Meta-analytic connectivity modeling of the left and right inferior frontal gyri

Background: Neurocognitive models of language processing highlight the role of the left inferior frontal gyrus (IFG) in the functional network underlying language. Furthermore, neuroscience research has shown that IFG is not a uniform region anatomically, cytoarchitectonically or functionally. However, no previous study explored the language-related functional connectivity patterns of IFG subdivisions using a meta-analytic connectivity modeling (MACM) approach. Purpose: The present MACM study aimed to identify language-related coactivation patterns of the left and right IFG subdivisions. Method: Six regions of interest (ROIs) were defined using a probabilistic brain atlas corresponding to pars opercularis, pars triangularis and pars orbitalis of IFG in both hemispheres. The ROIs were used to search the BrainMap functional database to identify neuroimaging experiments with healthy, right-handed participants reporting language-related activations in each ROI. Activation likelihood estimation analyses were then performed on the foci extracted from the identified studies to compute functional convergence for each ROI, which was also contrasted with the other ROIs within the same hemisphere. Results: A primarily left-lateralized functional network was revealed for the left and right IFG subdivisions. The left-hemispheric ROIs exhibited more robust coactivation than the right-hemispheric ROIs. Particularly, the left pars opercularis was associated with the most extensive coactivation pattern involving bilateral frontal, bilateral parietal, left temporal, left subcortical, and right cerebellar regions, while the left pars triangularis and orbitalis revealed a predominantly left-lateralized involvement of frontotemporal regions. Conclusion: The findings align with the neurocognitive models of language processing that propose a division of labor among the left IFG subdivisions and their respective functional networks. Also, the opercular part of left IFG stands out as a major hub in the language network with connections to diverse cortical, subcortical and cerebellar structures

Türkiye’de çocukluk çağı dil bozukluğuna ilişkin toplumsal farkındalık: Betimsel çalışma

Objective: Childhood language impairment (CLI), also known as developmental language disorder, adversely affects children’s expressive and/or receptive language development. Although relatively significant action has been taken to raise public awareness about other developmental disorders in Turkey, limited attention has been paid to CLI. Moreover, no previous study has been conducted about awareness of the Turkish population about CLI. Material and Methods: We carried out the Turkish version of a survey developed by Working Group 3 of COST Action IS1406 to estimate public awareness of CLI regarding its nature, causes and the problems associated with it. Data were collected in the form of face-to-face interviews. The sample included 87 participants from socio-economically diverse districts of İstanbul, Turkey, determined on the basis of the Human Development Index. Results: A significantly lower number of the participants reported having heard of CLI compared to autism, attention-deficit/hyperactivity disorder and speech disorder. Another finding was that women with children reported having heard of CLI significantly more than those without children. It was also observed that the participants had inadequate knowledge of the problems that individuals with CLI have and of its causes. Conclusion: The current findings highlight the need to take more action to raise public awareness about CLI in Turkey.Amaç: Çocukluk çağı dil bozukluğu (ÇÇDB), diğer adıyla gelişimsel dil bozukluğu, çocukların alıcı ve/veya ifade edici dil gelişimini olumsuz yönde etkilemektedir. Türkiye’de diğer gelişimsel bozukluklara ilişkin toplumsal farkındalığın artırılmasına yönelik ciddi çalışmalar yapılmış olmakla birlikte ÇÇDB’ye yönelik çalışmalar sınırlı kalmıştır. Ayrıca Türkiye’de ÇÇDB’ye ilişkin toplumsal farkındalık üzerine yapılmış bir çalışma bulunmamaktadır. Gereç ve Yöntemler: Bu çalışmada ÇÇDB’nin doğası, sebepleri ve ÇÇDB ile ilişkilendirilen sorunlara ilişkin toplumsal farkındalığı ölçmek amacıyla COST Aksiyonu IS1406 3. Çalışma Grubu tarafından geliştirilen anketin Türkçe versiyonu uygulanmıştır. Veriler yüz yüze gerçekleştirilen mülakatlar ile toplanmıştır. İstanbul’un sosyoekonomik açıdan farklı ilçelerinden 87 katılımcı örneklemi oluşturmuş olup bu ilçeler İnsani Gelişme Endeksi kullanılarak belirlenmiştir. Bulgular: Otizm, dikkat eksikliği hiperaktivite bozukluğu ve konuşma bozukluklarına kıyasla anlamlı oranda daha az katılımcı ÇÇDB terimini duyduğunu belirtmiştir. Çalışmanın bir diğer bulgusu, çocuğu olmayan kadınlara kıyasla çocuğu olan kadınlar arasında ÇÇDB teriminin daha fazla duyulmuş olmasıdır. Ayrıca çalışma örnekleminin, ÇÇDB’si olan bireylerin yaşadıkları sorunlar ve ÇÇDB’nin sebeplerine dair yetersiz bilgi sahibi olduğu gözlenmiştir. Sonuç: Çalışmanın bulguları, Türkiye’de ÇÇDB’ye ilişkin toplumsal farkındalığın artırılması için harekete geçilmesi gerektiğini göstermektedir

