Journal of Neurolinguistics最新文献

Previous research has documented the impact of bilingualism on the functional connectivity (FC) of brain networks responsible for processing of two languages during a resting-state brain activity. However, the BOLD signal modulation during task-evoked neural activity remains unclear. To address this question we focused on language-related differences of fMRI-based FC of bilingual brains during morphosyntactic processing in L1 and L2 among balanced L1-Turkish-L2-Persian bilinguals who had learnt L2 at age 7. The task required grammaticality judgements to alternating L1-L2 sentences. In our previous study on the present dataset, we had demonstrated changes in BOLD activation in the Pars opercularis (PO), posterior Superior Temporal Gyrus (pSTG), Planum Temporale (PT), and Supplementary Motor Area (SMA), associated with auditory morphosyntactic processing. In the present reanalysis of these data we focused on FC within and between the language network and the control network. Regions of interest were based on the syntax- and control-specific regions activated by the task. Our findings confirm the FC between the syntax-specific regions PO and pSTG within the language network. The FC between these areas in the processing of morphosyntax turned to be quite similar for L1 and L2, reflecting the high competences of our balanced bilinguals in both languages. In the control network, direct FCs were found in two key areas of the PT and SMA (i.e. left PT to right PT and left PT to left SMA), supporting the view that these areas subserve control operations when bilinguals perceive and process spoken language. Remarkably, inter- and intra-hemispheric connectivities in the control network were indistinguishable for L1 and L2. Regarding intra-network results, although increased FCs were observed in L1 for the left PO-PT neurocircuit and in L2 for the pSTG-PT neurocircuit, none of them significantly interacted with grammaticality. Overall, these results suggest that being balanced bilingual with age of acquisition at 7 years appears to be associated with similarities of FC between syntax processing-related and input- and output-related brain networks. Considering that previous resting state studies had not found evidence for the above-mentioned connections in bilinguals, the present results indicate the importance of task-driven reconfigurations on functional connections between brain networks.

Although researchers often rely on group-level fMRI results to draw conclusions about the neurobiology of language, doing so without accounting for the complexities of individual brains may reduce the validity of our findings. Furthermore, understanding brain organization in individuals is critically important for both basic science and clinical translation. To assess the state of single-subject language localization in the functional neuroimaging literature, we carried out a systematic review of studies published through April 2020. Out of 977 papers identified through our search, 121 met our inclusion criteria for reporting single-subject fMRI results (fMRI studies of language in adults that report task-based single-subject statistics). Of these, 20 papers reported using a single-subject test-retest analysis to assess reliability. Thus, we found that a relatively modest number of papers reporting single-subject results quantified single-subject reliability. These varied substantially in acquisition parameters, task design, and reliability measures, creating significant challenges for making comparisons across studies. Future endeavors to optimize the localization of language networks in individuals will benefit from the standardization and broader reporting of reliability metrics for different tasks and acquisition parameters.

We examined the auditory sentence processing of neurologically unimpaired listeners and individuals with aphasia on canonical sentence structures in real-time using a visual-world eye-tracking paradigm. The canonical sentence constructions contained multiple noun phrases and an unaccusative verb, the latter of which formed a long-distance dependency link between the unaccusative verb and its single argument (which was base generated in the object position and then displaced to the subject position). To explore the likelihood of similarity-based interference during the real time linking of the verb and the sentence's subject noun, we manipulated the animacy feature of the noun phrases (matched or mismatched). The study's objectives were to examine whether (a) reducing the similarity-based interference by mismatching animacy features would modulate the encoding and retrieval dynamics of noun phrases in real-time; and (b) whether individuals with aphasia would demonstrate on time sensitivity to this lexical-semantic cue. Results revealed a significant effect of this manipulation in individuals both with and without aphasia. In other words, the mismatch in the representational features of the noun phrases increased the distinctiveness of the unaccusative verb's subject target at the time of syntactic retrieval (verb offset) for individuals in both groups. Moreover, individuals with aphasia were shown to be sensitive to the lexical-semantic cue, even though they appeared to process it slower than unimpaired listeners. This study extends to the cue-based retrieval model by providing new insight on the real-time mechanisms underpinning sentence comprehension.

