biostudies-literatureCalixto CHHS | NIH | NIH Office of the DirectorNIBIB NIH HHSNICHD NIH HHSOffice of Faculty Development at Boston Children's HospitalHHS | NIH | National Institute of Biomedical Imaging and BioengineeringHHS | NIH | National Institute of Neurological Disorders and StrokeHHS | NIH | Eunice Kennedy Shriver National Institute of Child Health and Human DevelopmentRosamund Stone Zander Translational Neuroscience Center, Boston Children's HospitalOffice of Faculty Development at Boston Children’s HospitalHHS | NIH | NIH Office of the Director (OD)American Roentgen Ray SocietyRosamund Stone Zander Translational Neuroscience Center, Boston Children’s HospitalAmerican Roentgen Ray Society (ARRS)NLM NIH HHSNINDS NIH HHSHHS | NIH | National Institute of Biomedical Imaging and Bioengineering (NIBIB)HHS | NIH | U.S. National Library of MedicineNIH HHSe2410341121https://www.ebi.ac.uk/biostudies/studies/S-EPMC11725871biostudies-literatureUnknown122(1)This study presents the construction of a comprehensive spatiotemporal atlas of white matter tracts in the fetal brain for every gestational week between 23 and 36 wk using diffusion MRI (dMRI). Our research leverages data collected from fetal MRI scans, capturing the dynamic changes in the brain's architecture and microstructure during this critical period. The atlas includes 60 distinct white matter tracts, including commissural, projection, and association fibers. We employed advanced fetal dMRI processing techniques and tractography to map and characterize the developmental trajectories of these tracts. Our findings reveal that the development of these tracts is characterized by complex patterns of fractional anisotropy (FA) and mean diffusivity (MD), coinciding with the intensity of hProceedings of the National Academy of Sciences of the United States of AmericaA detailed spatiotemporal atlas of the white matter tracts for the fetal brain.PMC11725871R01EB018988 R01 EB032366SupportR01 NS106030S10 OD0250111R01 EB013248R01 EB018988R01 LM013608R01 HD110772R01 EB032366Career Development AwardSchoolarshipR01 NS128281S10 OD025111Calixto CJaimes CWarfield SKPierotich LGholipour ADorigatti Soldatelli MKarimi DfalseA detailed spatiotemporal atlas of the white matter tracts for the fetal brain.This study presents the construction of a comprehensive spatiotemporal atlas of white matter tracts in the fetal brain for every gestational week between 23 and 36 wk using diffusion MRI (dMRI). Our research leverages data collected from fetal MRI scans, capturing the dynamic changes in the brain's architecture and microstructure during this critical period. The atlas includes 60 distinct white matter tracts, including commissural, projection, and association fibers. We employed advanced fetal dMRI processing techniques and tractography to map and characterize the developmental trajectories of these tracts. Our findings reveal that the development of these tracts is characterized by complex patterns of fractional anisotropy (FA) and mean diffusivity (MD), coinciding with the intensity of h2025-01-01T00:00:00Z2025 Jan2026-05-29T17:27:29.898Z2026-04-08T05:37:03.057ZS-EPMC117258713979305810.1073/pnas.2410341121