Abstract
Processing speed is an important contributor to working memory performance and fluid intelligence in young children. Myelinated white matter plays a central role in brain messaging, and likely mediates processing speed, but little is known about the relationship between myelination and processing speed in young children. In the present study, processing speed was measured through inspection times, and myelin volume fraction (VFM) was quantified using a multicomponent magnetic resonance imaging (MRI) approach in 2- to 5-years of age. Both inspection times and VFM were found to increase with age. Greater VFM in the right and left occipital lobes, the body of the corpus callosum, and the right cerebellum was significantly associated with shorter inspection times, after controlling for age. A hierarchical regression showed that VFM in the left occipital lobe predicted inspection times over and beyond the effects of age and the VFM in the other brain regions. These findings are consistent with the hypothesis that myelin supports processing speed in early childhood.
Highlights
Infants’ cognitive capacities increase in complexity with age, ensuring increasing adaptiveness to the environment throughout childhood
After controlling for age, the correlations were significant with myelin in the right and left occipital lobes, right cerebellum, and the splenium of the corpus callosum, all ps < 0.05, with additional trends for the right temporal lobes, left and right internal capsules, and right superior longitudinal fasciculus, ps < 0.10
The present study explored the relationship between processing speed, as measured by inspection times, and white matter myelin between 2 and 5 years of age
Summary
Infants’ cognitive capacities increase in complexity with age, ensuring increasing adaptiveness to the environment throughout childhood. By fitting a 3-pool tissue model to appropriately acquired data, mcDESPOT provides a quantitative estimate of the relative volume fraction of the myelin water pool (termed the myelin volume fraction, VFM), which is a surrogate measure of myelin content This method has been previously used to investigate white matter myelin developing in infants and young children, showing region-specific VFM development trajectories in early childhood [32,33,34,35]. Unlike other common measures of processing speed in early childhood, inspection times do not rely critically on response execution time, which tremendously vary in young children, and minimally tap executive demands (e.g., goal maintenance, information manipulation in working memory, motor response selection), reflecting processing speed [9]. We expected faster inspection times with age to be related to greater VFM, especially in posterior regions given that inspection times minimally reflect executive and motor abilities
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
