White matter in infancy is prospectively associated with language outcomes in kindergarten

Whole-brain white matter variation across childhood environments

White matter develops over the course of childhood in an experience-dependent manner. However, its role in the relationship between the early environment and later cognition is unclear, in part due to focus on changes in specific gray matter regions. This study examines white matter differences across adolescents from diverse environments, evaluating both their extent throughout the brain and their contribution to cognitive outcomes. Using data from the Adolescent Brain Cognitive Development (ABCD) study (N = 9,082, female = 4,327), we found extensive cross-sectional associations with lower white matter fractional anisotropy (FA) and streamline count in the brains of 9- and 10-y-old children exposed to a range of experiences, including prenatal risk factors, interpersonal adversity, household economic deprivation, and neighborhood adversity. Lower values of FA were associated with later difficulties with mental arithmetic and receptive language. Furthermore, white matter FA partially mediated the detrimental relationship between adversity and cognition later in adolescence. These findings advance a white matter-based account of the neural and cognitive effects of adversity, which supports leading developmental theories that place interregional connectivity prior to gray matter maturation.

Longitudinal trajectories of brain development from infancy to school age and their relationship to literacy development

Reading is one of the most complex skills that we utilize daily, and it involves the early development and interaction of various lower-level subskills, including phonological processing and oral language. These subskills recruit brain structures, which begin to develop long before the skill manifests and exhibit rapid development during infancy. However, how longitudinal trajectories of early brain development in these structures supports long-term acquisition of literacy subskills and subsequent reading is unclear. Children underwent structural and diffusion MRI scanning at multiple timepoints between infancy and second grade and were tested for literacy subskills in preschool and decoding and word reading in early elementary school. We developed and implemented a reproducible pipeline to generate longitudinal trajectories of early brain development to examine associations between these trajectories and literacy (sub)skills. Furthermore, we examined whether familial risk of reading difficulty and home literacy environment, two common literacy-related covariates, influenced those trajectories. Results showed that individual differences in curve features (e.g., intercepts and slopes) for longitudinal trajectories of volumetric, surface-based, and white matter organization measures were linked directly to phonological processing and indirectly to second-grade decoding and word reading skills via phonological processing. Altogether, these findings suggest that the brain bases of phonological processing, previously identified as the strongest behavioral predictor of reading and decoding skills, may already begin to develop early in infancy but undergo further refinement between birth and preschool. The present study underscores the importance of considering academic skill acquisition from the very beginning of life.

Phonological decoding ability is associated with fiber density of the left arcuate fasciculus longitudinally across reading development

Numerous studies have linked reading ability to white matter microstructure using diffusion tensor imaging, but findings have been inconsistent and lack specificity. Fiber-specific diffusion-weighted magnetic resonance imaging (dMRI) models offer enhanced precision in measuring specific microstructural features, but they have not yet been applied to examine associations between reading ability and white matter microstructure development as children learn to read. We applied constrained spherical deconvolution (CSD) and fiber-specific modelling to characterize developmental changes in fiber density of key white matter tracts of the reading network, and investigated associations between tract-wise fiber density and children's phonological decoding abilities. Fiber density was measured from ages 2-13 years, and decoding ability (pseudoword reading) was assessed at ages 6 years and older. Higher decoding ability was associated with greater fiber density in the left arcuate fasciculus, and effects remained consistent over time. Follow-up analysis revealed that asymmetry changes in the arcuate fasciculus were moderated by decoding ability: good decoders showed leftward asymmetry from early childhood onward, while poorer decoders shifted toward leftward asymmetry over time. These results suggest that densely organized fibers in the left arcuate fasciculus serve as a foundation for the development of reading skills from the pre-reading stage through fluent reading.

