[The EEG N400 component as a marker of language acquisition and processing in cochlear implant users]. / Die N400-Komponente im EEG als Marker für Spracherwerb und Wortverarbeitung nach CI-Versorgung.

Language processing can be measured objectively using late components in the evoked brain potential. The most established component in this area of research is the N400 component, a negativity that peaks at about 400 ms after stimulus onset with a centro-parietal maximum. It reflects semantic processing. Its presence, as well as its temporal and quantitative expression, allows to conclude about the quality of processing. It is therefore suitable for measuring speech comprehension in special populations, such as cochlear implant (CI) users. The following is an overview of the use of the N400 component as a tool for studying language processes in CI users. We present studies with adult CI users, where the N400 reflects the quality of speech comprehension with the new hearing device and we present studies with children where the emergence of the N400 component reflects the acquisition of their very first vocabulary.

Lexical skills and gesture use: A comparison between expressive and receptive/expressive late talkers.

BACKGROUND: Studies on late talkers (LTs) highlighted their heterogeneity and the relevance of describing different communicative profiles. AIMS: To examine lexical skills and gesture use in expressive (E-LTs) vs. receptive-expressive (R/E-LTs) LTs through a structured task. METHODS AND PROCEDURES: Forty-six 30-month-old screened LTs were distinguished into E-LTs (n= 35) and R/E-LTs (n= 11) according to their receptive skills. Lexical skills and gesture use were assessed with a Picture Naming Game by coding answer accuracy (correct, incorrect, no response), modality of expression (spoken, spoken-gestural, gestural), type of gestures (deictic, representational), and spoken-gestural answers' semantic relationship (complementary, equivalent, supplementary). OUTCOMES AND RESULTS: R/E-LTs showed lower scores than E-LTs for noun and predicate comprehension with fewer correct answers, and production with fewer correct and incorrect answers, and more no responses. R/E-LTs also exhibited lower scores in spoken answers, representational gestures, and equivalent spoken-gestural answers for noun production and in all spoken and gestural answers for predicate production. CONCLUSIONS AND IMPLICATIONS: Findings highlighted more impaired receptive and expressive lexical skills and lower gesture use in R/E-LTs compared to E-LTs, underlying the relevance of assessing both lexical and gestural skills through a structured task, besides parental questionnaires and developmental scales, to describe LTs' communicative profiles.

Conversational production and comprehension: fMRI-evidence reminiscent of but deviant from the classical Broca-Wernicke model.

A key question in research on the neurobiology of language is to which extent the language production and comprehension systems share neural infrastructure, but this question has not been addressed in the context of conversation. We utilized a public fMRI dataset where 24 participants engaged in unscripted conversations with a confederate outside the scanner, via an audio-video link. We provide evidence indicating that the two systems share neural infrastructure in the left-lateralized perisylvian language network, but diverge regarding the level of activation in regions within the network. Activity in the left inferior frontal gyrus was stronger in production compared to comprehension, while comprehension showed stronger recruitment of the left anterior middle temporal gyrus and superior temporal sulcus, compared to production. Although our results are reminiscent of the classical Broca-Wernicke model, the anterior (rather than posterior) temporal activation is a notable difference from that model. This is one of the findings that may be a consequence of the conversational setting, another being that conversational production activated what we interpret as higher-level socio-pragmatic processes. In conclusion, we present evidence for partial overlap and functional asymmetry of the neural infrastructure of production and comprehension, in the above-mentioned frontal vs temporal regions during conversation.

Neural evidence for referential understanding of object words in dogs.

Using words to refer to objects in the environment is a core feature of the human language faculty. Referential understanding assumes the formation of mental representations of these words.1,2 Such understanding of object words has not yet been demonstrated as a general capacity in any non-human species,3 despite multiple behavior-based case reports.4,5,6,7,8,9,10 In human event-related potential (ERP) studies, object word knowledge is typically tested using the semantic violation paradigm, where words are presented either with their referent (match) or another object (mismatch).11,12 Such mismatch elicits an N400 effect, a well-established neural correlate of semantic processing.12,13 Reports of preverbal infant N400 evoked by semantic violations14 assert the use of this paradigm to probe mental representations of object words in nonverbal populations. Here, measuring dogs' (Canis familiaris) ERPs to objects primed with matching or mismatching object words, we found a mismatch effect at a frontal electrode, with a latency (206-606 ms) comparable to the human N400. A greater difference for words that dogs knew better, according to owner reports, further supported a semantic interpretation of this effect. Semantic expectations emerged irrespective of vocabulary size, demonstrating the prevalence of referential understanding in dogs. These results provide the first neural evidence for object word knowledge in a non-human animal. VIDEO ABSTRACT.

