To avoid post-neurosurgical language deficits, intraoperative mapping of the language function in the brain can be complemented with preoperative mapping with functional magnetic resonance imaging (fMRI). The validity of an fMRI “language localizer” paradigm crucially depends on the choice of an optimal language task and baseline condition. This study presents a new fMRI “language localizer” in Russian using overt sentence completion, a task that comprehensively engages the language function by involving both production and comprehension at the word and sentence level. The paradigm was validated in 18 neurologically healthy volunteers who participated in two scanning sessions, for estimating test–retest reliability. For the first time, two baseline conditions for the sentence completion task were compared. At the group level, the paradigm significantly activated both anterior and posterior language-related regions. Individual-level analysis showed that activation was elicited most consistently in the inferior frontal regions, followed by posterior temporal regions and the angular gyrus. Test–retest reliability of activation location, as measured by Dice coefficients, was moderate and thus comparable to previous studies. Test–retest reliability was higher in the frontal than temporo-parietal region and with the most liberal statistical thresholding compared to two more conservative thresholding methods. Lateralization indices were expectedly left-hemispheric, with greater lateralization in the frontal than temporo-parietal region, and showed moderate test-retest reliability. Finally, the pseudoword baseline elicited more extensive and more reliable activation, although the syllable baseline appears more feasible for future clinical use. Overall, the study demonstrated the validity and reliability of the sentence completion task for mapping the language function in the brain. The paradigm needs further validation in a clinical sample of neurosurgical patients. Additionally, the study contributes to general evidence on test–retest reliability of fMRI.
Ample evidence suggests that monolingual adults can successfully generate lexical and morphosyntactic predictions in reading and that correct predictions facilitate sentence comprehension. In this eye-tracking corpus reading study, we investigate whether the same is true for reading in heritage language. Specifically, we ask whether heritage speakers (HSs) of Russian are able to anticipate lexical and/or morphosyntactic information of the upcoming words in the sentence and whether they differ in the predictions from monolingual children and L2 learners. We are also interested in whether the literacy level (i.e., Russian literacy experience or reading fluency in English) influences lexical and morphosyntactic prediction. Our results indicate that HSs as well as other groups were able to anticipate the specific lexical item, and the ability was contingent on the Russian literacy experience and reading fluency in dominant English as evident in some of the early and late eye-tracking measures. Similar to children and L2 learners, the word class and the verb number predictability affected reading times in HSs, but HSs were the only group to anticipate the number of the upcoming noun. We discuss findings in respect to the utility account of the bilingual prediction and divergent attainment trajectory of the heritage language development.
The study presents the first systematic comparison of the global reading processes via scanpath analysis in Russian-speaking children with and without reading difficulties. First, we compared basic eye-movement characteristics in reading sentences in two groups of children in grades 1 to 5 (N = 72 in high risk of developmental dyslexia group and N = 72 in the control group). Next, using the scanpath method, we investigated which global reading processes these children adopt to read the entire sentence and how these processes differ between the groups. Finally, we were interested in the timeframe of the change in the global reading processes from the 1st to the 5th grades for both groups. We found that the main difference in word-level measures between groups was the reading speed reflected in fixation durations. However, the examination of the five identified global reading processes revealed qualitative similarities in reading patterns between groups. Children in the control group progressed quickly and by the 4th grade engaged in an adult-like fluent reading process. The high-risk group started with the beginner reading process, then similar to first graders in the control group, engaged mostly in the intermediate and upper-intermediate reading processes in 2nd to 4th grades. They reach the advanced process in the 5th grade, the same pattern preferred by the control group second graders. Overall, the scanpath analysis reveals that although there are quantitative differences in the word-level eye-tracking measures between groups, qualitatively children in the high-risk group read on par with typically developing peers but with a 3-year reading delay.