The role of formal schooling in the development of children's reading and arithmetic white matter networks

Children's white matter development is driven by experience, yet it remains poorly understood how it is shaped by attending formal education. A small number of studies compared children before and after the start of formal schooling to understand this, yet they do not allow to separate maturational effects from schooling-related effects. A clever way to (quasi-)experimentally address this issue is the longitudinal school cut-off design, which compares children who are similar in age but differ in schooling (because they are born right before or after the cut-off date for school entry). We used for the first time such a longitudinal school cut-off design to experimentally investigate the effect of schooling on children's white matter networks. We compared "young" first graders (schooling group, n = 34; Mage = 68 months; 20 girls) and "old" preschoolers (non-schooling group, n = 33; Mage = 66 months; 18 girls) that were similar in age but differed in the amount of formal instruction they received. Our study revealed that changes in fractional anisotropy and mean diffusivity in five a priori selected white matter tracts during the transition from preschool to primary school were predominantly driven by age-related maturation. We did not find specific schooling effects on white matter, despite their strong presence for early reading and early arithmetic skills. The present study is the first to disentangle the effects of age-related maturation and schooling on white matter within a longitudinal cohort of 5-year-old preschoolers. RESEARCH HIGHLIGHTS: White matter tracts that have been associated with reading and arithmetic may be susceptible to experience-dependent neuroplasticity when children learn to read and calculate. This longitudinal study used the school cut-off design to isolate schooling-induced from coinciding maturational influences on children's white matter development. White matter changes during the transition from preschool to primary school are predominantly driven by age-related maturation and not by schooling effects. Strong effects of schooling on behavior were shown for early reading and early arithmetic, but not for verbal ability and spatial ability.

Early language processing efficiency and pre-literacy outcomes in children born full term and preterm

Language processing efficiency-that is, the skill at processing language in real time-assessed in toddlerhood is associated with later language outcomes in children born full term (FT) and preterm (PT) during school age. No studies to date have assessed patterns of relations between early language processing efficiency and pre-literacy skills, such as print knowledge and phonological awareness, and whether relations are similar in FT and PT children. In this study, participants (N = 94, 49 FT and 45PT) were assessed in the looking-while-listening (LWL) task at 18 months of age (corrected for degree of prematurity), deriving measures of processing speed and accuracy. At 4½ years of age, children were assessed on standardized tests of print knowledge, phonological awareness, and expressive language. Processing speed and accuracy predicted both pre-literacy outcomes (r2 change = 7.8%-19.5%, p < .01); birth group did not moderate these effects. Relations were significantly reduced when controlling for expressive language. Thus, early language processing efficiency supports later expressive language abilities, which in turn supports developing pre-literacy skills. Processing speed and phonological awareness were also directly related, indicating an independent role for processing speed in literacy development. Mediation effects were not moderated by birth group, suggesting a similar developmental pathway in FT and PT children.

Lateralization of activation within the superior temporal gyrus during speech perception in sleeping infants is associated with subsequent language skills in kindergarten: A passive listening task-fMRI study

Brain asymmetries are hypothesized to reduce functional duplication and thus have evolutionary advantages. The goal of this study was to examine whether early brain lateralization contributes to skill development within the speech-language domain. To achieve this goal, 25 infants (2-13 months old) underwent behavioral language examination and fMRI during sleep while listening to forward and backward speech, and then were assessed on various language skills at 55-69 months old. We observed that infant functional lateralization of the superior temporal gyrus (STG) for forward > backward speech was associated with phonological, vocabulary, and expressive language skills 4 to 5 years later. However, we failed to observe that infant language skills or the anatomical lateralization of STG were related to subsequent language skills. Overall, our findings suggest that infant functional lateralization of STG for speech perception may scaffold subsequent language acquisition, supporting the hypothesis that functional hemisphere asymmetries are advantageous.

Prenatal tobacco and alcohol exposure, white matter microstructure, and early language skills in toddlers from a South African birth cohort

Introduction

Tobacco and alcohol are the two most common substances used during pregnancy, and both can disrupt neurodevelopment, resulting in cognitive and behavioral deficits including language difficulties. Previous studies show that children with prenatal substance exposure exhibit microstructural alterations in major white matter pathways, though few studies have investigated the impact of prenatal substance exposure on white matter microstructure and language skills during the toddler years.

Methods

In this study, 93 children (34 exposed to alcohol and/or tobacco) aged 23 years from the Drakenstein Child Health Study, South Africa, completed Expressive and Receptive Communication assessments from the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) and underwent diffusion MRI scans. Diffusion images were preprocessed, and 11 major white matter tracts were isolated. Fractional anisotropy (FA) and mean diffusivity (MD) were extracted for each white matter tract. Linear regression was used to examine differences between the tobacco/alcohol exposed group and unexposed controls for FA, MD, and language scores, as well as relationships between brain metrics and language. There were no significant group differences in language scores or FA.