Neurophysiological signatures of prediction in language: A critical review of anticipatory negativities.

Recent event-related potential (ERP) studies in language comprehension converge in finding anticipatory negativities preceding words or word segments that can be pre-activated based on either sentence contexts or phonological cues. We review these findings from different paradigms in the light of evidence from other cognitive domains in which slow negative potentials have long been associated with anticipatory processes and discuss their potential underlying mechanisms. We propose that this family of anticipatory negativities captures common mechanisms associated with the pre-activation of linguistic information both within words and within sentences. Future studies could utilize these anticipatory negativities in combination with other, well-established ERPs, to simultaneously track prediction-related processes emerging at different time intervals (before and after the perception of pre-activated input) and with distinct time courses (shorter-lived and longer-lived cognitive operations).

Alpha and Beta Oscillations Differentially Support Word Production in a Rule-Switching Task.

Research into the role of brain oscillations in basic perceptual and cognitive functions has suggested that the alpha rhythm reflects functional inhibition while the beta rhythm reflects neural ensemble (re)activation. However, little is known regarding the generalization of these proposed fundamental operations to linguistic processes, such as speech comprehension and production. Here, we recorded magnetoencephalography in participants performing a novel rule-switching paradigm. Specifically, Dutch native speakers had to produce an alternative exemplar from the same category or a feature of a given target word embedded in spoken sentences (e.g., for the word "tuna", an exemplar from the same category-"seafood"-would be "shrimp", and a feature would be "pink"). A cue indicated the task rule-exemplar or feature-either before (pre-cue) or after (retro-cue) listening to the sentence. Alpha power during the working memory delay was lower for retro-cue compared with that for pre-cue in the left hemispheric language-related regions. Critically, alpha power negatively correlated with reaction times, suggestive of alpha facilitating task performance by regulating inhibition in regions linked to lexical retrieval. Furthermore, we observed a different spatiotemporal pattern of beta activity for exemplars versus features in the right temporoparietal regions, in line with the proposed role of beta in recruiting neural networks for the encoding of distinct categories. Overall, our study provides evidence for the generalizability of the role of alpha and beta oscillations from perceptual to more "complex, linguistic processes" and offers a novel task to investigate links between rule-switching, working memory, and word production.

People constrain their semantic associations when talking to both friends and strangers.

During conversations, people face a trade-off between establishing understanding and making interesting and unique contributions. How do people balance this when deciding which concepts to reference, and does it matter how well they know their conversation partner? In the present work, participants made stream-of-consciousness word associations either with a partner or alone-simplified versions of dialogue and monologue. Participants made semantically narrower and more predictable word associations with a stranger than alone (Study 1), suggesting that they constrain their associations to establish mutual understanding. Increasing closeness (Study 2) or having a prior relationship (Study 3) did not moderate this effect. Thus, even during a task that does not depend on establishing mutual understanding, people sacrifice being interesting for the sake of being understood. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Contribution of the language network to the comprehension of Python programming code.

Does the perisylvian language network contribute to comprehension of programming languages, like Python? Univariate neuroimaging studies find high responses to code in fronto-parietal executive areas but not in fronto-temporal language areas, suggesting the language network does little. We used multivariate-pattern-analysis to test whether the language network encodes Python functions. Python programmers read functions while undergoing fMRI. A linear SVM decoded for-loops from if-conditionals based on activity in lateral temporal (LT) language cortex. In searchlight analysis, decoding accuracy was higher in LT language cortex than anywhere else. Follow up analysis showed that decoding was not driven by presence of different words across functions, "for" vs "if," but by compositional program properties. Finally, univariate responses to code peaked earlier in LT language-cortex than in the fronto-parietal network. We propose that the language system forms initial "surface meaning" representations of programs, which input to the reasoning network for processing of algorithms.

Tracking the neural codes for words and phrases during semantic composition, working-memory storage, and retrieval.