The purpose of the present research was to comprehensively assess the language abilities of Russian primary-school-aged children with Autism Spectrum Disorder (ASD), varying in non-verbal IQ, at all linguistic levels (phonology, lexicon, morphosyntax, and discourse) in production and comprehension. Yet, the influence of such non-language factors as chil-dren's age, the severity of autistic traits, and non-verbal IQ on language functioning was studied. Our results indicate a high variability of language skills in children with ASD (from normal to impaired) which is in line with the previous studies. Interestingly, the number of children with normal language abilities was related to the linguistic levels: according to more complex morphosyntax and discourse tests, fewer children with ASD were within the normal range unlike the results in simpler phonological and lexical tests. Importantly, we found that language abilities were best predicted by non-verbal IQ but were independent from age and the severity of autistic traits. The findings support the claim that formal language assessment of children with ASD needs to include all linguistic levels, from phonology to discourse, for helping speech-language therapists to choose an appropriate therapy target.
Background: Coherence is the quality which distinguishes discourse from a random collection of sentences. People with aphasia have been reported to produce less-coherent discourse than non-language-impaired speakers. It is largely unclear how coherence is established in natural language and what leads to its impairment in aphasia.
Aims: This paper presents a cross-methodological investigation on coherence in discourse of Russian native speakers with and without aphasia. The purpose of this study was to examine the connection between language impairments in aphasia and different aspects of discourse coherence in order to determine the linguistic mechanisms that could be involved in establishing and maintaining it.
Methods & Procedures: Coherence was operationalised as a combination of four aspects: informativeness, clarity, connectedness, and understandability. Twenty participants were asked to retell the content of a short movie. The retellings were annotated using Rhetorical Structure Theory (RST), a formalistic framework for discourse-structure analysis. Next, they were evaluated for coherence on a four-point scale by trained raters. The ratings were compared between groups. A classification analysis was performed to determine whether the ratings could be predicted based on the macrolinguistic variables collected from the RST annotations and several microlinguistic variables previously linked to coherence.
Results: Retellings produced by speakers with aphasia received lower ratings than those of control participants on all aspects of coherence. The results indicate that different combinations of microlinguistic and discourse-structure variables play a role in establishing each of the coherence aspects.
Conclusions: Our results provided supporting evidence on coherence impairment in aphasia. Perception of a discourse as more or less coherent was associated with both micro- and macrolinguistic variables, with different combinations of variables relevant for each of the aspects. Furthermore, we found that discourse structure plays an important role, especially for understandability. We speculate that pragmatic knowledge shared by interlocutors may boost coherence of aphasic discourse.
Unlike stroke, neurosurgical removal of left-hemisphere gliomas acts upon a reorganized language network and involves brain areas rarely damaged by stroke. We addressed whether this causes the profiles of neurosurgeryand stroke-induced language impairments to be distinct. K-means clustering of language assessment data (neurosurgery cohort: N = 88, stroke cohort: N = 95) identified similar profiles in both cohorts. But critically, a cluster of individuals with specific phonological deficits was only evident in the stroke but not in the neurosurgery cohort. Thus, phonological deficits are less clearly distinguished from other language deficits after glioma surgery compared to stroke. Furthermore, the correlations between language production and comprehension scores at different linguistic levels were more extensive in the neurosurgery than in the stroke cohort. Our findings suggest that neurosurgery-induced language impairments do not correspond to those caused by stroke, but rather manifest as a ‘moderate global aphasia’ – a generalized decline of language processing abilities.
