Twin-singleton developmental study of brain white matter anatomy

Abstract

Twin studies provide valuable insights into the analysis of genetic and environmental factors influencing human brain development. However, these findings may not generalize to singletons due to differences in pre- and postnatal environments. One would expect the effect of these differences to be greater during the early years of life. To address this concern, we compare longitudinal diffusion data of white matter regions for 26 singletons and 76 twins (monozygotic and dizygotic) from birth to 2 years of age. We use nonlinear mixed effect modeling where the temporal changes in the diffusion parameters are described by the Gompertz function. The Gompertz function describes growth trajectory in terms of intuitive parameters: asymptote, delay, and speed. We analyzed fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) for 21 regions of interest (ROIs). These ROIs included areas in the association, projection, and commissural fiber tracts. We did not find any differences in the diffusion parameters between monozygotic and dizygotic twins. In addition, FA and RD showed no developmental differences between singletons and twins for the regions analyzed. However, the delay parameter of the Gompertz function of AD for the anterior limb of the internal capsule and anterior corona radiata was significantly different between singletons and twins. Further analysis indicated that the differences are small, and twins “catch up” by the first few months of life. These results suggest that the effects of differences of pre- and postnatal environments between twins and singletons are minimal on white matter development and disappear early in life.

MRI of the Neonatal Brain: A Review of Methodological Challenges and Neuroscientific Advances

“…This asynchrony was also observed within a functional network such as the language network: the ventral pathways (uncinate, fronto‐occipital, middle and inferior longitudinal fascicles) appeared more mature than the dorsal ones (arcuate and superior longitudinal fascicles), although this difference decreased during infancy 115 . From birth to 2 years of age, the trajectories of DTI parameters also showed differences between bundles in terms of asymptote, delay, and speed 116 . Over this period, the maturational correlation between bundles seems to decrease, 117 perhaps providing the neural substrates of the asynchronous functional and behavioral acquisitions of infants.…”

The utility of twins in developmental cognitive neuroscience research: How twins strengthen the ABCD research design

“…Twin pair pregnancies are considered high-risk because of the increased associated risks of fetal death, premature birth and low birth weight (Morrison, 2005). However, behavioral and psychiatric literatures have generally failed to find important twin-singleton differences in later life (e.g., Barnes and Boutwell, 2013; Christensen et al, 2006; Johnson et al, 2002; Kendler et al, 1995; Ordaz et al, 2010; Sadeghi et al, 2017; Tsou et al, 2008), suggesting that with appropriate exclusionary criteria for prematurity, extreme perinatal complications, and low birth-weight, twins are very much like singletons.…”

Babytwins Study Sweden (BATSS): A multi-method infant twin study of genetic and environmental factors influencing infant brain and behavioral development

“…Diffusion Tensor Imaging studies suggest significant heritability of early white matter, but substantial regional differentiation, which may reflect the different developmental or maturational timescales of different white matter tracts, for example, in terms of myelination, as well as time periods with more environmental susceptibility (Geng et al, 2012;S. J. Lee et al, 2017;Sadeghi, Gilmore, & Gerig, 2017). To our knowledge, only one study has investigated functional MRI in young twins (Gao et al, 2014).…”