Is There a Processing Preference for Object Relative Clauses in Chinese? Evidence From ERPs

A consistent finding across head-initial languages, such as English, is that subject relative clauses (SRCs) are easier to comprehend than object relative clauses (ORCs). However, several studies in Mandarin Chinese, a head-final language, revealed the opposite pattern, which might be modulated by working memory (WM) as suggested by recent results from self-paced reading performance. In the present study, event-related potentials (ERPs) were recorded when participants with high and low WM spans (measured by forward digit span and operation span tests) read Chinese ORCs and SRCs. The results revealed an N400-P600 complex elicited by ORCs on the relativizer, whose magnitude was modulated by the WM span. On the other hand, a P600 effect was elicited by SRCs on the head noun, whose magnitude was not affected by the WM span. These findings paint a complex picture of relative clause processing in Chinese such that opposing factors involving structural ambiguities and integration of filler-gap dependencies influence processing dynamics in Chinese relative clauses

How aware is the public of the existence, characteristics and causes of language impairment in childhood and where have they heard about it? A European survey

Public awareness of language impairment in childhood (Developmental Language Disorder (DLD)) has been identified as an important determiner of research and clinical service delivery, yet studies directly assessing public awareness are lacking. This study surveyed awareness across 18 countries of Europe.Method: A questionnaire developed by an international team asked whether respondents had heard of language impairment affecting children, what they thought its manifestations and causes were and where they had heard of it. Respondents were also asked whether they had heard of autism, dyslexia, ADD/ADHD and speech disorder. The questionnaire was administered to members of the public in 18 European countries. A total of 1519 responses were obtained, spanning 6 age groups, 4 educational level groups and 3 income level groups.Results: Across all but one country, significantly fewer people had heard of language impairment than any of the other disorders (or 60 % compared to over 90 % for autism). Awareness tended to be lowest in Eastern Europe and greatest in North-Western Europe, and was influenced by education level, age and income level. People in countries with overall low and overall high awareness differed in their views on manifestations and causes. People had heard of language impairment and autism the same way - most frequently through the media, including Internet, and less frequently through their child’s school or a medical professional.Discussion: The study confirms that awareness of language impairment and knowledge of the breadth of its manifestations are low. It also suggests opportunities for how to increase awareness, including greater media coverage of language impairment and more efficient use of venues such as schools and healthcare. Ways in which cultural and linguistic differences may influence public awareness efforts are discussed, including the translatability of clinical labels and scientific terms. These may impact the acceptance of a common term and definition across all countries. As awareness campaigns are gaining momentum, the findings of this study can serve as a baseline against which to compare future findings.peer-reviewe

Neural correlates of morphological processing: An activation likelihood estimation meta-analysis

