Comparison of Functional Network Connectivity for Passive-Listening and Active-Response Narrative Comprehension in Adolescents

Comprehension of narrative stories plays an important role in the development of language skills. In this study, we compared brain activity elicited by a passive-listening version and an active-response (AR) version of a narrative comprehension task by using independent component (IC) analysis on functional magnetic resonance imaging data from 21 adolescents (ages 14–18 years). Furthermore, we explored differences in functional network connectivity engaged by two versions of the task and investigated the relationship between the online response time and the strength of connectivity between each pair of ICs. Despite similar brain region involvements in auditory, temporoparietal, and frontoparietal language networks for both versions, the AR version engages some additional network elements including the left dorsolateral prefrontal, anterior cingulate, and sensorimotor networks. These additional involvements are likely associated with working memory and maintenance of attention, which can be attributed to the differences in cognitive strategic aspects of the two versions. We found significant positive correlation between the online response time and the strength of connectivity between an IC in left inferior frontal region and an IC in sensorimotor region. An explanation for this finding is that longer reaction time indicates stronger connection between the frontal and sensorimotor networks caused by increased activation in adolescents who require more effort to complete the task

Linking sentence production and comprehension: The neural mechanisms underlying production and comprehension control processes

This thesis investigated the relationship between sentence production and comprehension. A combination of behavioural and neuroimaging techniques were used to examine the extent to which sentence production and comprehension engage common or distinct mechanisms, with specific focus on the processes engaged by semantic/syntactic competition. Behavioural studies in Chapter 2 indicated that high-competition cases were more difficult to understand and produce than low-competition cases, and that difficulty varied as a function of the number of alternative associations entertained during performance in both tasks. In Chapter 3, an fMRI study indicated that production and comprehension shared a common competition mechanism within left inferior frontal gyrus (LIFG). However, they engage distinctive networks that interact with LIFG, with production eliciting a larger network including areas involved in sentence planning and memory retrieval. Further asymmetries across tasks were revealed in Chapter 4, in which behavioural results and neural networks were compared across adults and adolescents. This study also demonstrated the occurrence of shifts in the neural networks involved in competition resolution throughout development, thereby providing a strong link between poor behavioural performance and the underdevelopment of pre-frontal inhibitory mechanisms in adolescents. Chapter 5 used an improved experimental paradigm from that in Chapters 3 and 4. The results showed that production elicits more activity than comprehension in the dorsal language route thus confirming the engagement of task-specific control processes. Interestingly, this study also revealed a common area of LIFG involved in both tasks, but also differences within LIFG, suggesting the possibility of task-specific circuitry. Together, the findings suggest that production and comprehension share fronto-temporal areas that store and manage abstract linguistic associations between words and structures. However, they differ in the manner in which linguistic information is used, as is evident by the recruitment of distinct networks. Implications for models of language processing are discussed

