Abstract
Features of brain asymmetry have been implicated in a broad range of cognitive processes; however, their origins are still poorly understood. Using a new left-right symmetric, spatiotemporal cortical surface atlas, we investigated cortical asymmetries in 442 healthy term-born neonates using structural and functional magnetic resonance images from the Developing Human Connectome Project. Cortical asymmetries observed in the term cohort were contextualised in two ways: by comparing them against cortical asymmetries observed in 103 preterm neonates scanned at term-equivalent age, and by comparing structural asymmetries against those observed in 1110 healthy young adults from the Human Connectome Project. Our results demonstrate that the neonatal cortex is markedly asymmetric in both structure and function, and while associations with preterm birth and biological sex were minimal, significant differences exist between birth and adulthood. Although these changes may represent experience-dependent developmental milestones, longitudinal studies across the lifespan are required to fully address these hypotheses.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
1) Further symmetrisation of the neonatal surface template by averaging the left and right sulcal depth templates for each postmenstrual week 2) Investigating associations between cortical asymmetries, postmenstrual age and biological sex 3) Comparison of structural cortical asymmetries between healthy-term neonates and healthy young adults from the Human Connectome Project, using template-to-template registration 4) Adjusting for total brain volume and hemispheric volume asymmetry, as recommended by WIlliams, C. M., et al. (2022). Comparing brain asymmetries independently of brain size, NeuroImage 5) Smoothing structural cortical measures on individual surfaces instead of a global template 6) Increasing the Z-statistic threshold used to define the functional ROI masks required by FSL PALM, to ensure the functional asymmetries observed were real rather than the result of a liberal functional ROI mask
