Neonatal White Matter Maturation Is Associated With Infant Language Development

Abstract

Background: While neonates have no sophisticated language skills, the neural basis for acquiring this function is assumed to already be present at birth. Receptive language is measurable by 6 months of age and meaningful speech production by 10-18 months of age. Fiber tracts supporting language processing include the corpus callosum (CC), which plays a key role in the hemispheric lateralization of language; the left arcuate fasciculus (AF), which is associated with syntactic processing; and the right AF, which plays a role in prosody and semantics. We examined if neonatal maturation of these fiber tracts is associated with receptive language development at 12 months of age. Methods: Diffusion-weighted imaging (DWI) was performed in 86 infants at 26.6 ± 12.2 days post-birth. Receptive language was assessed via the MacArthur-Bates Communicative Development Inventory at 12 months of age. Tract-based fractional anisotropy (FA) was determined using the NA-MIC atlas-based fiber analysis toolkit. Associations between neonatal regional FA, adjusted for gestational age at birth and age at scan, and language development at 12 months of age were tested using ANOVA models. Results: After multiple comparisons correction, higher neonatal FA was positively associated with receptive language at 12 months of age within the genu (p < 0.001), rostrum (p < 0.001), and tapetum (p < 0.001) of the CC and the left fronto-parietal AF (p = 0.008). No significant clusters were found in the right AF. Conclusion: Microstructural development of the CC and the AF in the newborn is associated with receptive language at 12 months of age, demonstrating that interindividual variation in white matter microstructure is relevant for later language development, and indicating that the neural foundation for language processing is laid well ahead of the majority of language acquisition. This suggests that some origins of impaired language development may lie in the intrauterine and potentially neonatal period of life. Understanding how interindividual differences in neonatal brain maturity

Naturalistic Language Input is Associated with Resting-State Functional Connectivity in Infancy

“…Although the top-down frontotemporal network develops later (Skeide et al, 2014), our results suggest that this network exists in infancy. Emergence of this network is likely supported by its structural connections, including the arcuate fasciculus, that are present in neonates (Sket et al, 2019).…”

“…Despite the relative immaturity of their language networks, sleeping infants exposed to speech sounds activate brain regions implicated in language processing in older children and adults, including the IFG and superior temporal gyrus (STG; Blasi et al, 2011). Neonates possess the white matter tracts, including the arcuate fasciculus, that connect regions of the mature language network (Sket et al, 2019).…”

Dear reviewers: Responses to common reviewer critiques about infant neuroimaging studies

“…Ample research suggests that the foundations of behavior in toddlerhood and beyond are present in neonate/early infant brain characteristics ( Chen et al, 2021 , Dickinson et al, 2021 , Girault et al, 2019 , Girault et al, 2019 ; Liu et al, 2021 ; Overfeld et al, 2020 ; Saha et al, 2020 ; Salzwedel et al, 2019 ; Short et al, 2019 ; Sket et al, 2019 ; Thomas et al, 2019 ; Zuk et al, 2021 ). Perhaps most importantly, infant neuroimaging data may also be able to predict neurodevelopmental disorders (such as autism spectrum disorder or dyslexia) years before reliable diagnoses can be made ( Emerson et al, 2017 , Hazlett et al, 2012 , Hazlett et al, 2017 , Langer et al, 2015 ).…”

Prediction of autism spectrum disorder diagnosis using nonlinear measures of language-related EEG at 6 and 12 months

“…We also observed differences between developmental time points topographically, with a noticeable shift leftwards from central-midline locations, including increased involvement of the temporal lobe and lateral frontal cortex at 12 months (Fig 1G). This shift may indicate that infants who go on to have an ASD diagnosis show atypical language processing in the network of left-lateralized regions involved in healthy language perception by 12 months of age (44-48) . Moreover, these early differences are robust enough to indicate subsequent diagnostic outcome.…”