Results

Children with alcohol or tobacco exposure had lower average MD in the splenium of the corpus callosum compared to unexposed controls. Significant interactions between prenatal substance exposure and language scores were seen in 7 tracts but did not survive multiple comparisons correction.

Discussion

Our findings show that prenatal alcohol and/or tobacco exposure appear to alter the relationship between white matter microstructure and early language skills in this population of toddlers, potentially laying the basis of language deficits observed later in older children with prenatal substance exposure, which may have implications for learning and interventions.

Longitudinal associations between language network characteristics in the infant brain and school-age reading abilities are mediated by early-developing phonological skills

Reading acquisition is a prolonged learning process relying on language development starting in utero. Behavioral longitudinal studies reveal prospective associations between infant language abilities and preschool/kindergarten phonological development that relates to subsequent reading performance. While recent pediatric neuroimaging work has begun to characterize the neural network underlying language development in infants, how this neural network scaffolds long-term language and reading acquisition remains unknown. We addressed this question in a 7-year longitudinal study from infancy to school-age. Seventy-six infants completed resting-state fMRI scanning, and underwent standardized language assessments in kindergarten. Of this larger cohort, forty-one were further assessed on their emergent word reading abilities after receiving formal reading instructions. Hierarchical clustering analyses identified a modular infant language network in which functional connectivity (FC) of the inferior frontal module prospectively correlated with kindergarten-age phonological skills and emergent word reading abilities. These correlations were obtained when controlling for infant age at scan, nonverbal IQ and parental education. Furthermore, kindergarten-age phonological skills mediated the relationship between infant FC and school-age reading abilities, implying a critical mid-way milestone for long-term reading development from infancy. Overall, our findings illuminate the neurobiological mechanisms by which infant language capacities could scaffold long-term reading acquisition.

Longitudinal associations between language network characteristics in the infant brain and school-age reading abilities are mediated by early-developing phonological skills

Reading acquisition is a prolonged learning process relying on language development starting in utero. Behavioral longitudinal studies reveal prospective associations between infant language abilities and preschool/kindergarten phonological development that relates to subsequent reading performance. While recent pediatric neuroimaging work has begun to characterize the neural network underlying language development in infants, how this neural network scaffolds long-term language and reading acquisition remains unknown. We addressed this question in a 7-year longitudinal study from infancy to school-age. Seventy-six infants completed resting-state fMRI scanning, and underwent standardized language assessments in kindergarten. Of this larger cohort, forty-one were further assessed on their emergent word reading abilities after receiving formal reading instructions. Hierarchical clustering analyses identified a modular infant language network in which functional connectivity (FC) of the inferior frontal module prospectively correlated with kindergarten-age phonological skills and emergent word reading abilities. These correlations were obtained when controlling for infant age at scan, nonverbal IQ and parental education. Furthermore, kindergarten-age phonological skills mediated the relationship between infant FC and school-age reading abilities, implying a critical mid-way milestone for long-term reading development from infancy. Overall, our findings illuminate the neurobiological mechanisms by which infant language capacities could scaffold long-term reading acquisition.

Leveraging brain science for impactful advocacy and policymaking: The synergistic partnership between developmental cognitive neuroscientists and a parent-led grassroots movement to drive dyslexia prevention policy and legislation

Reading proficiency is crucial for academic, vocational, and economic success and has been closely linked to health outcomes. Unfortunately, in the United States, a concerning 63% of fourth-grade children are reading below grade level, with approximately 7%-10% exhibiting a disability in word reading, developmental dyslexia. Research in developmental cognitive neuroscience indicates that individuals with dyslexia show functional and structural brain alterations in regions processing reading and reading-related information, with some of these differences emerging as early as preschool and even infancy. This suggests that some children start schooling with less optimal brain architecture for learning to read, emphasizing the need for preventative education practices. This article reviews educational policies impacting children with dyslexia and highlights a decentralized parent-led grassroots movement, Decoding Dyslexia, which centers the voices of those directly impacted by dyslexia. It utilizes civic engagement practices, advocacy and lobbying on local, federal, and social media platforms, and strong partnerships with scientists to drive systems-level change in educational practices, leading to dyslexia prevention legislation across the U.S. The ongoing partnership continues to address the profound gaps between scientific findings and policymaking to drive systems-level change for contemporary challenges in educational practices within a learning disabilities framework.

