title: Intersubject variability of and genetic effects on the brain's functional connectivity during infancy.
abstract: Infancy is a period featuring a high level of intersubject variability but the brain basis for such variability and the potential genetic/environmental contributions remain largely unexplored. The assessment of the brain's functional connectivity during infancy by the resting state functional magnetic resonance imaging (rsfMRI) technique (Biswal et al., 1995) provides a unique means to probe the brain basis of intersubject variability during infancy. In this study, an unusually large typically developing human infant sample including 58 singletons, 132 dizygotic twins, and 98 monozygotic twins with rsfMRI scans during the first 2 years of life was recruited to delineate the spatial and temporal developmental patterns of both the intersubject variability of and genetic effects on the brain's functional connectivity. Through systematic voxelwise functional connectivity analyses, our results revealed that the intersubject variability at birth features lower variability in primary functional areas but higher values in association areas. Although the relative pattern remains largely consistent, the magnitude of intersubject variability undergoes an interesting U-shaped growth during the first 2 years of life. Overall, the intersubject variability patterns during infancy show both adult-like and infant-specific characteristics (Mueller et al., 2013). On the other hand, age-dependent genetic effects were observed showing significant but bidirectional relationships with intersubject variability. The temporal and spatial patterns of the intersubject variability of and genetic contributions to the brain's functional connectivity documented in this study shed light on the largely uncharted functional development of the brain during infancy.
authors.affiliation: Departments of Radiology, Biomedical Research Imaging Center, wgao@email.unc.edu.
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.affiliation: Departments of Radiology, Biomedical Research Imaging Center.
authors.forename: Amanda
authors.initials: A
authors.lastname: Elton
authors.affiliation: Biomedical Research Imaging Center, Biostatistics.
authors.forename: Hongtu
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Departments of Radiology, Biomedical Research Imaging Center.
authors.forename: Sarael
authors.initials: S
authors.lastname: Alcauter
authors.affiliation: Radiology, and.
authors.forename: J Keith
authors.identifier: http://orcid.org/0000-0001-7588-3520
authors.initials: JK
authors.lastname: Smith
authors.affiliation: Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599.
authors.forename: John H
authors.initials: JH
authors.lastname: Gilmore
authors.affiliation: Departments of Radiology, Biomedical Research Imaging Center.
authors.forename: Weili
authors.initials: W
authors.lastname: Lin
mesh_terms: D000367:Age Factors; D001921:Brain / Q000098:blood supply* / Q000254:growth & development*; D001931:Brain Mapping; D002657:Child Development / Q000502:physiology; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000098:blood supply / Q000502:physiology*; D009434:Neural Pathways / Q000098:blood supply / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D012146:Rest / Q000502:physiology; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic
chemical_list: D010100:Oxygen
keywords: early brain development; functional connectivity; genetic effects; infancy; intersubject variability; resting state