Previous studies on the neuro-cognition of language have provided a strong case for systematic inter-individual variability in event-related potentials (ERPs) evoked during language processing. In the present study, we aimed at extending this evidence to the processing of morphologically complex words. We focused on German plural forms and tested two types of morphological violations: overapplications of regular plural morphemes (‘regularizations’) and of irregular plural morphemes (‘irregularizations’). The group-level results showed a biphasic LAN-P600 response for regularizations, and a P600 for irregularizations. In line with previous reports, our analyses of inter-individual variability suggested that biphasic responses consisting of a negativity followed by a positivity are unlikely to exist at the individual level. Importantly, when analyzing the scalp distribution of ERPs elicited in participants supposed to show negativity-dominant responses, we found this to vary as a function of the type of morphological form: regularizations elicited a left-hemisphere response (LAN), while irregularizations a more widespread negativity (N400). Our results are consistent with dual-route accounts of morphological processing that distinguish between rule-based processing for regular inflection and memory retrieval for irregular inflection. At a more general level, our study shows that complementing group-level results with analyses of inter-individual variability can crucially contribute to a more detailed understanding of brain signatures of language.

We review epilepsy-related aphasias in connection with GRIN2A mutations, focusing on acquired childhood epileptic aphasias such as Landau-Kleffner syndrome (LKS). The spontaneous speech of children with LKS exhibits syntactically simplified utterances, severe word finding difficulties, and severe phonological paraphasias. Characterizing LKS as a neural dysrhythmia, we review how EEG abnormalities typically manifested during non-rapid eye movement (NREM) sleep as electrical status epilepticus are related to sleeping disorders partly caused by GRIN2A mutations. Expanding on speculations originally put forward by Landau & Kleffner, 1957, we explore how neural processes such as sharp-wave ripples, sleep spindles, slow oscillations, and their cross-frequency couplings are necessary for language-related processes which are perturbed in LKS, accounting in part for the linguistic profile of epileptic aphasias.

Processing deficits at the lexical level, such as delayed and reduced lexical activation, have been theorized as the source of breakdowns in syntactic operations and thus contribute to sentence comprehension deficits in individuals with aphasia (IWA). In the current study, we investigate the relationship between lexical and syntactic processing in object-relative sentences using eye-tracking while listening in IWA. We explore whether manipulating the time available to process a critical lexical item (the direct-object noun) when it is initially heard in a sentence has an immediate effect on lexical access as well as a downstream effect on syntactic processing. To achieve this aim, we use novel temporal manipulations to provide additional time for lexical processing to occur. In addition to exploring these temporal effects in IWA, we also seek to understand the effect that additional time has on sentence processing in neurotypical age-matched adults (AMC). We predict that the temporal manipulations designed to provide increased processing time for critical lexical items will 1) enhance lexical processing of the target noun, 2) facilitate syntactic integration, and 3) improve sentence comprehension for both IWA and AMC. We demonstrate that strengthening lexical processing via the addition of time can affect lexical processing and facilitate syntactic retrieval of the target noun and lead to enhanced interference resolution in both unimpaired and impaired systems. In aphasia, additional time can mitigate impairments in spreading activation thereby improving lexical access and reducing interference during downstream dependency linking. However, individuals with aphasia may require longer additions of time to fully realize these benefits.