White matter microstructural plasticity associated with educational intervention in reading disability

Children's reading progress typically slows during extended breaks in formal education, such as summer vacations. This stagnation can be especially concerning for children with reading difficulties or disabilities, such as dyslexia, because of the potential to exacerbate the skills gap between them and their peers. Reading interventions can prevent skill loss and even lead to appreciable gains in reading ability during the summer. Longitudinal studies relating intervention response to brain changes can reveal educationally relevant insights into rapid learning-driven brain plasticity. The current work focused on reading outcomes and white matter connections, which enable communication among the brain regions required for proficient reading. We collected reading scores and diffusion-weighted images at the beginning and end of summer for 41 children with reading difficulties who had completed either 1st or 2nd grade. Children were randomly assigned to either receive an intensive reading intervention (n = 26; Seeing Stars from Lindamood-Bell which emphasizes orthographic fluency) or be deferred to a wait-list group (n = 15), enabling us to analyze how white matter properties varied across a wide spectrum of skill development and regression trajectories. On average, the intervention group had larger gains in reading compared to the non-intervention group, who declined in reading scores. Improvements on a proximal measure of orthographic processing (but not other more distal reading measures) were associated with decreases in mean diffusivity within core reading brain circuitry (left arcuate fasciculus and left inferior longitudinal fasciculus) and increases in fractional anisotropy in the left corticospinal tract. Our findings suggest that responses to intensive reading instruction are related predominantly to white matter plasticity in tracts most associated with reading.

Neurobiological predispositions for musicality: White matter in infancy predicts school-age music aptitude

Musical training has long been viewed as a model for experience-dependent brain plasticity. Reports of musical training-induced brain plasticity are largely based on cross-sectional studies comparing musicians to non-musicians, which cannot address whether musical training itself is sufficient to induce these neurobiological changes or whether pre-existing neuroarchitecture before training predisposes children to succeed in music. Here, in a longitudinal investigation of children from infancy to school age (n = 25), we find brain structure in infancy that predicts subsequent music aptitude skills at school-age. Building on prior evidence implicating white matter organization of the corticospinal tract as a neural predisposition for musical training in adults, here we find that structural organization of the right corticospinal tract in infancy is associated with school-age tonal and rhythmic musical aptitude skills. Moreover, within the corpus callosum, an inter-hemispheric white matter pathway traditionally linked with musical training, we find that structural organization of this pathway in infancy is associated with subsequent tonal music aptitude. Our findings suggest predispositions prior to the onset of musical training from as early as infancy may serve as a scaffold upon which ongoing musical experience can build. RESEARCH HIGHLIGHTS: Structural organization of the right corticospinal tract in infancy is associated with school-age musical aptitude skills. Longitudinal associations between the right corticospinal tract in infancy and school-age rhythmic music aptitude skills remain significant even when controlling for language ability. Findings support the notion of predispositions for success in music, and suggest that musical predispositions likely build upon a neural structural scaffold established in infancy. Findings support the working hypothesis that a dynamic interaction between predisposition and experience established in infancy shape the trajectory of long-term musical development.

Associations between early efficiency in language processing and language and cognitive outcomes in children born full term and preterm: similarities and differences

Associations between children's early language processing efficiency and later verbal and non-verbal outcomes shed light on the extent to which early information processing skills support later learning across different domains of function. Examining whether the strengths of associations are similar in typically developing and at-risk populations provides an additional lens into the varying routes to learning that children may take across development. In this follow-up study, children born full-term (FT, n = 49) and preterm (PT, n = 45, ≤32 weeks gestational age, birth weight <1800 g) were assessed in the Looking While Listening (LWL) task at 18 months (corrected for degree of prematurity in PT group). This eye-tracking task assesses efficiency of real-time spoken language comprehension as accuracy and speed (RT) of processing. At 4 ½ years, children were assessed on standardized tests of receptive vocabulary, expressive language, and non-verbal IQ. Language processing efficiency was associated with both language outcomes (r2-change: 7.0-19.7%, p < 0.01), after covariates. Birth group did not moderate these effects, suggesting similar mechanisms of learning in these domains for PT and FT children. However, birth group moderated the association between speed and non-verbal IQ (r2-change: 4.5%, p < 0.05), such that an association was found in the PT but not the FT group. This finding suggests that information processing skills reflected in efficiency of real-time language processing may be recruited to support learning in a broader range of verbal and non-verbal domains in the PT compared to the FT group.

