Electrophysiological dynamics of Chinese phonology during visual word recognition in Chinese-English bilinguals

Silent word reading leads to the activation of orthographic (spelling), meaning, as well as phonological (sound) information. For bilinguals, native language information can also be activated automatically when they read words in their second language. For example, when Chinese-English bilinguals read words in their second language (English), the phonology of the Chinese translations is automatically activated. Chinese phonology, however, consists of consonants and vowels (segmental) and tonal information. To what extent these two aspects of Chinese phonology are activated is yet unclear. Here, we used behavioural measures, event-related potentials and oscillatory EEG to investigate Chinese segmental and tonal activation during word recognition. Evidence of Chinese segmental activation was found when bilinguals read English words (faster responses, reduced N400, gamma-band power reduction) and when they read Chinese words (increased LPC, gamma-band power reduction). In contrast, evidence for Chinese tonal activation was only found when bilinguals read Chinese words (gamma-band power increase). Together, our converging behavioural and electrophysiological evidence indicates that Chinese segmental information is activated during English word reading, whereas both segmental and tonal information are activated during Chinese word reading. Importantly, gamma-band oscillations are modulated differently by tonal and segmental activation, suggesting independent processing of Chinese tones and segments

The Bilingual Lexicon, Back and Forth: Electrophysiological Signatures of Translation Asymmetry

Available online 2 December 2021Mainstream theories of first and second language (L1, L2) processing in bilinguals are crucially informed by word translation research. A core finding is the translation asymmetry effect, typified by slower performance in forward translation (FT, from L1 into L2) than in backward translation (BT, from L2 into L1). Yet, few studies have explored its neural bases and none has employed (de)synchronization measures, precluding the integration of bilingual memory models with neural (de)coupling accounts of word processing. Here, 27 proficient Spanish-English bilinguals engaged in FT and BT of single words as we obtained high-density EEG recordings to perform cluster-based oscillatory and non-linear functional connectivity analyses. Relative to BT, FT yielded slower responses, higher frontal theta (4–7 Hz) power in an early window (0–300 ms), reduced centro-posterior lower-beta (14–20 Hz) and centro-frontal upper-beta (21–30 Hz) power in a later window (300–600 ms), and lower fronto-parietal connectivity below 10 Hz in the early window. Also, the greater the behavioral difference between FT and BT, the greater the power of the early theta cluster for FT over BT. These results reveal key (de)coupling dynamics underlying translation asymmetry, offering frequency-specific constraints for leading models of bilingual lexical processing.This work was supported by CONICET and FONCYT-PICT [grant numbers 2017-1818, 2017-1820]. Agustín Ibáñez is supported by grants of the Alzheimer’s Association GBHI ALZ UK-20-639295; Takeda CW2680521; ANID/FONDECYT Regular (1210195); ANID/FONDAP 15150012, Sistema General de Regalías (BPIN2018000100059), Universidad del Valle (CI 5316), and the Multi-Partner Consortium to Expand Dementia Research in Latin America (ReDLat), funded by the National Institutes of Aging (NIA) of the National Institutes of Health (NIH) under award number R01AG057234, an Alzheimer’s Association grant (SG-20-725707-ReDLat), the Rainwater Foundation, and the Global Brain Health Institute. Adolfo García is an Atlantic Fellow at the Global Brain Health Institute (GBHI) and is supported with funding from GBHI, Alzheimer’s Association, and Alzheimer’s Society (Alzheimer’s Association GBHI ALZ UK-22-865742); ANID, FONDECYT Regular (1210176); and Programa Interdisciplinario de Investigación Experimental en Comunicación y Cognición (PIIECC), Facultad de Humanidades, USACH. The content is solely the responsibility of the authors and does not represent the official views of the National Institutes of Health, Alzheimer’s Association, Rainwater Charitable Foundation, or Global Brain Health Institute

Riding the (brain) waves! Using neural oscillations to inform bilingualism research

The study of the brains’ oscillatory activity has been a standard technique to gain insights into human neurocognition for a relatively long time. However, as a complementary analysis to ERPs, only very recently has it been utilized to study bilingualism and its neural underpinnings. Here, we provide a theoretical and methodological starter for scientists in the (psycho)linguistics and neurocognition of bilingualism field(s) to understand the bases and applications of this analytical tool. Towards this goal, we provide a description of the characteristics of the human neural (and its oscillatory) signal, followed by an in-depth description of various types of EEG oscillatory analyses, supplemented by figures and relevant examples. We then utilize the scant, yet emergent, literature on neural oscillations and bilingualism to highlight the potential of how analyzing neural oscillations can advance our understanding of the (psycho)linguistic and neurocognitive understanding of bilingualism

Comprehending Events on the Fly: Inhibition and Selection during Sentence Processing

