processing system shows a selective adaptation to morphosyntactic violations.

Concurrent use of animacy and event-knowledge during comprehension: Evidence from event-related potentials

In two ERP experiments, we investigated whether readers prioritize animacy over real-world event-knowledge during sentence comprehension. We used the paradigm of Paczynski and Kuperberg (2012), who argued that animacy is prioritized based on the observations that the 'related anomaly effect' (reduced N400s for context-related anomalous words compared to unrelated words) does not occur for animacy violations, and that animacy violations but not relatedness violations elicit P600 effects. Participants read passive sentences with plausible agents (e.g., The prescription for the mental disorder was written by the psychiatrist) or implausible agents that varied in animacy and semantic relatedness (schizophrenic/guard/pill/fence). In Experiment 1 (with a plausibility judgment task), plausible sentences elicited smaller N400s relative to all types of implausible sentences. Crucially, animate words elicited smaller N400s than inanimate words, and related words elicited smaller N400s than unrelated words, but Bayesian analysis revealed substantial evidence against an interaction between animacy and relatedness. Moreover, at the P600 time-window, we observed more positive ERPs for animate than inanimate words and for related than unrelated words at anterior regions. In Experiment 2 (without judgment task), we observed an N400 effect with animacy violations, but no other effects. Taken together, the results of our experiments fail to support a prioritized role of animacy information over real-world event-knowledge, but they support an interactive, constraint-based view on incremental semantic processing.

Tea With Milk? A Hierarchical Generative Framework of Sequential Event Comprehension

To make sense of the world around us, we must be able to segment a continual stream of sensory inputs into discrete events. In this review, I propose that in order to comprehend events, we engage hierarchical generative models that "reverse engineer" the intentions of other agents as they produce sequential action in real time. By generating probabilistic predictions for upcoming events, generative models ensure that we are able to keep up with the rapid pace at which perceptual inputs unfold. By tracking our certainty about other agents' goals and the magnitude of prediction errors at multiple temporal scales, generative models enable us to detect event boundaries by inferring when a goal has changed. Moreover, by adapting flexibly to the broader dynamics of the environment and our own comprehension goals, generative models allow us to optimally allocate limited resources. Finally, I argue that we use generative models not only to comprehend events but also to produce events (carry out goal-relevant sequential action) and to continually learn about new events from our surroundings. Taken together, this hierarchical generative framework provides new insights into how the human brain processes events so effortlessly while highlighting the fundamental links between event comprehension, production, and learning.

Common Ground Information Affects Reference Resolution: Evidence From Behavioral Data, ERPs, and Eye-Tracking

One of the most important social cognitive skills in humans is the ability to “put oneself in someone else’s shoes,” that is, to take another person’s perspective. In socially situated communication, perspective taking enables the listener to arrive at a meaningful interpretation of what is said (sentence meaning) and what is meant (speaker’s meaning) by the speaker. To successfully decode the speaker’s meaning, the listener has to take into account which information he/she and the speaker share in their common ground (CG). We here further investigated competing accounts about when and how CG information affects language comprehension by means of reaction time (RT) measures, accuracy data, event-related potentials (ERPs), and eye-tracking. Early integration accounts would predict that CG information is considered immediately and would hence not expect to find costs of CG integration. Late integration accounts would predict a rather late and effortful integration of CG information during the parsing process that might be reflected in integration or updating costs. Other accounts predict the simultaneous integration of privileged ground (PG) and CG perspectives. We used a computerized version of the referential communication game with object triplets of different sizes presented visually in CG or PG. In critical trials (i.e., conflict trials), CG information had to be integrated while privileged information had to be suppressed. Listeners mastered the integration of CG (response accuracy 99.8%). Yet, slower RTs, and enhanced late positivities in the ERPs showed that CG integration had its costs. Moreover, eye-tracking data indicated an early anticipation of referents in CG but an inability to suppress looks to the privileged competitor, resulting in later and longer looks to targets in those trials, in which CG information had to be considered. Our data therefore support accounts that foresee an early anticipation of referents to be in CG but a rather late and effortful integration if conflicting information has to be processed. We show that both perspectives, PG and CG, contribute to socially situated language processing and discuss the data with reference to theoretical accounts and recent findings on the use of CG information for reference resolution.

