Developmental Trajectories of the Fronto-Temporal Lobes from Infancy to Early Adulthood in Healthy Individuals

Abstract

Brain development during early life in healthy individuals is rapid and dynamic, indicating that this period plays a very important role in neural and functional development. The frontal and temporal lobes are known to play a particularly important role in cognition. The study of healthy frontal and temporal lobe development in children is therefore of considerable importance. A better understanding of how these brain regions develop could also aid in the diagnosis and treatment of neurodevelopmental disorders. Some devel-opmental studies have used magnetic resonance imaging (MRI) to examine infant brains, but it remains the case that relatively little is known about cortical brain development in the first few years of life. In the present study we examined whole brain, temporal lobe and frontal lobe developmental trajectories from infancy to early adulthood in healthy individuals, considering gender and brain hemisphere differences. We performed a cross-sectional, longitudinal morphometric MRI study of 114 healthy individuals (54 females and 60 males) aged 1 month to 25 years old (mean age ± SD 8.8 ± 6.9). We measured whole brain, temporal and frontal lobe gray matter (GM)/white matter (WM) volumes, following previously used protocols. There were significant non-linear age-related volume changes in all regions. Peak ages of whole brain, temporal lobe and frontal lobe development occurred around pre-adolescence (9-12 years old). GM volumes for all regions increased significantly as a function of age. Peak age was nevertheless lobe specific, with a pattern of earlier peak ages for females in both temporal and frontal lobes. Growth change in whole brain GM volume was larger in males than in females. However, GM volume growth changes for the temporal and frontal lobes showed a somewhat different pattern. GM volume for both temporal and frontal lobes showed a greater increase in females until around 5-6 years old, at which point this tendency reversed (GM volume changes in males became greater), with male GM volume increasing for a longer time than that of females. WM volume growth changes were similar across regions, all increasing rapidly until early childhood but slowing down thereafter. All regions displayed significant rightward volumetric asymmetry regardless of sex. Furthermore, the right temporal and frontal lobes showed a greater volumetric increase than the left for the first several years, with this tendency reversing at around 6 years of age. In addition, the left frontal and temporal lobes increased in volume for a longer period of time. Taken together, these findings indicated that brain developmental trajectories differ depending on brain region, sex and brain hemisphere. Gender-related factors such as sex hormones and functional laterality may affect brain development.

Effects of prenatal alcohol exposure on the development of white matter volume and change in executive function

“…Hence, postnatal development of white matter occurs after the direct teratogenic effect of alcohol in utero. In contrast, gray matter development, begins in utero (Tanaka et al, 2012; Rubia, 2013), hence the initial brain neurons may be directly affected by alcohol for a longer period. Gray matter volume also has a narrower developmental trajectory, as volumes peak in early adolescence (Giedd et al, 1999; Lenroot et al, 2009) instead of adulthood.…”

“…In typically developing children, post-natal development of white matter is more protracted than gray matter, and continues during childhood and adolescence and into midlife (Riddle et al, 2010; Welker and Patton, 2012). Specifically, during childhood and adolescence, there are significant age-related increases in white matter volume, with peak volumes occurring between 12 and 14 years in the frontal and temporal lobes to around 20–24 years for the parietal lobes (Giedd et al, 1999; Ge et al, 2002; Gogtay et al, 2004; Tamnes et al, 2010; Raznahan et al, 2011; Tanaka et al, 2012). Increases in white matter volume are attributed to increases in myelination and potentially to changes in the size, density, and number of white matter fibers over time (Paus et al, 1999; Welker and Patton, 2012).…”

Normal Development of Human Brain White Matter from Infancy to Early Adulthood: A Diffusion Tensor Imaging Study

“…To assess different stages of development, we defined three age groups: infants (age <6 years; 21 participants), children (age 6-10 years; 11 participants) and adolescents/adults (age >10 years; 20 participants). Age ranges were based on growth rates at 6 years of age (turning point of growth rates in this study) and findings of age (around 10 years of age) at which peak brain volume occurs (reported by our earlier MRI work [18,19]). ANOVAs were also performed to test for effects of hemisphere, sex, TOI (CGH, ILF, SLF), and age group, as well as to test the effects of parts of the CC (gCC, sCC), sex and age group.…”

Imaging structural and functional brain development in early childhood

“…Postnatally, brain volume increases more rapidly in male infants than in female infants, leading to a widening separation in brain sizes 16, 126 . These differences are probably driven by differences in surface area expansion, as the maturational trajectories of global and regional cortical thickness are highly similar in males and females 4, 20, 27 .…”