Russia has rich theoretical and behavioral research traditions in neurolinguistics and neuropsychology, but at the beginning of the twenty-first century contemporary experimental research in these disciplines remained limited, leading to proliferation of non-evidence-based approaches in education, healthcare, and public beliefs. An academic response to this was the establishment of the Center for Language and Brain at the HSE University, Moscow, which focused on experimental psycho- and neurolinguistic research and related evidence-based practices. The Center has grown from a small group of young researchers to a large interdisciplinary unit that conducts cutting-edge research utilizing multi-site settings and novel structural and functional neuroimaging methods. The overarching aim of the Center's research is to promote scientifically grounded treatment of the language-brain relationship in the educational, clinical, and industry settings. Specifically, translational research at the Center is contributing to the advancement of clinical practice in Russia: from providing the first standardized aphasia language test to implementing protocols for intraoperative language mapping in neurosurgery departments across the country. Within research projects, a new generation of scientists is successfully being fostered, while a broader student audience is reached via courses taught by staff of the Center to students of different majors. Notable examples of public outreach programs at the Center are the Annual Summer Neurolinguistics School attracting hundreds of attendees from different countries each year, and community projects focused on raising awareness about aphasia. Together, these efforts aim to increase scientific knowledge in a multi-professional audience. In this paper, we will share our joint experiences in establishing, building, and promoting a neurolinguistics research center in Russia and the impact that this work has had on the broader public. We will delineate specific milestones of this journey and focus on the main pillars that have contributed to our progress: research, clinical work, teaching, and public outreach programs. We hope that this critical appraisal of our experiences can serve simultaneously as an inspiration and a practical guide for other groups developing research, clinical, and educational programs in different neuroscientific disciplines across the globe and aiming to improve the quality of the neuroscientific information available to the public.
Background: The human white matter pathway network is complex and of critical importance for functionality. Thus, learning and understanding white matter tract anatomy is important for the training of neuroscientists and neurosurgeons. The study aims to test and evaluate a new method for fiber dissection using augmented reality (AR) in a group which is experienced in cadaver white matter dissection courses and in vivo tractography.
Methods: Fifteen neurosurgeons, neurolinguists, and neuroscientists participated in this questionnaire-based study. We presented five cases of patients with left-sided perisylvian gliomas who underwent awake craniotomy. Diffusion tensor imaging fiber tracking (DTI FT) was performed and the language-related networks were visualized separated in different tracts by color. Participants were able to virtually dissect the prepared DTI FTs using a spatial computer and AR goggles. The application was evaluated through a questionnaire with answers from 0 (minimum) to 10 (maximum).
Results: Participants rated the overall experience of AR fiber dissection with a median of 8 points (mean ± standard deviation 8.5 ± 1.4). Usefulness for fiber dissection courses and education in general was rated with 8 (8.3 ± 1.4) and 8 (8.1 ± 1.5) points, respectively. Educational value was expected to be high for several target audiences (student: median 9, 8.6 ± 1.4; resident: 9, 8.5 ± 1.8; surgeon: 9, 8.2 ± 2.4; scientist: 8.5, 8.0 ± 2.4). Even clinical application of AR fiber dissection was expected to be of value with a median of 7 points (7.0 ± 2.5).
Conclusion: The present evaluation of this first application of AR for fiber dissection shows a throughout positive evaluation for educational purposes.
Visualization of functionally significant subcortical white matter fibers is needed in neurosurgical procedures in order to avoid damage to the language network during resection. In an effort to achieve this, positive cortical points revealed during preoperative language mapping with navigated transcranial magnetic stimulation (nTMS) can be employed as regions of interest (ROIs) for diffusion tensor imaging (DTI) fiber tracking. However, the effect that the use of different language tasks has on nTMS mapping and subsequent DTI-fiber tracking remains unexplored. The visualization of ventral stream tracts with an assumed lexico-semantic role may especially benefit from ROIs delivered by the lexico-semantically demanding verb task, Action Naming. In a first step, bihemispheric nTMS language mapping was administered in 18 healthy participants using the standard task Object Naming and the novel task Action Naming to trigger verbs in a small sentence context. Cortical areas in which nTMS induced language errors were identified as language-positive cortical sites. In a second step, nTMS-based DTI-fiber tracking was conducted using solely these language-positive points as ROIs. The ability of the two tasks’ ROIs to visualize the dorsal tracts Arcuate Fascicle and Superior Longitudinal Fascicle, the ventral tracts Inferior Longitudinal Fascicle, Uncinate Fascicle, and Inferior Fronto-Occipital Fascicle, the speech-articulatory Cortico-Nuclear Tract, and interhemispheric commissural fibers was compared in both hemispheres. In the left hemisphere, ROIs of Action Naming led to a significantly higher fraction of overall visualized tracts, specifically in the ventral stream’s Inferior Fronto-Occipital and Inferior Longitudinal Fascicle. No difference was found between tracking with Action Naming vs. Object Naming seeds for dorsal stream tracts, neither for the speech-articulatory tract nor the inter-hemispheric connections. While the two tasks appeared equally demanding for phonological-articulatory processes, ROI seeding through the task Action Naming seemed to better visualize lexico-semantic tracts in the ventral stream. This distinction was not evident in the right hemisphere. However, the distribution of tracts exposed was, overall, mirrored relative to those in the left hemisphere network. In presurgical practice, mapping and tracking of language pathways may profit from these findings and should consider inclusion of the Action Naming task, particularly for lesions in ventral subcortical regions.