Brain potentials reveal differential processing of masculine and feminine grammatical gender in native Spanish speakers

Studies of Spanish grammatical gender have shown that native speakers exploit gender cues in determiners to facilitate speech processing and are sensitive to gender mismatches. However, past research has not considered attested distributional asymmetries between masculine and feminine gender, collapsing performance on trials with one or the other gender into a single analysis. We use event-related potentials to investigate whether masculine and feminine grammatical gender elicit qualitatively different brain responses. Forty monolingual Spanish speakers read sentences that were well-formed or contained determiner-noun gender violations. Half of the nouns were masculine and the other half were feminine. Consistent with previous research, brain responses varied along a continuum between LAN- and P600-dominant effects for both gender categories. However, results showed that individuals' ERP response dominance (LAN/P600) systematically differed across the two genders: participants who showed a LAN-dominant response to masculine-noun violations were more likely to show a P600 effect in response to feminine-noun violations. Correlations with individual difference measures further revealed that responses to masculine-noun violations were modulated by performance on the AX-CPT, a measure of cognitive control, whereas responses to feminine-noun violations were modulated by lexical knowledge, as indexed by verbal fluency. Together, the results demonstrate that even when processing features of language that belong to the same "natural class," native speakers can exhibit patterns of brain activity attuned to distributional patterns of language use. The inherent variability in native speaker processing is, therefore, an important factor when explaining purported deviations from the "native norm" reported in other types of populations.

Gricean Expectations in Online Sentence Comprehension: An ERP Study on the Processing of Scalar Inferences

There is substantial support for the general idea that a formalization of comprehenders' expectations about the likely next word in a sentence helps explaining data related to online sentence processing. While much research has focused on syntactic, semantic, and discourse expectations, the present event-related potentials (ERPs) study investigates neurolinguistic correlates of pragmatic expectations, which arise when comprehenders expect a sentence to conform to Gricean Maxims of Conversation. For predicting brain responses associated with pragmatic processing, we introduce a formal model of such Gricean pragmatic expectations, using an idealized incremental interpreter. We examine whether pragmatic expectancies derived from this model modulate the amplitude of the N400, a component that has been associated with predictive processing. As part of its parameterization, the model distinguishes genuine pragmatic interpreters, who expect maximally informative true utterances, from literal interpreters, who only expect truthfulness. We explore the model's non-trivial predictions for an experimental setup which uses picture-sentence verification with ERPs recorded at several critical positions in sentences containing the scalar implicature trigger some. We find that Gricean expectations indeed affect the N400, largely in line with the predictions of our model, but also discuss discrepancies between model predictions and observations critically.

Lack of selectivity for syntax relative to word meanings throughout the language network