White matter correlates of reading subskills in children with and without reading disability

Individual differences in reading ability are associated with characteristics of white matter microstructure in the brain. However, previous studies have largely measured reading as a single construct, resulting in difficulty characterizing the role of structural connectivity in discrete subskills of reading. The present study used diffusion tensor imaging to examine how white matter microstructure, measured by fractional anisotropy (FA), relates to individual differences in reading subskills in children aged 8 to 14 (n = 65). Findings showed positive correlations between FA of the left arcuate fasciculus and measures of single word reading and rapid naming abilities. Negative correlations were observed between FA of the right inferior longitudinal fasciculus and bilateral uncinate fasciculi, and reading subskills, particularly reading comprehension. The results suggest that although reading subskills rely to some extent on shared tracts, there are also distinct characteristics of white matter microstructure supporting different components of reading ability in children.

Examining Shared Reading and White Matter Organization in Kindergarten in Relation to Subsequent Language and Reading Abilities: A Longitudinal Investigation

Parent-child language interaction in early childhood carries long-term implications for children's language and reading development. Conversational interaction, in particular, has been linked to white matter organization of neural pathways critical for language and reading. However, shared book reading serves an important role for language interaction as it exposes children to sophisticated vocabulary and syntax. Despite this, it remains unclear whether shared reading also relates to white matter characteristics subserving language and reading development. If so, to what extent do these environmentally associated changes in white matter organization relate to subsequent reading outcomes? This longitudinal study examined shared reading and white matter organization in kindergarten in relation to subsequent language and reading outcomes among 77 typically developing children. Findings reveal positive associations between the number of hours children are read to weekly (shared reading time) and the fractional anisotropy of the left arcuate fasciculus, as well as left lateralization of the superior longitudinal fasciculus (SLF). Furthermore, left lateralization of the SLF in these kindergarteners is associated with subsequent reading abilities in second grade. Mediation analyses reveal that left lateralization of the SLF fully mediates the relationship between shared reading time and second-grade reading abilities. Results are significant when controlling for age and socioeconomic status. This is the first evidence demonstrating how white matter structure, in relation to shared reading in kindergarten, is associated with school-age reading outcomes. Results illuminate shared reading as a key proxy for the home language and literacy environment and further our understanding of how language interaction may support neurocognitive development.

Home language and literacy environment and its relationship to socioeconomic status and white matter structure in infancy

The home language and literacy environment (HLLE) in infancy has been associated with subsequent pre-literacy skill development and HLLE at preschool-age has been shown to correlate with white matter organization in tracts that subserve pre-reading and reading skills. Furthermore, childhood socioeconomic status (SES) has been linked with both HLLE and white matter organization. It is important to understand whether the relationships between environmental factors such as HLLE and SES and white matter organization can be detected as early as infancy, as this period is characterized by rapid brain development that may make white matter pathways particularly susceptible to these early experiences. Here, we hypothesized that HLLE (1) relates to white matter organization in pre-reading and reading-related tracts in infants, and (2) mediates a link between SES and white matter organization. To test these hypotheses, infants (mean age: 8.6 ± 2.3 months, N = 38) underwent diffusion-weighted imaging MRI during natural sleep. Image processing was performed with an infant-specific pipeline and fractional anisotropy (FA) was estimated from the arcuate fasciculus (AF) and superior longitudinal fasciculus (SLF) bilaterally using the baby automated fiber quantification method. HLLE was measured with the Reading subscale of the StimQ (StimQ-Reading) and SES was measured with years of maternal education. Self-reported maternal reading ability was also quantified and applied to our statistical models as a proxy for confounding genetic effects. StimQ-Reading positively correlated with FA in left AF and to maternal education, but did not mediate the relationship between them. Taken together, these findings underscore the importance of considering HLLE from the start of life and may inform novel prevention and intervention strategies to support developing infants during a period of heightened brain plasticity.