Preoperative language mapping with navigated transcranial magnetic stimulation (nTMS) is currently based on the disruption of performance during object naming. The resulting cortical language maps, however, lack accuracy when compared to intraoperative mapping. The question arises whether nTMS results can be improved, when another language task is considered, involving verb retrieval in sentence context. Twenty healthy German speakers were tested with object naming and a novel action naming task during nTMS language mapping. Error rates and categories in both hemispheres were compared. Action naming showed a significantly higher error rate than object naming in both hemispheres. Error category comparison revealed that this discrepancy stems from more lexico-semantic errors during action naming, indicating lexico-semantic retrieval of the verb being more affected than noun retrieval. In an area-wise comparison, higher error rates surfaced in multiple right-hemisphere areas, but only trends in the left ventral postcentral gyrus and middle superior temporal gyrus. Hesitation errors contributed significantly to the error count, but did not dull the mapping results. Inclusion of action naming coupled with a detailed error analysis may be favorable for nTMS mapping and ultimately improve accuracy in preoperative planning. Moreover, the results stress the recruitment of both left- and right-hemispheric areas during naming.
White matter makes up about fifty percent of the human brain. Maturation of white matter accompanies biological development and undergoes the most dramatic changes during childhood and adolescence. Despite the advances in neuroimaging techniques, controversy concerning spatial, and temporal patterns of myelination, as well as the degree to which the microstructural characteristics of white matter can vary in a healthy brain as a function of age, gender and cognitive abilities still exists. In a selective review we describe methods of assessing myelination and evaluate effects of age and gender in nine major fiber tracts, highlighting their role in higher-order cognitive functions. Our findings suggests that myelination indices vary by age, fiber tract, and hemisphere. Effects of gender were also identified, although some attribute differences to methodological factors or social and learning opportunities. Findings point to further directions of research that will improve our understanding of the complex myelination- behavior relation across development that may have implications for educational and clinical practice.
Non-invasive brain stimulation (NIBS) techniques combined with behavioral speech/language therapies have recently been suggested as a promising method for language recovery in people with aphasia (PWA). Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are currently the most common types of NIBS for aphasia rehabilitation. In this study, we combined either rTMS or tDCS with a behavioral therapy approach, Verb Network Strengthening Treatment (VNeST), that has neither been used before in a Russian-speaking post-stroke population nor combined with any type of NIBS. In a case series study, we demonstrate the results of two groups of participants: 1) 4 PWA who received one daily session of VNeST preceded by 20-minutes of rTMS for 8-12 days; and 2) 4 PWA who received 2 sessions of VNeST a day, with the first 20 minutes of the first daily session combined with tDCS, for 10 days. We assessed the accuracy of action naming and sentence production and found a significant improvement in sentence production in the tDCS + VNeST group, while the other group did not show a significant improvement in these tasks. Interestingly, we found a correlation between improvement in sentence production and the number of sessions regardless of the stimulation type and another correlation between improvement in action naming and initial aphasia severity. This study is a first attempt to apply the combination of these techniques in Russian. Our preliminary findings prompt larger-scale research to study the potential of this method.
