Development of the Intrinsic Language Network in Preschool Children from Ages 3 to 5 Years.

Yaqiong Xiao,Mark Lauckner,Daniel S Margulies,Jens Brauer,Fucang Jia,Hongchang Zhai,Angela D Friederici,Xi-Nian Zuo

doi:10.1371/journal.pone.0165802

Abstract

Resting state studies of spontaneous fluctuations in the functional magnetic resonance imaging (fMRI) blood oxygen level dependent signal have shown great potential in mapping the intrinsic functional connectivity of the human brain underlying cognitive functions. The aim of the present study was to explore the developmental changes in functional networks of the developing human brain exemplified with the language network in typically developing preschool children. To this end, resting-sate fMRI data were obtained from native Chinese children at ages of 3 and 5 years, 15 in each age group. Resting-state functional connectivity (RSFC) was analyzed for four regions of interest; these are the left and right anterior superior temporal gyrus (aSTG), left posterior superior temporal gyrus (pSTG), and left inferior frontal gyrus (IFG). The comparison of these RSFC maps between 3- and 5-year-olds revealed that RSFC decreases in the right aSTG and increases in the left hemisphere between aSTG seed and IFG, between pSTG seed and IFG, as well as between IFG seed and posterior superior temporal sulcus. In a subsequent analysis, functional asymmetry of the language network seeding in aSTG, pSTG and IFG was further investigated. The results showed an increase of left lateralization in both RSFC of pSTG and of IFG from ages 3 to 5 years. The IFG showed a leftward lateralized trend in 3-year-olds, while pSTG demonstrated rightward asymmetry in 5-year-olds. These findings suggest clear developmental trajectories of the language network between 3- and 5-year-olds revealed as a function of age, characterized by increasing long-range connections and dynamic hemispheric lateralization with age. Our study provides new insights into the developmental changes of a well-established functional network in young children and also offers a basis for future cross-culture and cross-age studies of the resting-state language network.

Highlights

Since the seminal study of Biswal et al [1] resting-state functional magnetic resonance imaging has proven its great potential in the study of the intrinsic neural basis that underlies human cognitive systems
Functional connectivity maps seeding in the left anterior superior temporal gyrus (aSTG), left posterior superior temporal gyrus (pSTG), right aSTG and left inferior frontal gyrus (IFG) revealed similar distributed patterns of connections in both age groups (Fig 2)
For the left pSTG Resting-state functional connectivity (RSFC), in 3-year-olds, correlations were mainly observed in bilateral temporal cortices, inferior parietal lobe (IPL), middle frontal gyrus (MFG), IFG, vMPFC as well as posterior cingulate cortex/precuneus (PCC), while in 5-year-olds correlations with bilateral temporal cortices, dMPFC, and left IFG (BA 44) were found

Summary

Introduction

Since the seminal study of Biswal et al [1] resting-state functional magnetic resonance imaging (rs-fMRI) has proven its great potential in the study of the intrinsic neural basis that underlies human cognitive systems. The development of the language network has been investigated in both task-based fMRI data (e.g., [22, 23]) and LFFs analysis of task-based fMRI data that suggests a dominance of interhemispheric connectivity at birth and childhood in contrast to a clear intrahemispheric fronto-temporal connectivity in adults [24, 25]. These findings indicate changes of the language network as a function of age, still little known about the developmental trajectory of the intrinsic language network in children, in general and in non-Indoeuropean languages in particular

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