In the present study we explore whether gender congruency between languages modulates bilinguals’ access to their second language words presented in isolation. We predicted that accessing L2 words that have a different gender across languages (gender-incongruent) would be more costly and require more effort than accessing same-gender words (gender-congruent) due to language co-activation, even when no access to L1 was required to perform the task. Additionally, we intended to shed some light into the mechanism underlying the gender congruency effect. To these aims, we compared the performance of Spanish native speakers with that of Italian-Spanish bilinguals (Italian native speakers) during a lexical decision task. The participants saw Spanish words that were gender-congruent and gender-incongruent between languages while event related potentials were recorded. Moreover, as an additional manipulation, we selected nouns that in both languages could be ambiguous or unambiguous. With the aim to examine whether the underlying mechanism is activation of multiple information during word processing, we focused on the N400 component, related with the effort to integrate lexical-semantic information: higher N400 amplitudes indicate greater effort. According to our prediction, Italian-Spanish bilinguals produced more errors and evoked larger N400 amplitudes when accessing gender-incongruent than gender-congruent words, while no differences appeared for Spanish native speakers between conditions. These results indicate that gender-incongruent words are harder to integrate compared with gender-congruent words, and that bilinguals automatically activate the grammatical gender of both languages during L2 language comprehension. Nevertheless, the results do not seem to support the assumption of a similar mechanism responsible for the gender congruency and the ambiguity effects. In short, the gender-congruency effect seems to originate due to activation of multiple information at the lexical level which generates difficulties to integrate at the semantic level during word access.

This study investigates the parsing of Italian Wh-questions of the Which-N type. The extraction site could be either the subject or the object noun phrase. The verb following the Which-noun was either a singular or a plural form, immediately disambiguating the Which-N argument role through verb agreement. Reading time on the verb and on the post-verbal noun phrase were significantly shorter for the subject Wh-question than for the object Wh-question. Multi-channel ERP data showed increased P600 amplitudes for the object questions in response to the critical word on the left temporal lobe in the superior temporal gyrus. These findings are in line with the Minimal Chain Principle (De Vincenzi, 1991a) and provide further evidence for the hypothesis that the amplitude and duration of the P600 involve multi-dimensional processes controlling operations such as prediction, retrieval, revising, and structure-building operations needed for assembly (and disassembly) of syntactic relations.

The neural substrates of syntactic movements have been heavily investigated; however, little attention was paid to the fact that there was a cross-linguistic preference for filler-before-gap (filler-first) to gap-before-filler (gap-first) structures in subject-verb-object (SVO) languages. This fMRI study aimed to explore whether there was a cognitive basis for such a preference. Different filler-gap orders resulting from various syntactic movements were tested in Chinese: topicalization (filler-first) and relativization (gap-first, including subject and object relative clauses). The data showed that gap-first vs. filler-first contrasts activated the left anterior temporal gyrus (L-ATL) and sometimes the left thalamus. We argued that the L-ATL (and the left thalamus) was recruited because deeper semantic retrieval was performed on the verb to facilitate its merge with the gap for thematic role assignment. Our results provided a possible cognitive explanation for the preference for filler-first to gap-first structures in SVO languages.

Human language is proposed to be hierarchically constructed according to syntactic information. Studies on languages with overt morphosyntactic markers (e.g., German) have found a key frontotemporal syntactic network that includes Broca's area (Brodmann Area, BA 44/45) and the posterior temporal cortex (pTC). Whether this syntactic network is language-general is still unspecified. Mandarin Chinese is a suggestive empirical test case, lacking morphosyntax and relying heavily on function words to guide syntactic hierarchy construction. By developing the jabberwocky sentence paradigm, we created sets of visually-presented Chinese structures formed by function words and pseudo-words (the structure condition), and contrasted the structures with comparable word lists (the word-list condition) in healthy Chinese-speaking adults in a functional magnetic resonance imaging (fMRI) experiment. Participants were required to identify the syntactic category of each structure by merging its constituents into syntactic hierarchies, guided by function words. Compared with the word-list condition, the structure condition (a) elicited higher involvement of left BA 44, and (b) recruited a language-general syntactic network as revealed by the effective connectivity between BA 44, precentral gyrus, and pTC. These findings specified the neural basis for Chinese syntax and further corroborated the unique human language faculty across languages in a neurobiologically ubiquitous fashion.