This study aimed at examining morphological processing mechanisms involved in lexical access across the lifespan in the morphologically complex Russian language. We conducted an unprimed lexical decision experiment using number-dominant nouns in participants of a wide age range (n = 190, 9–87 years old), analysing age as a continuous factor. Additionally, we tested whether morphological processing mechanisms are affected by a linguistic factor – the type of plural formation. The results revealed no age-related change in morphological processing mechanisms in Russian: the processing mechanisms were consistent with the dual-route models across the lifespan. This suggests that morphological processing mechanisms are stable across the lifespan even in a morphologically complex language like Russian. Null effects of the type of plural formation provide evidence in favour of a special status of citation forms.
Background: Abnormal language development in both expressive and receptive domains occurs in most children with Autism Spectrum Disorder (ASD), although the language deficit is not a core symptom of ASD. However, previous studies disagree on the difference in the degree of impairment between expressive and receptive language in ASD. Existing research has concentrated on vocabulary and ‘global expressive and receptive language’, often using parental reports for language assessment. Moreover, most of these studies have focused on toddlers and preschoolers with ASD, whereas data from school-aged children with ASD are very limited. At the same time, the age of children might account for the inconsistencies across publications on expressive-receptive language difference in children with ASD.
Aims: The goal of the study was to directly compare the expressive and receptive language abilities of Russian primary-school-aged children with ASD (7–11 years old) at the levels of vocabulary, morphosyntax, and discourse.
Methods: 82 children with ASD participated in language testing. We used tests from the Russian Child Language Assessment Battery in order to assess vocabulary, morphosyntax, and discourse in expressive and receptive domains.
Results: Our results revealed different expressive and receptive patterns, depending on the linguistic level and tests complexity. Importantly, we showed that children’s non-verbal IQ partly accounted for the difference between production and comprehension abilities.
Conclusions: The expressive-better-than-receptive pattern in language has been considered by some authors as the unique hallmark of ASD. However, several studies, including our own, show that this is not a universal characteristic of ASD. We also revealed that expressive and receptive language patterns differed depending on the linguistic level, children’s non-verbal IQ, and assessment tools.
This eye-tracking study establishes basic eye-movement benchmarks in heritage language (HL) Russian-speaking adults and adolescents of high (n = 21) and low proficiency (n = 27) who read sentences in Cyrillic and compares them with those of monolingual skilled adult readers, 8-year-old children and L2 learners. Eye-movement reading patterns of Heritage Speakers (HS) revealed longer mean fixation durations, lower skipping probability, and higher regressive saccade rates than monolingual adults. High-proficient HSs were more similar to monolingual children, while low-proficient HSs performed on par with L2 learners. Low-proficient HS differed from high-proficient HS in exhibiting lower skipping probabilities, higher fixation counts, and larger frequency effects. Taken together, our findings are consistent with the weaker links account of bilingual language processing as well as the divergent attainment theory of HL.
Background and objectives: We provide a case analysis for a 28-year-old, native Dutch-speaking lady who developed Foreign Accent Syndrome (FAS), a few weeks after falling down the staircase. In addition to FAS, which gave the impression she spoke with a German accent, German(-like) words and structures occurred. Speech symptoms were aggravated by increased stress, fatigue or emotional pressure, and this triggered jargon speech. It was hypothesized her FAS and jargon developed on a functional basis. Methods: In-depth analyses of the patient’s medical background, neuropsychological and neurolinguistic tests and psychodiagnostic exams were done. The patient participated in an fMRI experiment. In a syllable repetition paradigm, motor speech activations were compared to those of healthy individuals, to see whether they were altered, which would be expected in case of a neurological etiology.
Results: Medical history disclosed prior traumatic experiences for which she sought help, but no neurological incidents. Repeated neuropsychological and neurolinguistic tests showed deficits in recent memory and executive functioning. The patient demonstrated great difficulties with picture naming. Clinically, language switching and mixing as well as recurring jargon speech was found. Formal psychodiagnostic tests did not identify a clear disorder, but psychodiagnostic interviews were consistent with a DSM-5 conversion disorder. The fMRI study demonstrated that speech network activations corresponded to those found in healthy participants. Conclusion: The clinical neurolinguistic characteristics, outcome of the fMRI experiment, together with the clinical psychodiagnostic findings were strongly indicative for an underlying functional etiology for the FAS and jargon speech, presenting as symptoms of conversion disorder.