In our everyday conversations we talk about how things or people change. Instantiations of objects in their different states need to be maintained during language comprehension for future selection of the relevant state, as in The chef will chop the onion. And then/but first, she will weigh the onion. Previous fMRI studies (Solomon et al, 2015) demonstrated that selecting between multiple competing representations of the same object token, such as the intact and the chopped onion, elicits increased activation in the brain area associated with conflict resolution -- left pVLPFC. When there is no cue to the earlier introduced object, as in The chef will chop/smell the onion. And then, she will weigh another onion, no retrieval cost is observed because none of the states is relevant. However, due to the poor temporal resolution of fMRI, it is difficult to make assumptions about the dynamics of this effect and where exactly in the sentence it occurs. To track this competition effect over time, dEEG was recorded as participants (N=23) read sentences presented to them word by word. Critical sentences were organized in a two-by-two design with degree of change and token reference being the two factors. A time-frequency analysis of EEG, synchronized from the onset of the final determiner phrase in the second sentence, revealed a significant increase in alpha (8-12 Hz) in sentences describing state change and referring back to the same token. This finding is consistent with literature relating alpha oscillations to cortical inhibitory processing and selection mechanisms

Electrophysiological dynamics of Chinese phonology during visual word recognition in Chinese-English bilinguals

Silent word reading leads to the activation of orthographic (spelling), meaning, as well as phonological (sound) information. For bilinguals, native language information can also be activated automatically when they read words in their second language. For example, when Chinese-English bilinguals read words in their second language (English), the phonology of the Chinese translations is automatically activated. Chinese phonology, however, consists of consonants and vowels (segmental) and tonal information. To what extent these two aspects of Chinese phonology are activated is yet unclear. Here, we used behavioural measures, event-related potentials and oscillatory EEG to investigate Chinese segmental and tonal activation during word recognition. Evidence of Chinese segmental activation was found when bilinguals read English words (faster responses, reduced N400, gamma-band power reduction) and when they read Chinese words (increased LPC, gamma-band power reduction). In contrast, evidence for Chinese tonal activation was only found when bilinguals read Chinese words (gamma-band power increase). Together, our converging behavioural and electrophysiological evidence indicates that Chinese segmental information is activated during English word reading, whereas both segmental and tonal information are activated during Chinese word reading. Importantly, gamma-band oscillations are modulated differently by tonal and segmental activation, suggesting independent processing of Chinese tones and segments

Is beta in agreement with the relatives? Using relative clause sentences to investigate MEG beta power dynamics during sentence comprehension.

There remains some debate about whether beta power effects observed during sentence comprehension reflect ongoing syntactic unification operations (beta-syntax hypothesis), or instead reflect maintenance or updating of the sentence-level representation (beta-maintenance hypothesis). In this study, we used magnetoencephalography to investigate beta power neural dynamics while participants read relative clause sentences that were initially ambiguous between a subject- or an object-relative reading. An additional condition included a grammatical violation at the disambiguation point in the relative clause sentences. The beta-maintenance hypothesis predicts a decrease in beta power at the disambiguation point for unexpected (and less preferred) object-relative clause sentences and grammatical violations, as both signal a need to update the sentence-level representation. While the beta-syntax hypothesis also predicts a beta power decrease for grammatical violations due to a disruption of syntactic unification operations, it instead predicts an increase in beta power for the object-relative clause condition because syntactic unification at the point of disambiguation becomes more demanding. We observed decreased beta power for both the agreement violation and object-relative clause conditions in typical left hemisphere language regions, which provides compelling support for the beta-maintenance hypothesis. Mid-frontal theta power effects were also present for grammatical violations and object-relative clause sentences, suggesting that violations and unexpected sentence interpretations are registered as conflicts by the brain's domain-general error detection system.</p

Is prediction necessary to understand language? Probably not.

Many psycholinguistic experiments suggest that prediction is an important characteristic of language processing. Some recent theoretical accounts in the cognitive sciences (e.g., Clark, 2013; Friston, 2010) and psycholinguistics (e.g., Dell & Chang, 2014) appear to suggest that prediction is even necessary to understand language. In the present opinion paper we evaluate this proposal. We first critically discuss several arguments that may appear to be in line with the notion that prediction is necessary for language processing. These arguments include that prediction provides a unified theoretical principle of the human mind and that it pervades cortical function. We discuss whether evidence of human abilities to detect statistical regularities is necessarily evidence for predictive processing and evaluate suggestions that prediction is necessary for language learning. Five arguments are then presented that question the claim that all language processing is predictive in nature. We point out that not all language users appear to predict language and that suboptimal input makes prediction often very challenging. Prediction, moreover, is strongly context-dependent and impeded by resource limitations. We also argue that it may be problematic that most experimental evidence for predictive language processing comes from 'prediction-encouraging' experimental set-ups. Finally, we discuss possible ways that may lead to a further resolution of this debate. We conclude that languages can be learned and understood in the absence of prediction. Claims that all language processing is predictive in nature are premature