Music Therapy and Autism Spectrum Disorder: Literature Review

Autism spectrum disorder is a complex neurobiological disorder that affects social interaction, communication, and behavior. While there is no cure, MT has emerged as one of the most effective ways to improve the quality of life for individuals with autism. Music can help with communication, emotional expression, and reducing anxiety, providing a structured and predictable environment. MT can be used as a tool for self-expression, learning new concepts, and improving motor control. However, more research is needed to develop disease-modifying therapies that target the core deficits of the disorder.A perturbação do espectro do autismo é uma condição neurobiológica complexa que afeta a comunicação, a interação social e o comportamento. As causas exatas desta condição não são totalmente compreendidas, mas está estabelecido que se baseiam numa combinação de fatores genéticos e ambientais. Nos últimos anos, a prevalência da perturbação do espetro do autismo aumentou, gerando mais atenção e pesquisas. Atualmente não há cura para o autismo, mas existem muitas maneiras de controlar e tratar os sintomas associados, por exemplo através da musicoterapia. Este tipo de abordagem surgiu como uma intervenção promissora que pode ajudar indivíduos com autismo a melhorar sua qualidade de vida, especialmente a desenvolver capacidades sociais a nível de comunicação e interação com outras pessoas, dentro ou fora do círculo familiar. Os musicoterapeutas usam uma variedade de instrumentos e ferramentas para ajudar estes indivíduos a expressar as suas emoções e comunicar os seus sentimentos. Além disso, a música fornece um ambiente organizado e previsível que pode ajudar a melhorar o foco e, consequentemente, reduzir a ansiedade. A musicoterapia também pode ser usada como meio de ensino ativo ou passivo, visando explorar e desenvolver a autoconsciência e a autoexpressão. Do ponto de vista neurofisiológico, a música pode também ser um caminho para desenvolver a plasticidade cortical em indivíduos autistas, ou seja, pode ajudar a reconectar os circuitos sensoriomotores cerebelares e cerebrais, melhorando o controle motor e reduzindo comportamentos repetitivos. Isto deve-se ao facto da música ter a capacidade de fortalecer as conexões sinápticas entre diferentes áreas corticais somatossensoriais do cérebro, destacando a importância do sistema de neurônios-espelho e da ínsula anterior. Embora os mecanismos do funcionamento da musicoterapia ainda não sejam totalmente compreendidos, a pesquisa sugere que pode influenciar positivamente a comunicação, a interação social e a expressão emocional em indivíduos com autismo, e isso deve motivar a novas investigações, mais precisas e direcionadas ao indivíduo em questão

A Linear Structural Equation Model for Covert Verb Generation Based on Independent Component Analysis of fMRI Data from Children and Adolescents

Human language is a complex and protean cognitive ability. Young children, following well defined developmental patterns learn language rapidly and effortlessly producing full sentences by the age of 3 years. However, the language circuitry continues to undergo significant neuroplastic changes extending well into teenage years. Evidence suggests that the developing brain adheres to two rudimentary principles of functional organization: functional integration and functional specialization. At a neurobiological level, this distinction can be identified with progressive specialization or focalization reflecting consolidation and synaptic reinforcement of a network (Lenneberg, 1967; Muller et al., 1998; Berl et al., 2006). In this paper, we used group independent component analysis and linear structural equation modeling (McIntosh and Gonzalez-Lima, 1994; Karunanayaka et al., 2007) to tease out the developmental trajectories of the language circuitry based on fMRI data from 336 children ages 5–18 years performing a blocked, covert verb generation task. The results are analyzed and presented in the framework of theoretical models for neurocognitive brain development. This study highlights the advantages of combining both modular and connectionist approaches to cognitive functions; from a methodological perspective, it demonstrates the feasibility of combining data-driven and hypothesis driven techniques to investigate the developmental shifts in the semantic network

Involvement of the right hemisphere in reading comprehension: a DTI study

The Simple View of reading emphasizes the critical role of two factors in normal reading skills: word recognition and reading comprehension. The current study aims to identify the anatomical support for aspects of reading performance that fall within these two components. Fractional anisotropy (FA) values were obtained from Diffusion Tensor images in twenty-one typical adolescents and young adults using the Tract Based Spatial Statistics (TBSS) method. We focused on the Arcuate Fasciculus (AF) and Inferior Longitudinal Fasciculus (ILF) as fiber tracts that connect regions already implicated in the distributed cortical network for reading. Our results demonstrate dissociation between word-level and narrative-level reading skills: the FA values for both left and right ILF were correlated with measures of word reading, while only the left ILF correlated with reading comprehension scores. FA in the AF, however, correlated only with reading comprehension scores, bilaterally. Correlations with the right AF were particularly robust, emphasizing the contribution of the right hemisphere, especially the frontal lobe, to reading comprehension performance on the particular passage comprehension test used in this study. The anatomical dissociation between these reading skills is supported by the Simple View theory and may shed light on why these two skills dissociate in those with reading disorders