We propose the fuzzy lexical representations (FLRs) hypothesis that regards fuzziness as a core property of nonnative (L2) lexical representations (LRs). Fuzziness refers to imprecise encoding at different levels of LRs and interacts with input frequency during lexical processing and learning in adult L2 speakers. The FLR hypothesis primarily focuses on the encoding of spoken L2 words. We discuss the causes of fuzzy encoding of phonological form and meaning as well as fuzzy form-meaning mappings and the consequences of fuzzy encoding for word storage and retrieval. A central factor contributing to the fuzziness of L2 LRs is the fact that the L2 lexicon is acquired when the L1 lexicon is already in place. There are two immediate consequences of such sequential learning. First, L2 phonological categorization difficulties lead to fuzzy phonological form encoding. Second, the acquisition of L2 word forms subsequently to their meanings, which had already been acquired together with the L1 word forms, leads to weak L2 form-meaning mappings. The FLR hypothesis accounts for a range of phenomena observed in L2 lexical processing, including lexical confusions, slow lexical access, retrieval of incorrect lexical entries, weak lexical competition, reliance on sublexical rather than lexical heuristics in word recognition, the precedence of word form over meaning, and the prominence of detailed, even if imprecisely encoded, information about LRs in episodic memory. The main claim of the FLR hypothesis—that the quality of lexical encoding is a product of a complex interplay between fuzziness and input frequency—can contribute to increasing the efficiency of the existing models of LRs and lexical access.
The extent to which action and perception systems of the brain are involved in semantic comprehension remains controversial. Whether figurative language, such as metaphors and idioms, is grounded in sensory-motor systems is especially contentious. Here, we used high-definition transcranial direct current stimulation (HD-tDCS) in healthy adults to examine the role of the left-hemisphere motor cortex during the comprehension of action sentences, relative to comprehension of sentences with visual verbs. Action sentences were divided into three types: literal, metaphoric, or idiomatic. This allowed us to ask whether processing of action verbs used in figurative contexts relies on motor cortex. The results revealed that action sentence comprehension response times were facilitated relative to the visual sentence control. Significant interaction relative to visual sentences was observed for literal, metaphoric, and idiomatic action sentences with HD-tDCS of the motor cortex. These results suggest that the left motor cortex is functionally involved in action sentence comprehension. Furthermore, this involvement exists when the action content of the sentences is figurative, for both idiomatic and metaphoric cases. The results provide evidence for functional links between conceptual and action systems of the brain.
Navigated Transcranial Magnetic Stimulation (nTMS) is used to understand the cortical organization of language in preparation for the surgical removal of a brain tumor. Action naming with finite verbs can be employed for that purpose, providing additional information to object naming. However, little research has focused on the properties of the verbs that are used in action naming tasks, such as their status as transitive (taking an object; e.g., to read) or intransitive (not taking an object; e.g., to wink). Previous neuroimaging data show higher activation for transitive compared to intransitive verbs in posterior perisylvian regions bilaterally. In the present study, we employed nTMS and production of finite verbs to investigate the cortical underpinnings of transitivity. Twenty neurologically healthy native speakers of German participated in the study. They underwent language mapping in both hemispheres with nTMS. The action naming task with finite verbs consisted of transitive (e.g., The man reads the book) and intransitive verbs (e.g., The woman winks) and was controlled for relevant psycholinguistic variables. Errors were classified in four different error categories (i.e., non-linguistic errors, grammatical errors, lexico-semantic errors and, errors at the sound level) and were analyzed quantitatively. We found more nTMS-positive points in the left hemisphere, particularly in the left parietal lobe for the production of transitive compared to intransitive verbs. These positive points most commonly corresponded to lexico-semantic errors. Our findings are in line with previous aphasia and neuroimaging studies, suggesting that a more widespread network is used for the production of verbs with a larger number of arguments (i.e., transitives). The higher number of lexico-semantic errors with transitive compared to intransitive verbs in the left parietal lobe supports previous claims for the role of left posterior areas in the retrieval of argument structure information.