To understand what you are reading now, your mind retrieves the meanings of words and constructions from a linguistic knowledge store (lexico-semantic processing) and identifies the relationships among them to construct a complex meaning (syntactic or combinatorial processing). Do these two sets of processes rely on distinct, specialized mechanisms or, rather, share a common pool of resources? Linguistic theorizing, empirical evidence from language acquisition and processing, and computational modeling have jointly painted a picture whereby lexico-semantic and syntactic processing are deeply inter-connected and perhaps not separable. In contrast, many current proposals of the neural architecture of language continue to endorse a view whereby certain brain regions selectively support syntactic/combinatorial processing, although the locus of such "syntactic hub", and its nature, vary across proposals. Here, we searched for selectivity for syntactic over lexico-semantic processing using a powerful individual-subjects fMRI approach across three sentence comprehension paradigms that have been used in prior work to argue for such selectivity: responses to lexico-semantic vs. morpho-syntactic violations (Experiment 1); recovery from neural suppression across pairs of sentences differing in only lexical items vs. only syntactic structure (Experiment 2); and same/different meaning judgments on such sentence pairs (Experiment 3). Across experiments, both lexico-semantic and syntactic conditions elicited robust responses throughout the left fronto-temporal language network. Critically, however, no regions were more strongly engaged by syntactic than lexico-semantic processing, although some regions showed the opposite pattern. Thus, contra many current proposals of the neural architecture of language, syntactic/combinatorial processing is not separable from lexico-semantic processing at the level of brain regions-or even voxel subsets-within the language network, in line with strong integration between these two processes that has been consistently observed in behavioral and computational language research. The results further suggest that the language network may be generally more strongly concerned with meaning than syntactic form, in line with the primary function of language-to share meanings across minds.

Lack of selectivity for syntax relative to word meanings throughout the language network

To understand what you are reading now, your mind retrieves the meanings of words and constructions from a linguistic knowledge store (lexico-semantic processing) and identifies the relationships among them to construct a complex meaning (syntactic or combinatorial processing). Do these two sets of processes rely on distinct, specialized mechanisms or, rather, share a common pool of resources? Linguistic theorizing, empirical evidence from language acquisition and processing, and computational modeling have jointly painted a picture whereby lexico-semantic and syntactic processing are deeply inter-connected and perhaps not separable. In contrast, many current proposals of the neural architecture of language continue to endorse a view whereby certain brain regions selectively support syntactic/combinatorial processing, although the locus of such "syntactic hub", and its nature, vary across proposals. Here, we searched for selectivity for syntactic over lexico-semantic processing using a powerful individual-subjects fMRI approach across three sentence comprehension paradigms that have been used in prior work to argue for such selectivity: responses to lexico-semantic vs. morpho-syntactic violations (Experiment 1); recovery from neural suppression across pairs of sentences differing in only lexical items vs. only syntactic structure (Experiment 2); and same/different meaning judgments on such sentence pairs (Experiment 3). Across experiments, both lexico-semantic and syntactic conditions elicited robust responses throughout the left fronto-temporal language network. Critically, however, no regions were more strongly engaged by syntactic than lexico-semantic processing, although some regions showed the opposite pattern. Thus, contra many current proposals of the neural architecture of language, syntactic/combinatorial processing is not separable from lexico-semantic processing at the level of brain regions-or even voxel subsets-within the language network, in line with strong integration between these two processes that has been consistently observed in behavioral and computational language research. The results further suggest that the language network may be generally more strongly concerned with meaning than syntactic form, in line with the primary function of language-to share meanings across minds.

Reduced right-hemisphere ERP P600 grammaticality effect is associated with greater right-hemisphere inhibition: Evidence from right-handers with familial sinistrality

The present study examined the hypothesis that left hemisphere (LH) equivalent language capabilities in the right hemisphere (RH) are inhibited in neurologically intact individuals by testing healthy young right-handers with a history of familial sinistrality (FS+, i.e. with at least one left handed biological relative), a population documented to show greater variability for RH language processing. Event-Related Potential (ERP) and split visual field presentation techniques were combined to assess LH- and RH- biased responses to syntactic category violations. In addition, a bilateral flanker task was used to measure inter-hemispheric inhibition ability in the same set of participants. Replicating prior findings, in addition to the LH-biased P600 grammaticality effect previously seen for right-handers in general, a fair amount, though not all, of FS + right-handers showed RH-biased P600 responses, leading to a reliable RH P600 grammaticality effect at the group level. Capitalizing on the variability of RH P600 responses, our results further revealed that reduced RH-biased P600 effects were reliably correlated with more effective RH inhibition (indexed by smaller reaction time differences between incongruent and neutral flankers presented to the RH via the left visual field). These results corroborated previous findings that the RH is capable of processing syntactic information in a manner qualitatively similar to that in the LH and further demonstrated that LH-equivalent processing in the RH as indexed by the P600 responses is modulated by RH inhibition, contributing to inter-individual variability in syntactic lateralization.