Prefrontal Cortex: Role in Language Communication during Social Interaction

One important question that remains open for the relationship between the brain and social behavior is whether and how prefrontal mechanisms responsible for social cognitive processes take place in language communication. Conventional studies have highlighted the role of inferior frontal gyrus (IFG) in processing context-independent linguistic information in speech and discourse. However, it is unclear how the medial prefrontal cortex (mPFC), the lateral prefrontal cortex (lPFC), and other structures (such as medial superior frontal gyrus, premotor cortex, anterior cingulate cortex, etc.) are involved when socially relevant language is encountered in real-life scenarios. Emerging neuroimaging and patient studies have suggested the association of prefrontal regions with individual differences and impairments in the comprehension of speech act, nonliteral language, or construction-based pragmatic information. By summarizing and synthesizing the most recent functional magnetic resonance imaging (fMRI) studies, this chapter aims to show how neurocognitive components underlying the social function of prefrontal cortex support pragmatic language processing, such as weighing relevant social signals, resolving ambiguities, and identifying hidden speaker meanings. The conclusion lends impact on an emerging interest in neuropragmatics and points out a promising line of research to address the mediating role of prefrontal cortex in the relation of language and social cognition

Neuroimaging investigations of language to aid paediatric neurosurgical decision making

Childhood onset epilepsy can have a profound effect on cognitive, emotional and behavioural development. As such, early intervention is crucial. Approximately 25-50% of children with epilepsy show resistance to medication however. For these children, neurosurgical intervention may be considered. The decision for surgery is a multi-disciplinary process, including functional Magnetic Resonance Imaging (fMRI) to assess the risk posed by surgery to language. Based on feasibility and behavioural pilot studies, I developed an fMRI task panel optimised for pre-surgical investigations of language in children. This task panel maps different language systems (word retrieval, sentence generation, auditory comprehension and reading comprehension) and localises critical language functions (semantic and syntactic processing). I validated this task panel in healthy children (N=43, 5-16 years). This included assessments of scan quality, comparison of methods for artefact repair, and definition of typical activation patterns. I also piloted the new task panel in a representative sample of children with epilepsy, who were being considered for surgery (N=13, aged 5-16 years). Patient case studies are reported to highlight methodological challenges associated with localisation of critical language regions on an individual basis. Finally, I present experimental analyses which highlight the importance of the ventral system to semantic processing. Activation in this network was reduced in children with epilepsy and predicted language outcome. Further investigation showed prolonged development of specific nodes within this system, supporting multimodal semantic processing (independent of effort and performance accuracy). These regions included ventral occipito-temporal cortex, whose role in semantic processing has so far been underappreciated in the developmental literature. These analyses provide evidence for a core language system, which may be crucial for post-surgical language outcome. The findings from this thesis contribute towards extending and improving the role of fMRI in the surgical decision-making process, with the potential for improving long term outcome. They also contribute to models of typical and atypical language development

Building an adaptive brain across development: targets for neurorehabilitation must begin in infancy

Much progress has been made toward behavioural and pharmacological intervention in intellectual disability, which was once thought too difficult to treat. Down syndrome research has shown rapid advances, and clinical trials are currently underway, with more on the horizon. Here, we review the literature on the emergent profile of cognitive development in Down syndrome, emphasizing that treatment approaches must consider how some “end state” impairments, such as language deficits, may develop from early alterations in neural systems beginning in infancy. Specifically, we highlight evidence suggesting that there are pre- and early postnatal alterations in brain structure and function in Down syndrome, resulting in disturbed network function across development. We stress that these early alterations are likely amplified by Alzheimer’s disease progression and poor sleep. Focusing on three network hubs (prefrontal cortex, hippocampus, and cerebellum), we discuss how these regions may relate to evolving deficits in cognitive function in individuals with Down syndrome, and to their language profile in particular