Multimodal brain features at 3 years of age and their relationship with pre-reading measures 1 year later

Pre-reading language skills develop rapidly in early childhood and are related to brain structure and functional architecture in young children prior to formal education. However, the early neurobiological development that supports these skills is not well understood. Here we acquired anatomical, diffusion tensor imaging (DTI) and resting state functional MRI (rs-fMRI) from 35 children at 3.5 years of age. Children were assessed for pre-reading abilities using the NEPSY-II subtests 1 year later (4.5 years). We applied a data-driven linked independent component analysis (ICA) to explore the shared co-variation of gray and white matter measures. Two sources of structural variation at 3.5 years of age demonstrated relationships with Speeded Naming scores at 4.5 years of age. The first imaging component involved volumetric variability in reading-related cortical regions alongside microstructural features of the superior longitudinal fasciculus (SLF). The second component was dominated by cortical volumetric variations within the cerebellum and visual association area. In a subset of children with rs-fMRI data, we evaluated the inter-network functional connectivity of the left-lateralized fronto-parietal language network (FPL) and its relationship with pre-reading measures. Higher functional connectivity between the FPL and the default mode and visual networks at 3.5 years significantly predicted better Phonological Processing scores at 4.5 years. Together, these results suggest that the integration of functional networks, as well as the co-development of white and gray matter brain structures in early childhood, support the emergence of pre-reading measures in preschool children.

Associations between Brain Microstructure and Phonological Processing Ability in Preschool Children

Neuroimaging studies have associated brain changes in children with future reading and language skills, but few studies have investigated the association between language skills and white matter structure in preschool-aged children. Using 208 data sets acquired in 73 healthy children aged 2–7 years, we investigated the relationship between developmental brain microstructure and phonological processing ability as measured using their phonological processing raw score (PPRS). The correlation analysis showed that across the whole age group, with increasing age, PPRS increased, fractional anisotropy (FA) of the internal capsule and inferior fronto-occipital fasciculus and some other regions increased, and mean diffusivity (MD) of the corpus callosum and internal capsule and some other regions decreased. The results of the mediation analysis suggest that increased FA may be the basis of phonological processing ability development during this period, and the increased number of fiber connections between the right inferior parietal lobule and right supramarginal gyrus may be a key imaging feature of phonological processing ability development. Our study reflects the changes in brain microstructure and contributes to understanding the underlying neural mechanisms of language development in preschool children.

Myelin water fraction in relation to fractional anisotropy and reading in 10-year-old children

Diffusion-weighted imaging studies have repeatedly shown that white matter correlates with reading throughout development. However, the neurobiological interpretation of this relationship is constrained by the limited microstructural specificity of diffusion imaging. A critical component of white matter microstructure is myelin, which can be investigated noninvasively using MRI. Here, we examined the link between myelin water fraction (MWF) and reading ability in 10-year-old children (n = 69). To better understand this relationship, we additionally investigated how these two variables relate to fractional anisotropy (FA; a common index of diffusion-weighted imaging). Our analysis revealed that lower MWF coheres with better reading scores in left-hemispheric tracts relevant for reading. While we replicated previous reports on a positive relationship between FA and MWF, we did not find any evidence for an association between reading and FA. Together, these findings contrast previous research suggesting that poor reading abilities might be rooted in lower myelination and emphasize the need for further longitudinal research to understand how this relationship evolves throughout reading development. Altogether, this study contributes important insights into the role of myelin-related processes in the relationship between reading and white matter structure.

Functional Connectivity in Infancy and Toddlerhood Predicts Long-Term Language and Preliteracy Outcomes

Functional connectivity (FC) techniques can delineate brain organization as early as infancy, enabling the characterization of early brain characteristics associated with subsequent behavioral outcomes. Previous studies have identified specific functional networks in infant brains that underlie cognitive abilities and pathophysiology subsequently observed in toddlers and preschoolers. However, it is unknown whether and how functional networks emerging within the first 18 months of life contribute to the development of higher order, complex functions of language/literacy at school-age. This 5-year longitudinal imaging project starting in infancy, utilized resting-state functional magnetic resonance imaging and demonstrated prospective associations between FC in infants/toddlers and subsequent language and foundational literacy skills at 6.5 years old. These longitudinal associations were shown independently of key environmental influences and further present in a subsample of infant imaging data (≤12 months), suggesting early emerged functional networks specifically linked to high-order language and preliteracy skills. Moreover, emergent language skills in infancy and toddlerhood contributed to the prospective associations, implicating a role of early linguistic experiences in shaping the FC correlates of long-term oral language skills. The current results highlight the importance of functional organization established in infancy and toddlerhood as a neural scaffold underlying the learning process of complex cognitive functions.