The role of semantics and repair processes in article-noun gender disagreement in Italian: An ERP study

In this sentence reading study, we used event-related potentials (ERPs) to investigate the processing mechanism of article-noun gender disagreement in two kinds of nouns in Italian. The first are nouns with syntactic gender (il treno_M 'train'; la sedia_F 'chair') for which the processing and repair of gender disagreement entails only one repair option, namely for the article (morphosyntactic repair). The second kind are nouns with semantic gender (il bambino_M 'boy', la bambina_F 'girl'). Here, there are two options for processing and repairing gender mismatch: repairing the article (morphosyntactic repair) or repairing the noun (both morphosyntactic and semantic repair). Both classes of nouns elicited the LAN, indicating that gender disagreement is always registered at the morphosyntactic level. In addition, the P600 was elicited in both conditions, but was larger for semantic gender, reflecting a more complex repair for this class of nouns.

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.

Growing Random Forests reveals that exposure and proficiency best account for individual variability in L2 (and L1) brain potentials for syntax and semantics

Late second language (L2) learners report difficulties in specific linguistic areas such as syntactic processing, presumably because brain plasticity declines with age (following the critical period hypothesis). While there is also evidence that L2 learners can achieve native-like online-processing with sufficient proficiency (following the convergence hypothesis), considering multiple mediating factors and their impact on language processing has proven challenging. We recorded EEG while native (n = 36) and L2-speakers of French (n = 40) read sentences that were either well-formed or contained a syntactic-category error. a lexical-semantic anomaly, or both. Consistent with the critical period hypothesis, group differences revealed that while native speakers elicited a biphasic N400-P600 in response to ungrammatical sentences, L2 learners as a group only elicited an N400. However, individual data modeling using a Random Forests approach revealed that language exposure and proficiency are the most reliable predictors in explaining ERP responses, with N400 and P600 effects becoming larger as exposure to French as well as proficiency increased, as predicted by the convergence hypothesis.

Expectancy effects in the EEG during joint and spontaneous word-by-word sentence production in German

Our aim in the present study is to measure neural correlates during spontaneous interactive sentence production. We present a novel approach using the word-by-word technique from improvisational theatre, in which two speakers jointly produce one sentence. This paradigm allows the assessment of behavioural aspects, such as turn-times, and electrophysiological responses, such as event-related-potentials (ERPs). Twenty-five participants constructed a cued but spontaneous four-word German sentence together with a confederate, taking turns for each word of the sentence. In 30% of the trials, the confederate uttered an unexpected gender-marked article. To complete the sentence in a meaningful way, the participant had to detect the violation and retrieve and utter a new fitting response. We found significant increases in response times after unexpected words and - despite allowing unscripted language production and naturally varying speech material - successfully detected significant N400 and P600 ERP effects for the unexpected word. The N400 EEG activity further significantly predicted the response time of the subsequent turn. Our results show that combining behavioural and neuroscientific measures of verbal interactions while retaining sufficient experimental control is possible, and that this combination provides promising insights into the mechanisms of spontaneous spoken dialogue.

Studying brain activity during word-by-word interactions using wireless EEG

We introduce here the word-by-word paradigm, a dynamic setting, in which two people take turns in producing a single sentence. This task requires a high degree of coordination between the partners and the simplicity of the task allows us to study with sufficient experimental control behavioral and neural processes that underlie this controlled interaction. For this study, 13 pairs of individuals engaged in a scripted word-by-word interaction, while we recorded the neural activity of both participants simultaneously using wireless EEG. To study expectation building, different semantic contexts were primed for each participant. Semantically unexpected continuations were introduced in 25% of all sentences. In line with the hypothesis, we observed amplitude differences for the P200-N400-P600 ERPs for unexpected compared to expected words. Moreover, we could successfully assess speech and reaction times. Our results show that it is possible to measure ERPs and RTs to semantically unexpected words in a dyadic interactive scenario.