The ability to compose successive words into a meaningful phrase is a characteristic feature of human cognition, yet its neural mechanisms remain incompletely understood. Here, we analyze the cortical mechanisms of semantic composition using magnetoencephalography (MEG) while participants read one-word, two-word, and five-word noun phrases and compared them with a subsequent image. Decoding of MEG signals revealed three processing stages. During phrase comprehension, the representation of individual words was sustained for a variable duration depending on phrasal context. During the delay period, the word code was replaced by a working-memory code whose activation increased with semantic complexity. Finally, the speed and accuracy of retrieval depended on semantic complexity and was faster for surface than for deep semantic properties. In conclusion, we propose that the brain initially encodes phrases using factorized dimensions for successive words but later compresses them in working memory and requires a period of decompression to access them.

Pragmatic Skills in Late Adulthood.

Research investigating pragmatic abilities in healthy aging suggests that both production and comprehension might be compromised; however, it is not clear how pragmatic abilities evolve in late adulthood, as well as when difficulties are more likely to arise. The aim of this study is to investigate the decline of pragmatic skills in aging, and to explore what cognitive and demographic factors support pragmatic competence. We assessed pragmatic production skills, including discourse abilities such as speech, informativeness, information flow, paralinguistic aspects, as well as the ability to produce informative descriptions of pictures, and pragmatic comprehension skills, which encompassed the ability to understand discourse and the main aspects of a narrative text, to infer non-literal meanings and to comprehend verbal humor in a group of elderly individuals and in a sample of younger participants. Moreover, specific cognitive functions (short-term memory, verbal and visuospatial working memory, inhibition Theory of Mind, and Cognitive Reserve) were assessed in both groups. Pragmatic difficulties seem to occur in late adulthood, likely around 70 years, and emerge more prominently when participants are asked to understand verbal humor. Age was the only predictor of general pragmatic performance in a sample of cognitively unimpaired older adults; conversely, when elderly individuals with less intact inhibitory control are considered, a general role of inhibition emerged, in addition to working memory and ToM in specific tasks.

Do accent and input modality modulate processing of language switches in bilingual language comprehension?

We examined how bilinguals process language switches between their first (L1) and second language (L2). Language switching costs (slower responses to language switch than nonswitch trials) appear to arise more systematically in production than in comprehension, possibly because the latter context might sometimes elicit less language coactivation (Declerck et al., 2019). This might reduce language competition and in turn the need for bilinguals to apply language control when processing language switches. Yet even in comprehension, language coactivation may vary depending on variables such as the accent of the speaker (e.g., whether the L2 words are pronounced with an L1 or L2 accent) and input modality (spoken or written). In three experiments conducted during 2021-2022, we tested how unbalanced Mandarin-English bilinguals processed language switches during comprehension and the potential influence of a speaker's accent and input modality. Overall, across settings, participants experienced significant language switching costs. In some conditions, switching costs were larger to L1-Mandarin than to L2-English, an asymmetry consistent with the participants' dominance in L1-Mandarin and the application of language control. However, manipulating accent and input modality did not influence language switches, suggesting they did not impact language coactivation sufficiently to modulate language control. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Individual word representations dissociate from linguistic context along a cortical unimodal to heteromodal gradient.

Language comprehension involves multiple hierarchical processing stages across time, space, and levels of representation. When processing a word, the sensory input is transformed into increasingly abstract representations that need to be integrated with the linguistic context. Thus, language comprehension involves both input-driven as well as context-dependent processes. While neuroimaging research has traditionally focused on mapping individual brain regions to the distinct underlying processes, recent studies indicate that whole-brain distributed patterns of cortical activation might be highly relevant for cognitive functions, including language. One such pattern, based on resting-state connectivity, is the 'principal cortical gradient', which dissociates sensory from heteromodal brain regions. The present study investigated the extent to which this gradient provides an organizational principle underlying language function, using a multimodal neuroimaging dataset of functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) recordings from 102 participants during sentence reading. We found that the brain response to individual representations of a word (word length, orthographic distance, and word frequency), which reflect visual; orthographic; and lexical properties, gradually increases towards the sensory end of the gradient. Although these properties showed opposite effect directions in fMRI and MEG, their association with the sensory end of the gradient was consistent across both neuroimaging modalities. In contrast, MEG revealed that properties reflecting a word's relation to its linguistic context (semantic similarity and position within the sentence) involve the heteromodal end of the gradient to a stronger extent. This dissociation between individual word and contextual properties was stable across earlier and later time windows during word presentation, indicating interactive processing of word representations and linguistic context at opposing ends of the principal gradient. To conclude, our findings indicate that the principal gradient underlies the organization of a range of linguistic representations while supporting a gradual distinction between context-independent and context-dependent representations. Furthermore, the gradient reveals convergent patterns across neuroimaging modalities (similar location along the gradient) in the presence of divergent responses (opposite effect directions).

