Toddlers later diagnosed with autism exhibit multiple structural abnormalities in temporal corpus callosum fibers

摘要: Interhemispheric functional connectivity abnormalities are often reported in autism and it is thus not surprising that structural defects of the corpus callosum (CC) consistently found using both traditional MRI DTI techniques. Past studies however, have subdivided CC into 2 or 3 segments without regard for where fibers may project to within cortex, placing limitations on our ability understand nature, timing neurobehavioral impact early autism. Leveraging a unique cohort 97 toddlers (68 autism; 29 typical) we utilized novel technique identified seven tracts according their cortical projections. Results revealed younger (<2.5 years old), but older with exhibited abnormally low mean, radial, axial diffusivity values connecting occipital lobes temporal lobes. Fractional anisotropy cross sectional area tract were significantly larger young These findings indicate water diffusion more restricted unidirectional who develop Such results be explained by potential overabundance small caliber axons generated excessive prenatal neural proliferation as proposed previous genetic, animal model, postmortem Furthermore, measures correlated outcome severity at later ages. regarding timing, location add accumulating evidence, which suggests altered inter-hemispheric connectivity, particularly across lobes, hallmark disorder.