An alternative structure rescues failed semantics? Strong global expectancy reduces local-mismatch N400 in Chinese flexible structures

During comprehension of a hierarchical structure, semantic integration between sequential, mismatched sentential constituents does not proceed when the later word in the sequence (e.g., the noun in the verb + classifier + noun) can be assigned an alternative role in the sentence (e.g., as a modifier of a subsequent object noun) (Zhang et al., 2011). Using electrophysiological measures, we examined how the availability of an alternative structure and whether the reader is motivated to generate an alternative structure affect semantic integration in a hierarchical structure. The same set of sentences was employed in three experiments in which the semantic congruency between the adjective and the object noun in the local structure and the sentential-contextual expectancy towards a noun were manipulated simultaneously. The reader's motivation was manipulated by tasks in which they made semantic acceptability judgment (Experiment 1), passively viewed sentences for comprehension (Experiment 2), or actively predicted the upcoming word and monitored the compatibility between the anticipated and the actual input (Experiment 3). Stronger contextual expectancy reduced N400 responses to the object noun regardless of semantic congruency, indicating that strengthening the constraints of an alternative argument decreased the effort of semantic integration between incompatible local constituents. Relative to weaker expectancy, the incongruent noun preceded by a stronger expectancy context elicited reduced N400 responses when no active prediction was demanded but showed equal amplitudes when such a demand was high. These findings demonstrate that the semantic failure in a flexible structure is likely to be resolved by the comprehender's motivation to generate an alternative structure based on the active use of contextual expectancy information, thus highlighting the "role-dependent semantic processing" during sentence comprehension.

Verbing nouns and nouning verbs: Using a balanced design provides ERP evidence against "syntax-first" approaches to sentence processing

In this event-related potential (ERP) study we reevaluate syntax-first approaches to sentence processing by implementing a novel paradigm in French that includes correct sentences, pure syntactic category violations, lexical-semantic anomalies, and combined anomalies. Our balanced design systematically controlled for target word (noun vs. verb) and the context immediately preceding it. Group results from 36 native speakers of Quebec French revealed that, up to 300 ms, ERPs elicited by syntactic category violations were comparable with ERP responses to correct sentences, showing that there is no early activation reflecting syntactic category identification. Instead, in response to all anomalous conditions, we observed an N400 followed by a P600. Combined anomalies yielded additive effects of syntactic category and lexical-semantic anomalies on the N400, and a large P600 effect similar to the one observed in the pure syntactic condition. These results provide strong evidence against the hypothesis that (i) syntactic categories are processed first, and (ii) that syntactic category errors "block" lexical-semantic processing. Further, the N400 effect in response to pure syntactic category violations reflects a mismatch detection between a predicted word-stem and the actual target. This mechanism takes place simultaneously (and potentially in parallel) with lexical-semantic processing. In contrast, an interaction of syntax and semantics for the P600 reveals that the same neurocognitive resources are recruited for syntactic and semantic integration, both promoted by the implementation of an acceptability judgement task in our design. Additional analyses of individual data complemented these observations: during sentence processing, participants did not rely on one single cognitive mechanism reflected by either the N400 or the P600 effect but on both, suggesting that the biphasic N400-P600 ERP wave can indeed be considered to be an index of phrase-structure violations in most individuals, at least if they are realized on content words.