Dynamic semantic cognition : Characterising coherent and controlled conceptual retrieval through time using magnetoencephalography and chronometric transcranial magnetic stimulation

Distinct neural processes are thought to support the retrieval of semantic information that is (i) coherent with strongly-encoded aspects of knowledge, and (ii) non-dominant yet relevant for the current task or context. While the brain regions that support readily coherent and more controlled patterns of semantic retrieval are relatively well-characterised, the temporal dynamics of these processes are not well-understood. This study used magnetoencephalography (MEG) and dual-pulse chronometric transcranial magnetic stimulation (cTMS) in two separate experiments to examine temporal dynamics during the retrieval of strong and weak associations. MEG results revealed a dissociation within left temporal cortex: anterior temporal lobe (ATL) showed greater oscillatory response for strong than weak associations, while posterior middle temporal gyrus (pMTG) showed the reverse pattern. Left inferior frontal gyrus (IFG), a site associated with semantic control and retrieval, showed both patterns at different time points. In the cTMS experiment, stimulation of ATL at ∼150 msec disrupted the efficient retrieval of strong associations, indicating a necessary role for ATL in coherent conceptual activations. Stimulation of pMTG at the onset of the second word disrupted the retrieval of weak associations, suggesting this site may maintain information about semantic context from the first word, allowing efficient engagement of semantic control. Together these studies provide converging evidence for a functional dissociation within the temporal lobe, across both tasks and time

Number Specification in L2 processing of Norwegian adult L2 English speakers: Time-frequency representation (TFR) analysis

This thesis investigates the processing of non-local agreement violations and whether they are affected by double marking from a determiner-number specification in Norwegian L2 speakers of English. We tested non-local subject-verb agreement, a mismatch between Norwegian and English, and the double marking on the number of the noun that is a common feature of the two languages by using online Grammaticality Judgement test (GJT) during EEG (electroencephalogram) recording. There were four conditions to test the participants’ sensitivity towards determiner number specification: (1) Grammatical unspecified, (2) ungrammatical unspecified, (3) grammatical specified, (4) ungrammatical specified. The EEG data were analyzed with TFRs (time-frequency references) to observe the changes in different frequency bands of neural oscillations. Behavioural and neural responses to the sentences were compared to understand the neural mechanisms regarding the interaction between non-local agreement violations and determiner-number specification. The results showed no evidence for an interaction between specificity and grammaticality. The specificity did not seem to affect participants’ judgment of the grammaticality. That is, we did not see any change in the theta band (4-8 Hz); however, a relative decrease in the activation for the ungrammatical items vs grammatical items in the alpha band (8-12 Hz) and a relative decrease in the activation for the number-specified items vs number-unspecified items in alpha bands (8-12 Hz) was observed. The alpha band reactivity observed during language comprehension does not necessarily reflect the linguistic analyses but the attention. Alpha band decrease is explained as the engagement of the additional attentional resources to explain a faulty representation. The results of the behavioural data showed that the participants were better when judging the grammatical sentences than the ungrammatical sentences, and the unspecified grammatical sentences were judged more accurately than the other three conditions. The findings of the current study suggest that the agreement violation in GJT led the participants to have increased attentional process demands as they needed to judge the mismatching property between their L1 Norwegian and L2 English

Decoding speech comprehension from continuous EEG recordings

Human language is a remarkable manifestation of our cognitive abilities which is unique to our species. It is key to communication, but also to our faculty of generating complex thoughts. We organise, conceptualise, and share ideas through language. Neuroscience has shed insightful lights on our understanding of how language is processed by the brain although the exact neural organisation, structural or functional, underpinning this processing remains poorly known. This project aims to employ new methodology to understand speech comprehension during naturalistic listening condition. One achievement of this thesis lies in bringing evidence towards putative predictive processing mechanisms for language comprehension and confront those with rule-based grammar processing. Namely, we looked on the one hand at cortical responses to information-theoretic measures that are relevant for predictive coding in the context of language processing and on the other hand to the response to syntactic tree structures. We successfully recorded responses to linguistic features from continuous EEG recordings during naturalistic speech listening. The use of ecologically valid stimuli allowed us to embed neural response in the context in which they naturally occur when hearing speech. This fostered the development of new analysis tools adapted for such experimental designs. Finally, we demonstrate the ability to decode comprehension from the EEG signals of participants with above-chance accuracy. This could be used as a better indicator of the severity and specificity of language disorders, and also to assess if a patient in a vegetative state understands speech without the need for any behavioural response. Hence a primary outcome is our contribution to the neurobiology of language comprehension. Furthermore, our results pave the way to the development of a new range of diagnostic tools to measure speech comprehension of patients with language impairment.Open Acces