Acute stress negatively impacts on-task behavior and lecture comprehension.

Acute stress has been shown to disrupt cognitive and learning processes. The present study examined the effects of acute stress on mind wandering during a lecture and subsequent lecture comprehension in young adults. Forty participants were randomized to acute stress induction via the Trier Social Stress Test or rest prior to watching a twenty-minute video lecture with embedded mind wandering probes, followed by a lecture comprehension assessment. Stress responses were assessed via heart rate, blood pressure, salivary cortisol, and state anxiety. Individuals exposed to acute stress endorsed greater mind wandering at the first checkpoint and lower lecture comprehension scores. Moreover, state anxiety post stress was positively associated with mind wandering at the first and second checkpoint and negatively associated with lecture comprehension. Only mind wandering at the third checkpoint was negatively correlated with overall lecture comprehension. Taken together, these data suggest that acute stress, mind wandering, and lecture comprehension are inextricably linked.

Driving and suppressing the human language network using large language models.

Transformer models such as GPT generate human-like language and are predictive of human brain responses to language. Here, using functional-MRI-measured brain responses to 1,000 diverse sentences, we first show that a GPT-based encoding model can predict the magnitude of the brain response associated with each sentence. We then use the model to identify new sentences that are predicted to drive or suppress responses in the human language network. We show that these model-selected novel sentences indeed strongly drive and suppress the activity of human language areas in new individuals. A systematic analysis of the model-selected sentences reveals that surprisal and well-formedness of linguistic input are key determinants of response strength in the language network. These results establish the ability of neural network models to not only mimic human language but also non-invasively control neural activity in higher-level cortical areas, such as the language network.

Cognition-Emotion Interaction during L2 Sentence Comprehension: The Correlation of ERP and GSR Responses to Sense Combinations.

This study mainly examined the role of the combination of three senses (i.e., auditory, visual, and tactile) and five senses (i.e., auditory, visual, tactile, olfactory, and gustatory) in the correlation between electrophysiological and electrodermal responses underlying second language (L2) sentence comprehension. Forty subjects did two acceptability judgment tasks, encompassing congruent and semantically/pragmatically incongruent sentences. The event-related potential (ERP) and galvanic skin response (GSR) data for both the target and final words of the sentences were collected and analyzed. The results revealed that there is an interaction between cognitive and emotional responses in both semantically and pragmatically incongruent sentences, yet the timing of the interaction is longer in sentences with pragmatic incongruity due to their complexity. Based on the ERP and GSR correlation results, it was further found that the five-sense combination approach improves L2 sentence comprehension and interest in learning materials yet reduces the level of excitement or arousal. While this approach might be beneficial for some learners, it might be detrimental for those in favor of stimulating learning environments.

The influence of sentence focus on motor system activity in language comprehension and its temporal dynamics: Preliminary evidence from sEMG.

Previous research has shown that individual experiences and experimental tasks can influence the occurrence of mental simulation during sentence comprehension. However, little research has focused on the effect of sentence focus on mental simulation and its temporal dynamics. Sentence focus refers to the hierarchical structure of information within a sentence, where focused information represents the most prominent and essential information. In contrast, nonfocused information provides a background for the focused information. The present study investigated whether sentence focus would affect the activity of the motor system in language comprehension and at which stage the effect of sentence focus occurred. We measured spontaneous arm muscle electrical activity by surface electromyography (sEMG) while participants read action-focused, nonaction-focused, and control sentences. We observed greater spontaneous muscle electrical activity in the flexor common muscle of the fingers when participants read action-focused sentences compared to nonaction-focused and control sentences. Additionally, there was an interactive trend between sentence type and time, spontaneous muscle electrical activity while reading action-focused sentences was observed in both early (1 ms to 300 ms after the presentation of the action phrase) and late time windows (901 ms to 1500 ms after the action phrase). The findings suggest that the motor system exhibits flexible engagement during language comprehension and the impact of sentence focus on motor system activity may be throughout both the lexical-semantic retrieval and sentence-meaning integration stages.

Predictive Brain Activity Shows Congruent Semantic Specificity in Language Comprehension and Production.