Background: Morphemes are the smallest building blocks of language that convey meaning or function. A controversial issue in psycho- and neurolinguistics is whether morphologically complex words consisting of multiple morphemes are processed in a combinatorial manner and, if so, which brain regions underlie this process. Relatively less is known about the neural underpinnings of morphological processing compared to other aspects of grammatical competence such as syntax. Purpose: The present study aimed to shed light on the neural correlates of morphological processing by examining functional convergence for inflectional morphology reported in previous neuroimaging studies. Method: A systematic literature search was performed on PubMed with search terms related to morphological complexity and neuroimaging. 16 studies (279 subjects) comparing regular inflection with stems or irregular inflection met the inclusion and exclusion criteria and were subjected to a series of activation likelihood estimation meta-analyses. Results: Significant functional convergence was found in several mainly left frontal regions for processing inflectional morphology. Specifically, the left inferior frontal gyrus (LIFG) was found to be consistently involved in morphological complexity. Diagnostic analyses revealed that involvement of posterior LIFG was robust against potential publication bias and over-influence of individual studies. Furthermore, LIFG involvement was maintained in meta-analyses of subsets of experiments that matched phonological complexity between conditions, although diagnostic analyses suggested that this conclusion may be premature. Conclusion: The findings provide evidence for combinatorial processing of morphologically complex words and inform psycholinguistic accounts of complex word processing. Furthermore, they highlight the role of LIFG in processing inflectional morphology, in addition to syntactic processing as has been emphasized in previous research. In particular, posterior LIFG seems to underlie grammatical functions encompassing inflectional morphology and syntax

The contribution of statistical learning to language and literacy acquisition

Acquisition and processing of written and spoken language is an impressive cognitive accomplishment considering the complexity of the tasks. While only humans seem to have evolved to the fullest extent the capacity that underpins these remarkable feats of development and civilization, the exact nature of such capacity has been subject to ongoing research. In this chapter, we focus on language competence and what makes it unique among the communication systems of different species. We then elaborate on the classical debate between nativist and environmentalist accounts of language acquisition, with reference to evidence for and against the critical period hypothesis. After introducing the regularity embedded in different languages and particularly in drastically different orthographies, we present behavioral and neurophysiological evidence for the sensitivity to systematic mapping between orthography and phonology. Because learning to read is to master such mapping, we assume that the ability to use statistical learning to appreciate the dependency among items would contribute to literacy acquisition. Empirical results from behavioral and neuroimaging experiments conducted in our and other laboratories provide support for the close link between statistical learning and literacy acquisition in native and foreign language. Such findings highlight the significance of domain-general statistical learning to domain-specific language acquisition, and point to an important direction for theories and practices of language education

Turkey

This book is about the management of children and young people with developmental language disorders (DLD). DLD is a relatively common condition affecting children and young people. The latest figures suggest that 9 per cent of children experience it at school entry. DLD occurs when the child’s language skills are judged to be significantly delayed relative to those of children of the same age. This judgement is usually made by means of a combination of formal assessment, observations of linguistic performance and professional judgement

The effects of single-session cathodal and bihemispheric tDCS on fluency in stuttering

Developmental stuttering is a fluency disorder that adversely affect many aspects of a person's life. Recent transcranial direct current stimulation (tDCS) studies have shown promise to improve fluency in people who stutter. To date, bihemispheric tDCS has not been investigated in this population. In the present study, we aimed to investigate the effects of single-session bihemispheric and unihemispheric cathodal tDCS on fluency in adults who stutter. We predicted that bihemispheric tDCS with anodal stimulation to the left IFG and cathodal stimulation to the right IFG would improve fluency better than the sham and cathodal tDCS to the right IFG. Seventeen adults who stutter completed this single-blind, crossover, sham-controlled tDCS experiment. All participants received 20 min of tDCS alongside metronome-timed speech during intervention sessions. Three tDCS interventions were administered: bihemispheric tDCS with anodal stimulation to the left IFG and cathodal stimulation to the right IFG, unihemispheric tDCS with cathodal stimulation to the right IFG, and sham stimulation. Speech fluency during reading and conversation was assessed before, immediately after, and one week after each intervention session. There was no significant fluency improvement in conversation for any tDCS interventions. Reading fluency improved following both bihemispheric and cathodal tDCS interventions. tDCS montages were not significantly different in their effects on fluency

Neural correlates of processing sentences and compound words in Chinese

FMRI 2nd-level analysis file