The N400 for brain computer interfacing: complexities and opportunities

The N400 is an event related potential that is evoked in response to conceptually meaningful stimuli. It is for instance more negative in response to incongruent than congruent words in a sentence, and more negative for unrelated than related words following a prime word. This sensitivity to semantic content of a stimulus in relation to the mental context of an individual makes it a signal of interest for Brain Computer Interfaces. A complicating aspect is the number of factors that can affect the N400 amplitude. In this paper, we provide an accessible overview of this range of N400 effects, and survey the three main BCI application areas that currently exploit the N400: (1) exploiting the semantic processing of faces to enhance matrix speller performance, (2) detecting language processing in patients with Disorders of Consciousness, and (3) using semantic stimuli to probe what is on a user's mind. Drawing on studies from these application areas, we illustrate that the N400 can successfully be exploited for BCI purposes, but that the signal-to-noise ratio is a limiting factor, with signal strength also varying strongly across subjects. Furthermore, we put findings in context of the general N400 literature, noting open questions and identifying opportunities for further research.

Detection of arithmetic violations during sleep

Can the sleeping brain develop predictions of future auditory stimuli? Past research demonstrated disrupted prediction capabilities during sleep in the context of novel, arbitrary auditory sequences, but the availability of overlearned knowledge already stored in long-term memory could still be preserved. We tested the sleeping brain capabilities to detect violations of simple arithmetic facts. Sleeping participants were presented with spoken arithmetic facts such as "two plus two is nine" and brain responses to correct or incorrect results were recorded in electro and magneto-encephalography. Sleep responses were compared to both attentive and inattentive wakefulness. During attentive wakefulness, arithmetic violations elicited a succession of N400 and P600 effects, whereas no such activations could be recorded in sleep or in inattentive wakefulness. Still, small but significant effects remained in sleep, advocating for a preserved but partial accessibility to arithmetic facts stored in long-term memory and preserved predictions of low-level and already learned knowledge. Those effects were very different from residual activities seen in inattention, highlighting the differences of information processing between the sleeping and the inattentive brain.

Language Processing as a Precursor to Language Change: Evidence From Icelandic

One of the main characteristics of human languages is that they are subject to fundamental changes over time. However, because of the long transitional periods involved, the internal dynamics of such changes are typically inaccessible. Here, we present a new approach to examining language change via its connection to language comprehension. By means of an EEG experiment on Icelandic, a prominent current example of a language in transition, we show that the neurophysiological responses of native speakers already reflect projected changes that are not yet apparent in their overt behavior. Neurocognitive measures thus offer a means of predicting, rather than only retracing, language change.

A Tale of Two Positivities and the N400: Distinct Neural Signatures Are Evoked by Confirmed and Violated Predictions at Different Levels of Representation

It has been proposed that hierarchical prediction is a fundamental computational principle underlying neurocognitive processing. Here, we ask whether the brain engages distinct neurocognitive mechanisms in response to inputs that fulfill versus violate strong predictions at different levels of representation during language comprehension. Participants read three-sentence scenarios in which the third sentence constrained for a broad event structure, for example, {Agent caution animate-Patient}. High constraint contexts additionally constrained for a specific event/lexical item, for example, a two-sentence context about a beach, lifeguards, and sharks constrained for the event, {Lifeguards cautioned Swimmers}, and the specific lexical item swimmers. Low constraint contexts did not constrain for any specific event/lexical item. We measured ERPs on critical nouns that fulfilled and/or violated each of these constraints. We found clear, dissociable effects to fulfilled semantic predictions (a reduced N400), to event/lexical prediction violations (an increased late frontal positivity), and to event structure/animacy prediction violations (an increased late posterior positivity/P600). We argue that the late frontal positivity reflects a large change in activity associated with successfully updating the comprehender's current situation model with new unpredicted information. We suggest that the late posterior positivity/P600 is triggered when the comprehender detects a conflict between the input and her model of the communicator and communicative environment. This leads to an initial failure to incorporate the unpredicted input into the situation model, which may be followed by second-pass attempts to make sense of the discourse through reanalysis, repair, or reinterpretation. Together, these findings provide strong evidence that confirmed and violated predictions at different levels of representation manifest as distinct spatiotemporal neural signatures.