Sentence fragments strongly predicting a specific subsequent meaningful word elicit larger preword slow waves, prediction potentials (PPs), than unpredictive contexts. To test the current predictive processing models, 128-channel EEG data were collected from both sexes to examine whether (1) different semantic PPs are elicited in language comprehension and production and (2) whether these PPs originate from the same specific "prediction area(s)" or rather from widely distributed category-specific neuronal circuits reflecting the meaning of the predicted item. Slow waves larger after predictable than unpredictable contexts were present both before subjects heard the sentence-final word in the comprehension experiment and before they pronounced the sentence-final word in the production experiment. Crucially, cortical sources underlying the semantic PP were distributed across several cortical areas and differed between the semantic categories of the expected words. In both production and comprehension, the anticipation of animal words was reflected by sources in posterior visual areas, whereas predictable tool words were preceded by sources in the frontocentral sensorimotor cortex. For both modalities, PP size increased with higher cloze probability, thus further confirming that it reflects semantic prediction, and with shorter latencies with which participants completed sentence fragments. These results sit well with theories viewing distributed semantic category-specific circuits as the mechanistic basis of semantic prediction in the two modalities.

Effects of age on the time course of syntactic priming in Chinese sentence production: an ERP study.

Using a syntactic priming task, we investigated the time course of syntactic encoding in Chinese sentence production and compared encoding patterns between younger and older adults. Participants alternately read sentence descriptions and overtly described pictures, while event-related potentials (ERPs) were recorded. We manipulated the abstract prime structure (active or passive) as well as the lexical overlap of the prime and the target (verb overlap or no overlap). The syntactic choice results replicated classical abstract priming and lexical boost effects in both younger and older adults. However, when production latency was taken into account, the speed benefit from syntactic repetition differed between the two age groups. Meanwhile, preferred priming facilitated production in both age groups, whereas nonpreferred priming inhibited production in the older group. For electroencephalography, an earlier effect of syntactic repetition and a later effect of lexical overlap showed a two-stage pattern of syntactic encoding. Older adults also showed a more delayed and interactive encoding pattern than younger adults, indicating a greater reliance on lexical information. These results are illustrative of the two-stage competition and residual activation models.

Hand Gestures Have Predictive Potential During Conversation: An Investigation of the Timing of Gestures in Relation to Speech.

During face-to-face conversation, transitions between speaker turns are incredibly fast. These fast turn exchanges seem to involve next speakers predicting upcoming semantic information, such that next turn planning can begin before a current turn is complete. Given that face-to-face conversation also involves the use of communicative bodily signals, an important question is how bodily signals such as co-speech hand gestures play into these processes of prediction and fast responding. In this corpus study, we found that hand gestures that depict or refer to semantic information started before the corresponding information in speech, which held both for the onset of the gesture as a whole, as well as the onset of the stroke (the most meaningful part of the gesture). This early timing potentially allows listeners to use the gestural information to predict the corresponding semantic information to be conveyed in speech. Moreover, we provided further evidence that questions with gestures got faster responses than questions without gestures. However, we found no evidence for the idea that how much a gesture precedes its lexical affiliate (i.e., its predictive potential) relates to how fast responses were given. The findings presented here highlight the importance of the temporal relation between speech and gesture and help to illuminate the potential mechanisms underpinning multimodal language processing during face-to-face conversation.

Mental Simulations and Action Language Are Impaired in Individuals with Aphantasia.

Action reading is thought to engage motor simulations, such as those involved during the generation of mental motor images. These simulations would yield modulations in activity of motor-related cortical regions and contribute to action language comprehension. To test these ideas, we measured corticospinal excitability during action reading, and reading comprehension ability, in individuals with normal and impaired imagery (i.e., phantasia and aphantasia, respectively). Thirty-four participants (17 phantasic and 17 aphantasic) were asked to read manual action sentences. By means of TMS, we triggered motor-evoked potentials in the target right index finger. Motor-evoked potential amplitude, a marker of corticospinal excitability, increased during action reading relative to rest for phantasic individuals, but not for aphantasic individuals. This result provides neurophysiological evidence that individuals living with aphantasia present a real neurophysiological deficit in motor system engagement during action reading. Furthermore, deep-level reading comprehension ability was impaired in individuals with aphantasia, who had difficulty selecting words that best fit the context of sentences. Altogether, these findings support the idea that motor simulations, along with the activation within the motor system, contribute to action language comprehension.